Programs & Examples On #Rampart

Apache Rampart - Axis2 Security Module

Angular directive how to add an attribute to the element?

You can try this:

<div ng-app="app">
    <div ng-controller="AppCtrl">
        <a my-dir ng-repeat="user in users" ng-click="fxn()">{{}}</a>

var app = angular.module('app', []);

function AppCtrl($scope) {
        $scope.users = [{ name: 'John', id: 1 }, { name: 'anonymous' }];
        $scope.fxn = function () {
            alert('It works');

app.directive("myDir", function ($compile) {
    return {
        scope: {ngClick: '='}

failed to open stream: HTTP wrapper does not support writeable connections

it is because of using web address, You can not use http to write data. don't use : http:// or https:// in your location for upload files or save data or somting like that. instead of of using $_SERVER["HTTP_REFERER"] use $_SERVER["DOCUMENT_ROOT"]. for example :

wrong :




The entitlements specified...profile. (0xE8008016). Error iOS 4.2

If you have the certificate for Apple IOS Developer, there is no need to set value for key:"Code Signing Entitlements". Build Settings -> Code Signing Entitlements -> delete any value there.

What is the difference between List and ArrayList?

There's no difference between list implementations in both of your examples. There's however a difference in a way you can further use variable myList in your code.

When you define your list as:

List myList = new ArrayList();

you can only call methods and reference members that are defined in the List interface. If you define it as:

ArrayList myList = new ArrayList();

you'll be able to invoke ArrayList-specific methods and use ArrayList-specific members in addition to those whose definitions are inherited from List.

Nevertheless, when you call a method of a List interface in the first example, which was implemented in ArrayList, the method from ArrayList will be called (because the List interface doesn't implement any methods).

That's called polymorphism. You can read up on it.

JavaScript - cannot set property of undefined

d = {} is an empty object right now.

And d[a] is also an empty object.

It does not have any key values. So you should initialize the key values to this.

d[a] = {

How to load images dynamically (or lazily) when users scrolls them into view

The Swiss Army knife of image lazy loading is YUI's ImageLoader.

Because there is more to this problem than simply watching the scroll position.

How can I move a tag on a git branch to a different commit?

To sum up if your remote is called origin and you're working on master branch:

git tag -d <tagname>
git push origin :refs/tags/<tagname>
git tag <tagname> <commitId>
git push origin <tagname>
  • Line 1 removes the tag in local env.
  • Line 2 removes the tag in remote env.
  • Line 3 adds the tag to different commit
  • Line 4 pushes the change to the remote

You can also exchange line 4 to git push origin --tags to push all the changes with tags from your local changes.

Basing on @stuart-golodetz, @greg-hewgill, @eedeep, @ben-hocking answers, comments below their answers and NateS comments below my answer.

SQL Error: ORA-00942 table or view does not exist

Because this post is the top one found on stackoverflow when searching for "ORA-00942: table or view does not exist insert", I want to mention another possible cause of this error (at least in Oracle 12c): a table uses a sequence to set a default value and the user executing the insert query does not have select privilege on the sequence. This was my problem and it took me an unnecessarily long time to figure it out.

To reproduce the problem, execute the following SQL as user1:

create sequence seq_customer_id;

create table customer (
c_id number(10) default seq_customer_id.nextval primary key,
name varchar(100) not null,
surname varchar(100) not null

grant select, insert, update, delete on customer to user2;

Then, execute this insert statement as user2:

insert into user1.customer (name,surname) values ('michael','jackson');

The result will be "ORA-00942: table or view does not exist" even though user2 does have insert and select privileges on user1.customer table and is correctly prefixing the table with the schema owner name. To avoid the problem, you must grant select privilege on the sequence:

grant select on seq_customer_id to user2;

Disable Chrome strict MIME type checking

The server should respond with the correct MIME Type for JSONP application/javascript and your request should tell jQuery you are loading JSONP dataType: 'jsonp'

Please see this answer for further details ! You can also have a look a this one as it explains why loading .js file with text/plain won't work.

View's SELECT contains a subquery in the FROM clause

As per documentation:

MySQL Docs

  • The SELECT statement cannot contain a subquery in the FROM clause.

Your workaround would be to create a view for each of your subqueries.

Then access those views from within your view view_credit_status

How do I convert NSMutableArray to NSArray?

NSArray *array = [mutableArray copy];

Copy makes immutable copies. This is quite useful because Apple can make various optimizations. For example sending copy to a immutable array only retains the object and returns self.

If you don't use garbage collection or ARC remember that -copy retains the object.

angularjs to output plain text instead of html



wraps a raw DOM element or HTML string as a jQuery element (If jQuery is not available, angular.element delegates to Angular's built-in subset of jQuery, called "jQuery lite" or "jqLite.")

So you simply could do:

angular.module('myApp.filters', []).
  filter('htmlToPlaintext', function() {
    return function(text) {
      return angular.element(text).text();


<div>{{myText | htmlToPlaintext}}</div>

What do we mean by Byte array?

A byte is 8 bits (binary data).

A byte array is an array of bytes (tautology FTW!).

You could use a byte array to store a collection of binary data, for example, the contents of a file. The downside to this is that the entire file contents must be loaded into memory.

For large amounts of binary data, it would be better to use a streaming data type if your language supports it.

String isNullOrEmpty in Java?

No, which is why so many other libraries have their own copy :)

How to compare two dates in php

Try this

$data1 = strtotime(\date("d/m/Y"));
$data1 = date_create($data1);
$data2 = date_create("21/06/2017");

if($data1 < $data2){
    return "The most current date is date1";

return "The most current date is date2";

Run batch file as a Windows service

No need for extra software. Use the task scheduler -> create task -> hidden. The checkbox for hidden is in the bottom left corner. Set the task to trigger on login (or whatever condition you like) and choose the task in the actions tab. Running it hidden ensures that the task runs silently in the background like a service.

Note that you must also set the program to run "whether the user is logged in or not" or the program will still run in the foreground.

Python truncate a long string

With regex:

re.sub(r'^(.{75}).*$', '\g<1>...', data)

Long strings are truncated:

>>> data="11111111112222222222333333333344444444445555555555666666666677777777778888888888"
>>> re.sub(r'^(.{75}).*$', '\g<1>...', data)

Shorter strings never get truncated:

>>> data="11111111112222222222333333"
>>> re.sub(r'^(.{75}).*$', '\g<1>...', data)

This way, you can also "cut" the middle part of the string, which is nicer in some cases:

re.sub(r'^(.{5}).*(.{5})$', '\g<1>...\g<2>', data)

>>> data="11111111112222222222333333333344444444445555555555666666666677777777778888888888"
>>> re.sub(r'^(.{5}).*(.{5})$', '\g<1>...\g<2>', data)

Difference Between One-to-Many, Many-to-One and Many-to-Many?

First of all, read all the fine print. Note that NHibernate (thus, I assume, Hibernate as well) relational mapping has a funny correspondance with DB and object graph mapping. For example, one-to-one relationships are often implemented as a many-to-one relationship.

Second, before we can tell you how you should write your O/R map, we have to see your DB as well. In particular, can a single Skill be possesses by multiple people? If so, you have a many-to-many relationship; otherwise, it's many-to-one.

Third, I prefer not to implement many-to-many relationships directly, but instead model the "join table" in your domain model--i.e., treat it as an entity, like this:

class PersonSkill 
    Person person;
    Skill skill;    

Then do you see what you have? You have two one-to-many relationships. (In this case, Person may have a collection of PersonSkills, but would not have a collection of Skills.) However, some will prefer to use many-to-many relationship (between Person and Skill); this is controversial.

Fourth, if you do have bidirectional relationships (e.g., not only does Person have a collection of Skills, but also, Skill has a collection of Persons), NHibernate does not enforce bidirectionality in your BL for you; it only understands bidirectionality of the relationships for persistence purposes.

Fifth, many-to-one is much easier to use correctly in NHibernate (and I assume Hibernate) than one-to-many (collection mapping).

Good luck!

Search for a particular string in Oracle clob column

Use dbms_lob.instr and dbms_lob.substr, just like regular InStr and SubstStr functions.
Look at simple example:

SQL> create table t_clob(
  2    id number,
  3    cl clob
  4  );

Tabela zosta¦a utworzona.

SQL> insert into t_clob values ( 1, ' xxxx abcd xyz qwerty 354657 [] ' );

1 wiersz zosta¦ utworzony.

SQL> declare
  2    i number;
  3  begin
  4    for i in 1..400 loop
  5        update t_clob set cl = cl || ' xxxx abcd xyz qwerty 354657 [] ';
  6    end loop;
  7    update t_clob set cl = cl || ' CALCULATION=[N]NEW.PRODUCT_NO=[T9856] OLD.PRODUCT_NO=[T9852].... -- with other text ';
  8    for i in 1..400 loop
  9        update t_clob set cl = cl || ' xxxx abcd xyz qwerty 354657 [] ';
 10    end loop;
 11  end;
 12  /

Procedura PL/SQL zosta¦a zako?czona pomytlnie.

SQL> commit;

Zatwierdzanie zosta¦o uko?czone.
SQL> select length( cl ) from t_clob;


SQL> select dbms_lob.instr( cl, 'NEW.PRODUCT_NO=[' ) from t_clob;


SQL> select dbms_lob.substr( cl, 5,dbms_lob.instr( cl, 'NEW.PRODUCT_NO=[' ) + length( 'NEW.PRODUCT_NO=[') ) new_product
  2  from t_clob;


Singletons vs. Application Context in Android?

My 2 cents:

I did notice that some singleton / static fields were reseted when my activity was destroyed. I noticed this on some low end 2.3 devices.

My case was very simple : I just have a private filed "init_done" and a static method "init" that I called from activity.onCreate(). I notice that the method init was re-executing itself on some re-creation of the activity.

While I cannot prove my affirmation, It may be related to WHEN the singleton/class was created/used first. When the activity get destroyed/recycled, it seem that all class that only this activity refer are recycled too.

I moved my instance of singleton to a sub class of Application. I acces them from the application instance. and, since then, did not notice the problem again.

I hope this can help someone.

Where is SQLite database stored on disk?

SQLite is created in your python directory where you installed the python.

VBA code to show Message Box popup if the formula in the target cell exceeds a certain value

Essentially you want to add code to the Calculate event of the relevant Worksheet.

In the Project window of the VBA editor, double-click the sheet you want to add code to and from the drop-downs at the top of the editor window, choose 'Worksheet' and 'Calculate' on the left and right respectively.

Alternatively, copy the code below into the editor of the sheet you want to use:

Private Sub Worksheet_Calculate()

If Sheets("MySheet").Range("A1").Value > 0.5 Then
    MsgBox "Over 50%!", vbOKOnly
End If

End Sub

This way, every time the worksheet recalculates it will check to see if the value is > 0.5 or 50%.

request exceeds the configured maxQueryStringLength when using [Authorize]

In the root web.config for your project, under the system.web node:

    <httpRuntime maxUrlLength="10999" maxQueryStringLength="2097151" />

In addition, I had to add this under the system.webServer node or I got a security error for my long query strings:

        <requestLimits maxUrl="10999" maxQueryString="2097151" />

Using stored procedure output parameters in C#

In your C# code, you are using transaction for the command. Just commit the transaction and after that access your parameter value, you will get the value. Worked for me. :)

How do I get some variable from another class in Java?

The code that you have is correct. To get a variable from another class you need to create an instance of the class if the variable is not static, and just call the explicit method to get access to that variable. If you put get and set method like the above is the same of declaring that variable public.

Put the method setNum private and inside the getNum assign the value that you want, you will have "get" access to the variable in that case

Shortcut for echo "<pre>";print_r($myarray);echo "</pre>";

Maybe you can build a function / static class Method that does exactly that. I use Kohana which has a nice function called:


That will do what you want. That's reduces it to only one line. A simple function will look like

function debug($input) {
    echo "<pre>";
    echo "</pre>";

Laravel Controller Subfolder routing

If you're using Laravel 5.3 or above, there's no need to get into so much of complexity like other answers have said. Just use default artisan command to generate a new controller. For eg, if I want to create a User controller in User folder. I would type

php artisan make:controller User/User

In routes,

Route::get('/dashboard', 'User\User@dashboard');

doing just this would be fine and now on localhost/dashboard is where the page resides.

Hope this helps.

How can I check if a Perl array contains a particular value?

You can use smartmatch feature in Perl 5.10 as follows:

For literal value lookup doing below will do the trick.

if ( "value" ~~ @array ) 

For scalar lookup, doing below will work as above.

if ($val ~~ @array)

For inline array doing below, will work as above.

if ( $var ~~ ['bar', 'value', 'foo'] ) 

In Perl 5.18 smartmatch is flagged as experimental therefore you need to turn off the warnings by turning on experimental pragma by adding below to your script/module:

use experimental 'smartmatch';

Alternatively if you want to avoid the use of smartmatch - then as Aaron said use:

if ( grep( /^$value$/, @array ) ) {

Can you "compile" PHP code and upload a binary-ish file, which will just be run by the byte code interpreter?

There are several "compilers" of PHP code. Most of them do not support all of PHP features, since these simply must be interpreted during run time.

We are using Phalanger - - that is supporting even those dirty PHP dynamic features, and still is able to compile them as .NET assembly, that can be distributed as a standalone DLL.

How to copy a char array in C?

Well, techincally you can…

typedef struct { char xx[18]; } arr_wrap;

char array1[18] = "abcdefg";
char array2[18];

*((arr_wrap *) array2) = *((arr_wrap *) array1);

printf("%s\n", array2);     /* "abcdefg" */

but it will not look very beautiful.

…Unless you use the C preprocessor…

    { struct _tmparrwrap_ { char xx[ARRSIZE]; }; *((struct _tmparrwrap_ *) DESTARR) = *((struct _tmparrwrap_ *) SRCARR); }

You can then do:

char array1[18] = "abcdefg";
char array2[18];

CC_MEMCPY(array2, array1, sizeof(array1));

printf("%s\n", array2);     /* "abcdefg" */

And it will work with any data type, not just char:

int numbers1[3] = { 1, 2, 3 };
int numbers2[3];

CC_MEMCPY(numbers2, numbers1, sizeof(numbers1));

printf("%d - %d - %d\n", numbers2[0], numbers2[1], numbers2[2]);     /* "abcdefg" */

(Yes, the code above is granted to work always and it's portable)

SQL - Query to get server's IP address

The server might have multiple IP addresses that it is listening on. If your connection has the VIEW SERVER STATE server permission granted to it, you can run this query to get the address you have connected to SQL Server:

SELECT dec.local_net_address
FROM sys.dm_exec_connections AS dec
WHERE dec.session_id = @@SPID;

This solution does not require you to shell out to the OS via xp_cmdshell, which is a technique that should be disabled (or at least strictly secured) on a production server. It may require you to grant VIEW SERVER STATE to the appropriate login, but that is a far smaller security risk than running xp_cmdshell.

The technique mentioned by GilM for the server name is the preferred one:


Using python PIL to turn a RGB image into a pure black and white image

A PIL only solution for creating a bi-level (black and white) image with a custom threshold:

from PIL import Image
img ='mB96s.png')
thresh = 200
fn = lambda x : 255 if x > thresh else 0
r = img.convert('L').point(fn, mode='1')'foo.png')

With just

r = img.convert('1')'foo.png')

you get a dithered image.

From left to right the input image, the black and white conversion result and the dithered result:

Input Image Black and White Result Dithered Result

You can click on the images to view the unscaled versions.

Android Preventing Double Click On A Button

Disable the button with setEnabled(false) until it is safe for the user to click it again.

Nested classes' scope?

class Outer(object):
    outer_var = 1

    class Inner(object):
        def inner_var(self):
            return Outer.outer_var

This isn't quite the same as similar things work in other languages, and uses global lookup instead of scoping the access to outer_var. (If you change what object the name Outer is bound to, then this code will use that object the next time it is executed.)

If you instead want all Inner objects to have a reference to an Outer because outer_var is really an instance attribute:

class Outer(object):
    def __init__(self):
        self.outer_var = 1

    def get_inner(self):
        return self.Inner(self)
        # "self.Inner" is because Inner is a class attribute of this class
        # "Outer.Inner" would also work, or move Inner to global scope
        # and then just use "Inner"

    class Inner(object):
        def __init__(self, outer):
            self.outer = outer

        def inner_var(self):
            return self.outer.outer_var

Note that nesting classes is somewhat uncommon in Python, and doesn't automatically imply any sort of special relationship between the classes. You're better off not nesting. (You can still set a class attribute on Outer to Inner, if you want.)

Angular.js vs Knockout.js vs Backbone.js

It depends on the nature of your application. And, since you did not describe it in great detail, it is an impossible question to answer. I find Backbone to be the easiest, but I work in Angular all day. Performance is more up to the coder than the framework, in my opinion.

Are you doing heavy DOM manipulation? I would use jQuery and Backbone.

Very data driven app? Angular with its nice data binding.

Game programming? None - direct to canvas; maybe a game engine.

Fatal Error :1:1: Content is not allowed in prolog

Someone should mark Johannes Weiß's comment as the answer to this question. That is exactly why xml documents can't just be loaded in a DOM Document class.

CocoaPods Errors on Project Build

if you added new target after creating Podfile, just delete Podfile, Podfile.lock , Pods folder and workspace then init pods ->then put your pods pod install

How to read response headers in angularjs?

The response headers in case of cors remain hidden. You need to add in response headers to direct the Angular to expose headers to javascript.

// From server response headers :
header("Access-Control-Allow-Methods: GET, POST, OPTIONS");
header("Access-Control-Allow-Headers: Origin, X-Requested-With, 
Content-Type, Accept, Authorization, X-Custom-header");
header("Access-Control-Expose-Headers: X-Custom-header");
header("X-Custom-header: $some data");

var data = res.headers.get('X-Custom-header');

Source :

Root element is missing

  1. Check the trees.config file which located in config folder... sometimes (I don't know why) this file became to be empty like someone delete the content inside... keep backup up of this file in your local pc then when this error appear - replace the server file with your local file. This is what i do when this error happened.

  2. check the available space on the server. sometimes this is the problem.

Good luck.

"message failed to fetch from registry" while trying to install any module

The only thing that worked for me on Elementary OS Luna, a Ubuntu Fork. I am on x86 architecture. I tried all the answers here but finally decided to install it from source.

First, make sure its not installed using the package manager:

sudo apt-get purge nodejs npm -y

I went to the download page to lookup the latest source & download it, You can use curl, wget or your browser to get it:

tar -xvf node-v0.10.34.tar.gz 
cd node-v0.10.34
sudo make install

The make might take a while. When done, you should have node and npm installed and working in your /usr/local/bin directory which should be already on your path. You should verify where it lives:

which npm node

I also had to change the permissions to get it to work:

sudo chown -R $USER /usr/local

If it didn't work check your path:

echo $PATH

Note that installing it this way, it will not be managed by apt-get package manager. Cheers!

How to connect to Mysql Server inside VirtualBox Vagrant?

Well, since neither of the given replies helped me, I had to look more, and found solution in this article.

And the answer in a nutshell is the following:

Connecting to MySQL using MySQL Workbench

Connection Method: Standard TCP/IP over SSH
SSH Hostname: <Local VM IP Address (set in PuPHPet)>
SSH Username: vagrant (the default username)
SSH Password: vagrant (the default password)
MySQL Hostname:
MySQL Server Port: 3306
Username: root
Password: <MySQL Root Password (set in PuPHPet)>

Using given approach I was able to connect to mysql database in vagrant from host Ubuntu machine using MySQL Workbench and also using Valentina Studio.

Selecting and manipulating CSS pseudo-elements such as ::before and ::after using javascript (or jQuery)

Why adding classes or attributes when you can just append a style to head

$('head').append('<style>.span:after{ content:'changed content' }</style>')

Parse query string in JavaScript

The following function will parse the search string with a regular expression, cache the result and return the value of the requested variable:

window.getSearch = function(variable) {
  var parsedSearch;
  parsedSearch = window.parsedSearch || (function() {
    var match, re, ret;
    re = /\??(.*?)=([^\&]*)&?/gi;
    ret = {};
    while (match = re.exec( {
      ret[match[1]] = match[2];
    return window.parsedSearch = ret;
  return parsedSearch[variable];

You can either call it once without any parameters and work with the window.parsedSearch object, or call getSearch subsequently. I haven't fully tested this, the regular expression might still need some tweaking...

How to only find files in a given directory, and ignore subdirectories using bash

If you just want to limit the find to the first level you can do:

 find /dev -maxdepth 1 -name 'abc-*'

... or if you particularly want to exclude the .udev directory, you can do:

 find /dev -name '.udev' -prune -o -name 'abc-*' -print

pandas groupby sort within groups

You can do it in one line -

df.groupby(['job']).apply(lambda x: x.sort_values(['count'], ascending=False).head(3)
.drop('job', axis=1))

what apply() does is that it takes each group of groupby and assigns it to the x in lambda function.

Assigning the return value of new by reference is deprecated

In PHP5 this idiom is deprecated

$obj_md =& new MDB2();

You sure you've not missed an ampersand in your sample code? That would generate the warning you state, but it is not required and can be removed.

To see why this idiom was used in PHP4, see this manual page (note that PHP4 is long dead and this link is to an archived version of the relevant page)

How do I get the list of keys in a Dictionary?

List<string> keyList = new List<string>(this.yourDictionary.Keys);

Load JSON text into class object in c#

copy your Json and paste at textbox on and click on Generate button,

A cs class will be generated use that cs file as below:

var generatedcsResponce = JsonConvert.DeserializeObject(yourJson);

where RootObject is the name of the generated cs file;

How to read single Excel cell value

Please try this. Maybe this could help you. It works for me.

string sValue = (range.Cells[_row, _column] as Microsoft.Office.Interop.Excel.Range).Value2.ToString();
//_row,_column your column & row number 
//eg: string sValue = (sheet.Cells[i + 9, 12] as Microsoft.Office.Interop.Excel.Range).Value2.ToString();
//sValue has your value

How do I convert from BLOB to TEXT in MySQL?

That's unnecessary. Just use SELECT CONVERT(column USING utf8) FROM..... instead of just SELECT column FROM...

What's the difference between using CGFloat and float?

As others have said, CGFloat is a float on 32-bit systems and a double on 64-bit systems. However, the decision to do that was inherited from OS X, where it was made based on the performance characteristics of early PowerPC CPUs. In other words, you should not think that float is for 32-bit CPUs and double is for 64-bit CPUs. (I believe, Apple's ARM processors were able to process doubles long before they went 64-bit.) The main performance hit of using doubles is that they use twice the memory and therefore might be slower if you are doing a lot of floating point operations.

Find package name for Android apps to use Intent to launch Market app from web

The following code will list them out:

adb shell dumpsys package <packagename>

How do you save/store objects in SharedPreferences on Android?

You can save object in preferences without using any library, first of all your object class must implement Serializable:

public class callModel implements Serializable {

private long pointTime;
private boolean callisConnected;

public callModel(boolean callisConnected,  long pointTime) {
    this.callisConnected = callisConnected;
    this.pointTime = pointTime;
public boolean isCallisConnected() {
    return callisConnected;
public long getPointTime() {
    return pointTime;


Then you can easily use these two method to convert object to string and string to object:

 public static <T extends Serializable> T stringToObjectS(String string) {
    byte[] bytes = Base64.decode(string, 0);
    T object = null;
    try {
        ObjectInputStream objectInputStream = new ObjectInputStream(new ByteArrayInputStream(bytes));
        object = (T) objectInputStream.readObject();
    } catch (Exception e) {
    return object;

 public static String objectToString(Parcelable object) {
    String encoded = null;
    try {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
        encoded = new String(Base64.encodeToString(byteArrayOutputStream.toByteArray(), 0));
    } catch (IOException e) {
    return encoded;

To save:

SharedPreferences  mPrefs = getPreferences(MODE_PRIVATE);
Editor prefsEditor = mPrefs.edit();
prefsEditor.putString("MyObject", objectToString(callModelObject));

To read

String value= mPrefs.getString("MyObject", "");
MyObject obj = stringToObjectS(value);

Where does Java's String constant pool live, the heap or the stack?

As explained by this answer, the exact location of the string pool is not specified and can vary from one JVM implementation to another.

It is interesting to note that until Java 7, the pool was in the permgen space of the heap on hotspot JVM but it has been moved to the main part of the heap since Java 7:

Area: HotSpot
Synopsis: In JDK 7, interned strings are no longer allocated in the permanent generation of the Java heap, but are instead allocated in the main part of the Java heap (known as the young and old generations), along with the other objects created by the application. This change will result in more data residing in the main Java heap, and less data in the permanent generation, and thus may require heap sizes to be adjusted. Most applications will see only relatively small differences in heap usage due to this change, but larger applications that load many classes or make heavy use of the String.intern() method will see more significant differences. RFE: 6962931

And in Java 8 Hotspot, Permanent Generation has been completely removed.

Javascript document.getElementById("id").value returning null instead of empty string when the element is an empty text box

For your code

var mytextvalue = document.getElementById("mytext");

mytextvalue will contain null if you have a document.write() statement before this code. So remove the document.write statement and you should get a proper text object in the variable mytextvalue.

This is caused by document.write changing the document.

How to implement Rate It feature in Android App

This solution is very similar to those presented above. The only difference is that you are going to be able to delay the prompt of the rating dialog per launches and days. If the remind me later button is pressed, then I will delay the pop up for 3 days and 10 launches. The same is done for those that selected to rate it, however the delays is longer (not to bother the user so soon in case that he has actually rated the app. This can be changed to not be shown again, then you will have to alter the code to your like). Hope it helps somebody!

public class AppRater {
    private final static String APP_TITLE = "your_app_name";
    private static String PACKAGE_NAME = "your_package_name";
    private static int DAYS_UNTIL_PROMPT = 5;
    private static int LAUNCHES_UNTIL_PROMPT = 10;
    private static long EXTRA_DAYS;
    private static long EXTRA_LAUCHES;
    private static SharedPreferences prefs;
    private static SharedPreferences.Editor editor;
    private static Activity activity;

    public static void app_launched(Activity activity1) {
        activity = activity1;

        Configs.sendScreenView("Avaliando App", activity);

        PACKAGE_NAME = activity.getPackageName();

        prefs = activity.getSharedPreferences("apprater", Context.MODE_PRIVATE);
        if (prefs.getBoolean("dontshowagain", false)) 

        editor = prefs.edit();

        EXTRA_DAYS = prefs.getLong("extra_days", 0);
        EXTRA_LAUCHES = prefs.getLong("extra_launches", 0);

        // Increment launch counter
        long launch_count = prefs.getLong("launch_count", 0) + 1;
        editor.putLong("launch_count", launch_count);

        // Get date of first launch
        Long date_firstLaunch = prefs.getLong("date_firstlaunch", 0);
        if (date_firstLaunch == 0) {
            date_firstLaunch = System.currentTimeMillis();
            editor.putLong("date_firstlaunch", date_firstLaunch);

        // Wait at least n days before opening
        if (launch_count >= (LAUNCHES_UNTIL_PROMPT + EXTRA_LAUCHES))
            if (System.currentTimeMillis() >= date_firstLaunch + (DAYS_UNTIL_PROMPT * 24 * 60 * 60 * 1000) + EXTRA_DAYS)


    public static void showRateDialog() {
        final Dialog dialog = new Dialog(activity);
        dialog.setTitle("Deseja avaliar o aplicativo " + APP_TITLE + "?");

        LinearLayout ll = new LinearLayout(activity);
        ll.setPadding(5, 5, 5, 5);

        TextView tv = new TextView(activity);
        tv.setText("Ajude-nos a melhorar o aplicativo com sua avaliação no Google Play!");
        tv.setPadding(5, 5, 5, 5);

        Button b1 = new Button(activity);
        b1.setText("Avaliar aplicativo " + APP_TITLE + "!");
        b1.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                Configs.sendHitEvents(Configs.APP_RATER, Configs.CATEGORIA_ANALYTICS, "Clique", "Avaliar", activity);

                activity.startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=" + PACKAGE_NAME)));
        LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) b1.getLayoutParams();
        params.setMargins(5, 3, 5, 3);

        Button b2 = new Button(activity);
        b2.setText("Lembre-me mais tarde!");
        b2.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                Configs.sendHitEvents(Configs.APP_RATER, Configs.CATEGORIA_ANALYTICS, "Clique", "Avaliar Mais Tarde", activity);
        params = (LinearLayout.LayoutParams) b2.getLayoutParams();
        params.setMargins(5, 3, 5, 3);

        Button b3 = new Button(activity);
        b3.setText("Não, obrigado!");
        b3.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                Configs.sendHitEvents(Configs.APP_RATER, Configs.CATEGORIA_ANALYTICS, "Clique", "Não Avaliar", activity);

                if (editor != null) {
                    editor.putBoolean("dontshowagain", true);
        params = (LinearLayout.LayoutParams) b3.getLayoutParams();
        params.setMargins(5, 3, 5, 0);

        dialog.setContentView(ll);       ;        

    private static void delayLaunches(int numberOfLaunches) {
        long extra_launches = prefs.getLong("extra_launches", 0) + numberOfLaunches;
        editor.putLong("extra_launches", extra_launches);

    private static void delayDays(int numberOfDays) {
        Long extra_days = prefs.getLong("extra_days", 0) + (numberOfDays * 1000 * 60 * 60 * 24);
        editor.putLong("extra_days", extra_days);

The Buttons have a specific color and background. The background is as shown in this xml file:

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

    <solid android:color="#2E78B9" />

        android:topRightRadius="6dp" />


source: Android approach for "Rate my application"

Count number of occurrences of a pattern in a file (even on same line)

Try this:

grep "string to search for" FileNameToSearch | cut -d ":" -f 4 | sort -n | uniq -c


grep "SMTP connect from unknown" maillog | cut -d ":" -f 4 | sort -n | uniq -c
  6  SMTP connect from unknown []
 54  SMTP connect from unknown []
  3  SMTP connect from unknown []

Property [title] does not exist on this collection instance

With get() method you get a collection (all data that match the query), try to use first() instead, it return only one element, like this:

$about = Page::where('page', 'about-me')->first();

Detecting when the 'back' button is pressed on a navbar

This works for me in iOS 9.3.x with Swift:

override func didMoveToParentViewController(parent: UIViewController?) {

    if parent == self.navigationController?.parentViewController {
        print("Back tapped")

Unlike other solutions here, this doesn't seem to trigger unexpectedly.

Resetting a form in Angular 2 after submit

I don't know if I'm on the right path, but I got it working on ng 2.4.8 with the following form/submit tags:

<form #heroForm="ngForm" (ngSubmit)="add(newHero); heroForm.reset()">
<!-- place your input stuff here -->
<button type="submit" class="btn btn-default" [disabled]="!heroForm.valid">Add hero</button>

Seems to do the trick and sets the form's fields to "pristine" again.

How to get a list of images on docker registry v2

Using "/v2/_catalog" and "/tags/list" endpoints you can't really list all the images. If you pushed a few different images and tagged them "latest" you can't really list the old images! You can still pull them if you refer to them using digest "docker pull ubuntu@sha256:ac13c5d2...". So the answer is - there is no way to list images you can only list tags which is not the same

Using reCAPTCHA on localhost

Google has recently changed stopped allowing localhost being allowed by default. (as touched upon by @Artur Cesar De Melo)This is under their FAQ's:

I'm getting an error "Localhost is not in the list of supported domains". This was working before, what should I do?

localhost domains are no longer supported by default. If you wish to continue supporting them for development you can add them to the list of supported domains for your site key. Go to the admin console to update your list of supported domains. We advise to use a separate key for development and production and to not allow localhost on your production site key.

1: Create a separate key for your development environment

2: Add to the list of allowed domains

3: Save changes and allow up to 30 mins for changes to take affect

Youtube - downloading a playlist - youtube-dl

In a shell, & is a special character, advising the shell to start everything up to the & as a process in the background. To avoid this behavior, you can put the URL in quotes. See the youtube-dl FAQ for more information.

Also beware of -citk. With the exception of -i, these options make little sense. See the youtube-dl FAQ for more information. Even -f mp4 looks very strange.

So what you want is:

youtube-dl -i -f mp4 --yes-playlist ''

Alternatively, you can just use the playlist ID:

youtube-dl -i PLwJ2VKmefmxpUJEGB1ff6yUZ5Zd7Gegn2

How to make sure that string is valid JSON using JSON.NET

Just to add something to @Habib's answer, you can also check if given JSON is from a valid type:

public static bool IsValidJson<T>(this string strInput)
    if(string.IsNullOrWhiteSpace(strInput)) return false;

    strInput = strInput.Trim();
    if ((strInput.StartsWith("{") && strInput.EndsWith("}")) || //For object
        (strInput.StartsWith("[") && strInput.EndsWith("]"))) //For array
            var obj = JsonConvert.DeserializeObject<T>(strInput);
            return true;
        catch // not valid
            return false;
        return false;

How to read fetch(PDO::FETCH_ASSOC);

Loop through the array like any other Associative Array:

while($data = $datas->fetch( PDO::FETCH_ASSOC )){ 
     print $data['title'].'<br>'; 


$resultset = $datas->fetchALL(PDO::FETCH_ASSOC);

echo '<pre>'.$resultset.'</pre>';

React.js inline style best practices

Some time we require to style some element from a component but if we have to display that component only ones or the style is so less then instead of using the CSS class we go for the inline style in react js. reactjs inline style is as same as HTML inline style just the property names are a little bit different

Write your style in any tag using style={{prop:"value"}}

import React, { Component } from "react";
    import { Redirect } from "react-router";

    class InlineStyle extends Component {
      constructor(props) {
        this.state = {};

      render() {
        return (
                  color: "red",
                  fontSize: 40,
                  background: "green"
                }}// this is inline style in reactjs

    export default InlineStyle;

Saving a high resolution image in R

A simpler way is

ggplot(data=df, aes(x=xvar, y=yvar)) + 

ggsave(path = path, width = width, height = height, device='tiff', dpi=700)

Convert datatable to JSON in C#

public static string ConvertIntoJson(DataTable dt)
    var jsonString = new StringBuilder();
    if (dt.Rows.Count > 0)
        for (int i = 0; i < dt.Rows.Count; i++)
            for (int j = 0; j < dt.Columns.Count; j++)
                jsonString.Append("\"" + dt.Columns[j].ColumnName + "\":\"" 
                    + dt.Rows[i][j].ToString().Replace('"','\"') + (j < dt.Columns.Count - 1 ? "\"," : "\""));

            jsonString.Append(i < dt.Rows.Count - 1 ? "}," : "}");
        return jsonString.Append("]").ToString();
        return "[]";
public static string ConvertIntoJson(DataSet ds)
    var jsonString = new StringBuilder();
    for (int i = 0; i < ds.Tables.Count; i++)
        jsonString.Append("\"" + ds.Tables[i].TableName + "\":");
        if (i < ds.Tables.Count - 1)
    return jsonString.ToString();

W3WP.EXE using 100% CPU - where to start?

We had this on a recursive query that was dumping tons of data to the output - have you double checked everything does exit and no infinite loops exist?

Might try to narrow it down with a single page - we found ANTS to not be much help in that same case either - what we ended up doing was running the site hit a page watch the CPU - hit the next page watch CPU - very methodical and time consuming but if you cant find it with some code tracing you might be out of luck -

We were able to use IIS log files to track it to a set of pages that were suspect -

Hope that helps !

Make body have 100% of the browser height


<html style="width:100%; height:100%; margin: 0; padding: 0;">
<body style="overflow:hidden; width:100%; height:100%; margin:0; padding:0;">

Downloading an entire S3 bucket?

When in Windows, my preferred GUI tool for this is Cloudberry Explorer for S3., Has a fairly polished file explorer, ftp-like interface.

Apache: Restrict access to specific source IP inside virtual host

For Apache 2.4, you would use the Require IP directive. So to only allow machines from the network (range -

<VirtualHost *:80>
    <Location />
      Require ip

And if you just want the localhost machine to have access, then there's a special Require local directive.

The local provider allows access to the server if any of the following conditions is true:

  • the client address matches
  • the client address is ::1
  • both the client and the server address of the connection are the same

This allows a convenient way to match connections that originate from the local host:

<VirtualHost *:80>
    <Location />
      Require local

Entity Framework Queryable async

There is a massive difference in the example you have posted, the first version:

var urls = await context.Urls.ToListAsync();

This is bad, it basically does select * from table, returns all results into memory and then applies the where against that in memory collection rather than doing select * from table where... against the database.

The second method will not actually hit the database until a query is applied to the IQueryable (probably via a linq .Where().Select() style operation which will only return the db values which match the query.

If your examples were comparable, the async version will usually be slightly slower per request as there is more overhead in the state machine which the compiler generates to allow the async functionality.

However the major difference (and benefit) is that the async version allows more concurrent requests as it doesn't block the processing thread whilst it is waiting for IO to complete (db query, file access, web request etc).

How can I escape a single quote?

If for some reason you cannot escape the apostrophe character and you can't change it into a HTML entity (as it was in my case for a specific Vue.js property) you can use replace to change it into different apostrophe character from the UTF8 characters set, for instance:

' - U+02BC
’ - U+2019

ASP.NET MVC - Set custom IIdentity or IPrincipal

I can't speak directly for ASP.NET MVC, but for ASP.NET Web Forms, the trick is to create a FormsAuthenticationTicket and encrypt it into a cookie once the user has been authenticated. This way, you only have to call the database once (or AD or whatever you are using to perform your authentication), and each subsequent request will authenticate based on the ticket stored in the cookie.

A good article on this: (broken link)


Since the link above is broken, I would recommend LukeP's solution in his answer above: - I would also suggest that the accepted answer be changed to that one.

Edit 2: An alternative for the broken link:

The system cannot find the file specified. in Visual Studio

The system cannot find the file specified usually means the build failed (which it will for your code as you're missing a # infront of include, you have a stray >> at the end of your cout line and you need std:: infront of cout) but you have the 'run anyway' option checked which means it runs an executable that doesn't exist. Hit F7 to just do a build and make sure it says '0 errors' before you try running it.

Code which builds and runs:

#include <iostream>

int main()
   std::cout << "Hello World";
   return 0;

How can I disable editing cells in a WPF Datagrid?

If you want to disable editing the entire grid, you can set IsReadOnly to true on the grid. If you want to disable user to add new rows, you set the property CanUserAddRows="False"

<DataGrid IsReadOnly="True" CanUserAddRows="False" />

Further more you can set IsReadOnly on individual columns to disable editing.

Cache busting via params

Two questions: Will this effectively break the cache?

Yes. Even Stack Overflow use this method, although I remember that they (with their millions of visitors per day and zillions of different client and proxy versions and configurations) have had some freak edge cases where even this was not enough to break the cache. But the general assumption is that this will work, and is a suitable method to break caching on clients.

Will the param cause the browser to then never cache the response from that url since the param indicates that this is dynamic content?

No. The parameter will not change the caching policy; the caching headers sent by the server still apply, and if it doesn't send any, the browser's defaults.

How to "pull" from a local branch into another one?

Quite old post, but it might help somebody new into git.

I will go with

git rebase master
  • much cleaner log history and no merge commits (if done properly)
  • need to deal with conflicts, but it's not that difficult.

Android Closing Activity Programmatically

you can use this.finish() if you want to close current activity.


Which Radio button in the group is checked?

If you want to get the index of the selected radio button inside a control you can use this method:

public static int getCheckedRadioButton(Control c)
    int i;
        Control.ControlCollection cc = c.Controls;
        for (i = 0; i < cc.Count; i++)
            RadioButton rb = cc[i] as RadioButton;
            if (rb.Checked)
                return i;
        i = -1;
    return i;

Example use:

int index = getCheckedRadioButton(panel1);

The code isn't that well tested, but it seems the index order is from left to right and from top to bottom, as when reading a text. If no radio button is found, the method returns -1.

Update: It turned out my first attempt didn't work if there's no radio button inside the control. I added a try and catch block to fix that, and the method now seems to work.

How to delete duplicate rows in SQL Server?

(select MAX(ID) from TBL1  where DUPVAL=a.DUPVAL 
group by DUPVAL
having count(DUPVAL)>1))

Environment variables in Eclipse

You can also start eclipse within a shell.

You export the enronment, before calling eclipse.

Example :

export MY_VAR="ADCA"
export PATH="/home/lala/bin;$PATH"

Then you can have multiple instances on eclipse with their own custome environment including workspace.

AngularJS - Passing data between pages

If you only need to share data between views/scopes/controllers, the easiest way is to store it in $rootScope. However, if you need a shared function, it is better to define a service to do that.

enable cors in .htaccess

Thanks to Devin, I figured out the solution for my SLIM application with multi domain access.

In htaccess:

SetEnvIf Origin "http(s)?://(www\.)?(|allowed.domain.two)$" AccessControlAllowOrigin=$0$1
Header set Access-Control-Allow-Origin %{AccessControlAllowOrigin}e env=AccessControlAllowOrigin
Header set Access-Control-Allow-Credentials true

in index.php

// Access-Control headers are received during OPTIONS requests

        header("Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS");         

        header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");
// instead of mapping:
$app->options('/(:x+)', function() use ($app) {
    //...return correct headers...

How to create the most compact mapping n ? isprime(n) up to a limit N?

public static boolean isPrime(int number) {
 if(number < 2)
   return false;
 else if(number == 2 || number == 3)
        return true;
      else {
        for(int i=2;i<=number/2;i++)
           if(number%i == 0)
             return false;
           else if(i==number/2)
                return true;
    return false;

Saving and loading objects and using pickle

The following works for me:

class Fruits: pass

banana = Fruits()

banana.color = 'yellow'
banana.value = 30

import pickle

filehandler = open("Fruits.obj","wb")

file = open("Fruits.obj",'rb')
object_file = pickle.load(file)

print(object_file.color, object_file.value, sep=', ')
# yellow, 30

Combine two (or more) PDF's

I've done this with PDFBox. I suppose it works similarly to iTextSharp.

Figuring out whether a number is a Double in Java

Reflection is slower, but works for a situation when you want to know whether that is of type Dog or a Cat and not an instance of Animal. So you'd do something like:

if(null != items.elementAt(1) && items.elementAt(1).getClass().toString().equals("Cat"))
//do whatever with cat.. not any other instance of animal.. eg. hideClaws();

Not saying the answer above does not work, except the null checking part is necessary.

Another way to answer that is use generics and you are guaranteed to have Double as any element of items.

List<Double> items = new ArrayList<Double>();

How to generate .env file for laravel?

If you have trouble viewing the .env file or it is not showing up in the project just do this: ls -a.
This allows to see the hidden files in Linux. You can also open the folder with Visual Studio Code and you will see the files and be able to modify them.

How to file split at a line number


# set first K lines:

# line count (N): 
N=$(wc -l < $file_name)

# length of the bottom file:
L=$(( $N - $K ))

# create the top of file: 
head -n $K $file_name > top_$file_name

# create bottom of file: 
tail -n $L $file_name > bottom_$file_name

Also, on second thought, split will work in your case, since the first split is larger than the second. Split puts the balance of the input into the last split, so

split -l 300000 file_name

will output xaa with 300k lines and xab with 100k lines, for an input with 400k lines.

fe_sendauth: no password supplied

This occurs if the password for the database is not given.

default="postgres://postgres:[email protected]:5432/DBname"

ReactNative: how to center text?



at the view

Converting timestamp to time ago in PHP e.g 1 day ago, 2 days ago...

Here's my solution for a notification module I built some time ago. It returns output similar to Facebook's notifications dropdown (eg. 1 day ago, Just now, etc).

public function getTimeDifference($time) {
    //Let's set the current time
    $currentTime = date('Y-m-d H:i:s');
    $toTime = strtotime($currentTime);

    //And the time the notification was set
    $fromTime = strtotime($time);

    //Now calc the difference between the two
    $timeDiff = floor(abs($toTime - $fromTime) / 60);

    //Now we need find out whether or not the time difference needs to be in
    //minutes, hours, or days
    if ($timeDiff < 2) {
        $timeDiff = "Just now";
    } elseif ($timeDiff > 2 && $timeDiff < 60) {
        $timeDiff = floor(abs($timeDiff)) . " minutes ago";
    } elseif ($timeDiff > 60 && $timeDiff < 120) {
        $timeDiff = floor(abs($timeDiff / 60)) . " hour ago";
    } elseif ($timeDiff < 1440) {
        $timeDiff = floor(abs($timeDiff / 60)) . " hours ago";
    } elseif ($timeDiff > 1440 && $timeDiff < 2880) {
        $timeDiff = floor(abs($timeDiff / 1440)) . " day ago";
    } elseif ($timeDiff > 2880) {
        $timeDiff = floor(abs($timeDiff / 1440)) . " days ago";

    return $timeDiff;

Why does Date.parse give incorrect results?

During recent experience writing a JS interpreter I wrestled plenty with the inner workings of ECMA/JS dates. So, I figure I'll throw in my 2 cents here. Hopefully sharing this stuff will help others with any questions about the differences among browsers in how they handle dates.

The Input Side

All implementations store their date values internally as 64-bit numbers that represent the number of milliseconds (ms) since 1970-01-01 UTC (GMT is the same thing as UTC). This date is the ECMAScript epoch that is also used by other languages such as Java and POSIX systems such as UNIX. Dates occurring after the epoch are positive numbers and dates prior are negative.

The following code is interpreted as the same date in all current browsers, but with the local timezone offset:

Date.parse('1/1/1970'); // 1 January, 1970

In my timezone (EST, which is -05:00), the result is 18000000 because that's how many ms are in 5 hours (it's only 4 hours during daylight savings months). The value will be different in different time zones. This behaviour is specified in ECMA-262 so all browsers do it the same way.

While there is some variance in the input string formats that the major browsers will parse as dates, they essentially interpret them the same as far as time zones and daylight saving is concerned even though parsing is largely implementation dependent.

However, the ISO 8601 format is different. It's one of only two formats outlined in ECMAScript 2015 (ed 6) specifically that must be parsed the same way by all implementations (the other is the format specified for Date.prototype.toString).

But, even for ISO 8601 format strings, some implementations get it wrong. Here is a comparison output of Chrome and Firefox when this answer was originally written for 1/1/1970 (the epoch) on my machine using ISO 8601 format strings that should be parsed to exactly the same value in all implementations:

Date.parse('1970-01-01T00:00:00Z');       // Chrome: 0         FF: 0
Date.parse('1970-01-01T00:00:00-0500');   // Chrome: 18000000  FF: 18000000
Date.parse('1970-01-01T00:00:00');        // Chrome: 0         FF: 18000000
  • In the first case, the "Z" specifier indicates that the input is in UTC time so is not offset from the epoch and the result is 0
  • In the second case, the "-0500" specifier indicates that the input is in GMT-05:00 and both browsers interpret the input as being in the -05:00 timezone. That means that the UTC value is offset from the epoch, which means adding 18000000ms to the date's internal time value.
  • The third case, where there is no specifier, should be treated as local for the host system. FF correctly treats the input as local time while Chrome treats it as UTC, so producing different time values. For me this creates a 5 hour difference in the stored value, which is problematic. Other systems with different offsets will get different results.

This difference has been fixed as of 2020, but other quirks exist between browsers when parsing ISO 8601 format strings.

But it gets worse. A quirk of ECMA-262 is that the ISO 8601 date–only format (YYYY-MM-DD) is required to be parsed as UTC, whereas ISO 8601 requires it to be parsed as local. Here is the output from FF with the long and short ISO date formats with no time zone specifier.

Date.parse('1970-01-01T00:00:00');       // 18000000
Date.parse('1970-01-01');                // 0

So the first is parsed as local because it's ISO 8601 date and time with no timezone, and the second is parsed as UTC because it's ISO 8601 date only.

So, to answer the original question directly, "YYYY-MM-DD" is required by ECMA-262 to be interpreted as UTC, while the other is interpreted as local. That's why:

This doesn't produce equivalent results:

console.log(new Date(Date.parse("Jul 8, 2005")).toString()); // Local
console.log(new Date(Date.parse("2005-07-08")).toString());  // UTC

This does:

console.log(new Date(Date.parse("Jul 8, 2005")).toString());
console.log(new Date(Date.parse("2005-07-08T00:00:00")).toString());

The bottom line is this for parsing date strings. The ONLY ISO 8601 string that you can safely parse across browsers is the long form with an offset (either ±HH:mm or "Z"). If you do that you can safely go back and forth between local and UTC time.

This works across browsers (after IE9):

console.log(new Date(Date.parse("2005-07-08T00:00:00Z")).toString());

Most current browsers do treat the other input formats equally, including the frequently used '1/1/1970' (M/D/YYYY) and '1/1/1970 00:00:00 AM' (M/D/YYYY hh:mm:ss ap) formats. All of the following formats (except the last) are treated as local time input in all browsers. The output of this code is the same in all browsers in my timezone. The last one is treated as -05:00 regardless of the host timezone because the offset is set in the timestamp:

console.log(Date.parse("1/1/1970 12:00:00 AM"));
console.log(Date.parse("Thu Jan 01 1970"));
console.log(Date.parse("Thu Jan 01 1970 00:00:00"));
console.log(Date.parse("Thu Jan 01 1970 00:00:00 GMT-0500"));

However, since parsing of even the formats specified in ECMA-262 is not consistent, it is recommended to never rely on the built–in parser and to always manually parse strings, say using a library and provide the format to the parser.

E.g. in moment.js you might write:

let m = moment('1/1/1970', 'M/D/YYYY'); 

The Output Side

On the output side, all browsers translate time zones the same way but they handle the string formats differently. Here are the toString functions and what they output. Notice the toUTCString and toISOString functions output 5:00 AM on my machine. Also, the timezone name may be an abbreviation and may be different in different implementations.

Converts from UTC to Local time before printing

 - toString
 - toDateString
 - toTimeString
 - toLocaleString
 - toLocaleDateString
 - toLocaleTimeString

Prints the stored UTC time directly

 - toUTCString
 - toISOString 

In Chrome
toString            Thu Jan 01 1970 00:00:00 GMT-05:00 (Eastern Standard Time)
toDateString        Thu Jan 01 1970
toTimeString        00:00:00 GMT-05:00 (Eastern Standard Time)
toLocaleString      1/1/1970 12:00:00 AM
toLocaleDateString  1/1/1970
toLocaleTimeString  00:00:00 AM

toUTCString         Thu, 01 Jan 1970 05:00:00 GMT
toISOString         1970-01-01T05:00:00.000Z

In Firefox
toString            Thu Jan 01 1970 00:00:00 GMT-05:00 (Eastern Standard Time)
toDateString        Thu Jan 01 1970
toTimeString        00:00:00 GMT-0500 (Eastern Standard Time)
toLocaleString      Thursday, January 01, 1970 12:00:00 AM
toLocaleDateString  Thursday, January 01, 1970
toLocaleTimeString  12:00:00 AM

toUTCString         Thu, 01 Jan 1970 05:00:00 GMT
toISOString         1970-01-01T05:00:00.000Z

I normally don't use the ISO format for string input. The only time that using that format is beneficial to me is when dates need to be sorted as strings. The ISO format is sortable as-is while the others are not. If you have to have cross-browser compatibility, either specify the timezone or use a compatible string format.

The code new Date('12/4/2013').toString() goes through the following internal pseudo-transformation:

  "12/4/2013" -> toUCT -> [storage] -> toLocal -> print "12/4/2013"

I hope this answer was helpful.

Map isn't showing on Google Maps JavaScript API v3 when nested in a div tag

In my case I was getting the grey background and it turned out to be inclusion of a zoom value in the map options. Yup, makes no sense.

Get current url in Angular

You can make use of location service available in @angular/common and via this below code you can get the location or current URL

import { Component, OnInit } from '@angular/core';
import { Location } from '@angular/common';
import { Router } from '@angular/router';

  selector: 'app-top-nav',
  templateUrl: './top-nav.component.html',
  styleUrls: ['./top-nav.component.scss']
export class TopNavComponent implements OnInit {

  route: string;

  constructor(location: Location, router: Router) { => {
      if(location.path() != ''){
        this.route = location.path();
      } else {
        this.route = 'Home'

  ngOnInit() {


here is the reference link from where I have copied thing to get location for my project.

How to preserve request url with nginx proxy_pass

To perfectly forward without chopping the absoluteURI of the request and the Host in the header:

server {
    listen 35005;

    location / {
        rewrite            ^(.*)$   "://$http_host$uri$is_args$args";
        rewrite            ^(.*)$   "http$uri$is_args$args" break;
        proxy_set_header   Host     $host;


Found here:

textarea's rows, and cols attribute in CSS

I just wanted to post a demo using calc() for setting rows/height, since no one did.

body {_x000D_
  /* page default */_x000D_
  font-size: 15px;_x000D_
  line-height: 1.5;_x000D_
textarea {_x000D_
  /* demo related */_x000D_
  width: 300px;_x000D_
  margin-bottom: 1em;_x000D_
  display: block;_x000D_
  /* rows related */_x000D_
  font-size: inherit;_x000D_
  line-height: inherit;_x000D_
  padding: 3px;_x000D_
textarea.border-box {_x000D_
  box-sizing: border-box;_x000D_
textarea.rows-5 {_x000D_
  /* height: calc(font-size * line-height * rows); */_x000D_
  height: calc(1em * 1.5 * 5);_x000D_
textarea.border-box.rows-5 {_x000D_
  /* height: calc(font-size * line-height * rows + padding-top + padding-bottom + border-top-width + border-bottom-width); */_x000D_
  height: calc(1em * 1.5 * 5 + 3px + 3px + 1px + 1px);_x000D_
<p>height is 2 rows by default</p>_x000D_
<textarea>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</textarea>_x000D_
<p>height is 5 now</p>_x000D_
<textarea class="rows-5">Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</textarea>_x000D_
<p>border-box height is 5 now</p>_x000D_
<textarea class="border-box rows-5">Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</textarea>

If you use large values for the paddings (e.g. greater than 0.5em), you'll start to see the text that overflows the content(-box) area, and that might lead you to think that the height is not exactly x rows (that you set), but it is. To understand what's going on, you might want to check out The box model and box-sizing pages.

Creating files in C++

Here is my solution:

#include <fstream>

int main()
    std::ofstream ("Hello.txt");
    return 0;

File (Hello.txt) is created even without ofstream name, and this is the difference from Mr. Boiethios answer.

How do I include a Perl module that's in a different directory?

EDIT: Putting the right solution first, originally from this question. It's the only one that searches relative to the module directory:

use FindBin;                 # locate this script
use lib "$FindBin::Bin/..";  # use the parent directory
use yourlib;

There's many other ways that search for libraries relative to the current directory. You can invoke perl with the -I argument, passing the directory of the other module:

perl -I..

You can include a line near the top of your perl script:

use lib '..';

You can modify the environment variable PERL5LIB before you run the script:

export PERL5LIB=$PERL5LIB:..

The push(@INC) strategy can also work, but it has to be wrapped in BEGIN{} to make sure that the push is run before the module search:

BEGIN {push @INC, '..'}
use yourlib;

MongoDB and "joins"

If you use mongoose, you can just use(assuming you're using subdocuments and population):

Profile.findById profileId
  .select 'friends'
  .exec (err, profile) ->
    if err or not profile
      handleError err, profile, res
      Status.find { profile: { $in: profile.friends } }, (err, statuses) ->
        if err
          handleErr err, statuses, res
          res.json createJSON statuses

It retrieves Statuses which belong to one of Profile (profileId) friends. Friends is array of references to other Profiles. Profile schema with friends defined:

schema = new mongoose.Schema
  # ...

  friends: [
    type: mongoose.Schema.Types.ObjectId
    ref: 'Profile'
    unique: true
    index: true

How to edit default dark theme for Visual Studio Code?

You cannot "edit" a default theme, they are "locked in"

However, you can copy it into your own custom theme, with the exact modifications you'd like.

For more info, see these articles:

If all you want to change is the colors for C++ code, you should look at overwriting the c++ support colorizer. For info about that, go here:

EDIT: The dark theme is found here:

EDIT2: To clarify:


9.5 and newer:

PostgreSQL 9.5 and newer support INSERT ... ON CONFLICT (key) DO UPDATE (and ON CONFLICT (key) DO NOTHING), i.e. upsert.


Quick explanation.

For usage see the manual - specifically the conflict_action clause in the syntax diagram, and the explanatory text.

Unlike the solutions for 9.4 and older that are given below, this feature works with multiple conflicting rows and it doesn't require exclusive locking or a retry loop.

The commit adding the feature is here and the discussion around its development is here.

If you're on 9.5 and don't need to be backward-compatible you can stop reading now.

9.4 and older:

PostgreSQL doesn't have any built-in UPSERT (or MERGE) facility, and doing it efficiently in the face of concurrent use is very difficult.

This article discusses the problem in useful detail.

In general you must choose between two options:

  • Individual insert/update operations in a retry loop; or
  • Locking the table and doing batch merge

Individual row retry loop

Using individual row upserts in a retry loop is the reasonable option if you want many connections concurrently trying to perform inserts.

The PostgreSQL documentation contains a useful procedure that'll let you do this in a loop inside the database. It guards against lost updates and insert races, unlike most naive solutions. It will only work in READ COMMITTED mode and is only safe if it's the only thing you do in the transaction, though. The function won't work correctly if triggers or secondary unique keys cause unique violations.

This strategy is very inefficient. Whenever practical you should queue up work and do a bulk upsert as described below instead.

Many attempted solutions to this problem fail to consider rollbacks, so they result in incomplete updates. Two transactions race with each other; one of them successfully INSERTs; the other gets a duplicate key error and does an UPDATE instead. The UPDATE blocks waiting for the INSERT to rollback or commit. When it rolls back, the UPDATE condition re-check matches zero rows, so even though the UPDATE commits it hasn't actually done the upsert you expected. You have to check the result row counts and re-try where necessary.

Some attempted solutions also fail to consider SELECT races. If you try the obvious and simple:



UPDATE testtable
SET somedata = 'blah'
WHERE id = 2;

-- Remember, this is WRONG. Do NOT COPY IT.

INSERT INTO testtable (id, somedata)
SELECT 2, 'blah'


then when two run at once there are several failure modes. One is the already discussed issue with an update re-check. Another is where both UPDATE at the same time, matching zero rows and continuing. Then they both do the EXISTS test, which happens before the INSERT. Both get zero rows, so both do the INSERT. One fails with a duplicate key error.

This is why you need a re-try loop. You might think that you can prevent duplicate key errors or lost updates with clever SQL, but you can't. You need to check row counts or handle duplicate key errors (depending on the chosen approach) and re-try.

Please don't roll your own solution for this. Like with message queuing, it's probably wrong.

Bulk upsert with lock

Sometimes you want to do a bulk upsert, where you have a new data set that you want to merge into an older existing data set. This is vastly more efficient than individual row upserts and should be preferred whenever practical.

In this case, you typically follow the following process:


  • COPY or bulk-insert the new data into the temp table

  • LOCK the target table IN EXCLUSIVE MODE. This permits other transactions to SELECT, but not make any changes to the table.

  • Do an UPDATE ... FROM of existing records using the values in the temp table;

  • Do an INSERT of rows that don't already exist in the target table;

  • COMMIT, releasing the lock.

For example, for the example given in the question, using multi-valued INSERT to populate the temp table:


CREATE TEMPORARY TABLE newvals(id integer, somedata text);

INSERT INTO newvals(id, somedata) VALUES (2, 'Joe'), (3, 'Alan');


UPDATE testtable
SET somedata = newvals.somedata
FROM newvals

INSERT INTO testtable
SELECT, newvals.somedata
FROM newvals
LEFT OUTER JOIN testtable ON ( =


Related reading

What about MERGE?

SQL-standard MERGE actually has poorly defined concurrency semantics and is not suitable for upserting without locking a table first.

It's a really useful OLAP statement for data merging, but it's not actually a useful solution for concurrency-safe upsert. There's lots of advice to people using other DBMSes to use MERGE for upserts, but it's actually wrong.

Other DBs:

What is the difference between procedural programming and functional programming?

To expand on Konrad's comment:

and the order of evaluation is not well-defined

Some functional languages have what is called Lazy Evaluation. Which means a function is not executed until the value is needed. Until that time the function itself is what is passed around.

Procedural languages are step 1 step 2 step 3... if in step 2 you say add 2 + 2, it does it right then. In lazy evaluation you would say add 2 + 2, but if the result is never used, it never does the addition.

How to enter in a Docker container already running with a new TTY

docker exec -t -i container_name /bin/bash

Will take you to the containers console.

Disable all dialog boxes in Excel while running VB script?

Solution: Automation Macros

It sounds like you would benefit from using an automation utility. If you were using a windows PC I would recommend AutoHotkey. I haven't used automation utilities on a Mac, but this Ask Different post has several suggestions, though none appear to be free.

This is not a VBA solution. These macros run outside of Excel and can interact with programs using keyboard strokes, mouse movements and clicks.

Basically you record or write a simple automation macro that waits for the Excel "Save As" dialogue box to become active, hits enter/return to complete the save action and then waits for the "Save As" window to close. You can set it to run in a continuous loop until you manually end the macro.

Here's a simple version of a Windows AutoHotkey script that would accomplish what you are attempting to do on a Mac. It should give you an idea of the logic involved.

Example Automation Macro: AutoHotkey

; ' Infinite loop.  End the macro by closing the program from the Windows taskbar.
Loop {

    ; ' Wait for ANY "Save As" dialogue box in any program.
    ; ' BE CAREFUL!
    ; '  Ignore the "Confirm Save As" dialogue if attempt is made
    ; '  to overwrite an existing file.
    WinWait, Save As,,, Confirm Save As
    IfWinNotActive, Save As,,, Confirm Save As
        WinActivate, Save As,,, Confirm Save As
    WinWaitActive, Save As,,, Confirm Save As

    sleep, 250 ; ' 0.25 second delay
    Send, {ENTER} ; ' Save the Excel file.

    ; ' Wait for the "Save As" dialogue box to close.
    WinWaitClose, Save As,,, Confirm Save As

Undo a git stash

You can just run:

git stash pop

and it will unstash your changes.

If you want to preserve the state of files (staged vs. working), use

git stash apply --index

C#: Waiting for all threads to complete

I still think using Join is simpler. Record the expected completion time (as Now+timeout), then, in a loop, do

    throw new NotFinishedInTime();

EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0) on dispatch_semaphore_dispose

I had a different issue that brought me to this question, which will probably be more common than the overrelease issue in the accepted answer.

Root cause was our completion block being called twice due to bad if/else fallthrough in the network handler, leading to two calls of dispatch_group_leave for every one call to dispatch_group_enter.

Completion block called multiple times:

[self badMethodThatCallsMULTIPLECompletions:^(NSString *completion) {

    // this block is called multiple times
    // one `enter` but multiple `leave`


Debug via the dispatch_group's count

Upon the EXC_BAD_INSTRUCTION, you should still have access to your dispatch_group in the debugger. DispatchGroup: check how many "entered"

Print out the dispatch_group and you'll see:

<OS_dispatch_group: group[0x60800008bf40] = { xrefcnt = 0x2, refcnt = 0x1, port = 0x0, count = -1, waiters = 0 }>

When you see count = -1 it indicates that you've over-left the dispatch_group. Be sure to dispatch_enter and dispatch_leave the group in matched pairs.

Difference between maven scope compile and provided for JAR packaging

For a jar file, the difference is in the classpath listed in the MANIFEST.MF file included in the jar if addClassPath is set to true in the maven-jar-plugin configuration. 'compile' dependencies will appear in the manifest, 'provided' dependencies won't.

One of my pet peeves is that these two words should have the same tense. Either compiled and provided, or compile and provide.

Reactjs setState() with a dynamic key name?

With ES6+ you can just do [${variable}]

How to inject a Map using the @Value Spring Annotation?

Here is how we did it. Two sample classes as follow:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
public class KafkaContainerConfig {

    protected KafkaConsumerProperties kafkaConsumerProperties;

    public ConsumerFactory<String, String> consumerFactory() {
        return new DefaultKafkaConsumerFactory<>(kafkaConsumerProperties.getKafkaConsumerConfig());

public class KafkaConsumerProperties {
    protected Map<String, Object> kafkaConsumerConfig = new HashMap<>();

    public Map<String, Object> getKafkaConsumerConfig() {
        return (kafkaConsumerConfig);

To provide the kafkaConsumer config from a properties file, you can use: mapname[key]=value

kafkaConsumerConfig[bootstrap.servers]=localhost:9092, localhost:9093, localhost:9094

To provide the kafkaConsumer config from a yaml file, you can use "[key]": value In application.yml file:

  "[bootstrap.servers]": localhost:9092, localhost:9093, localhost:9094
  "[]": test-consumer-group-local
  "[value.deserializer]": org.apache.kafka.common.serialization.StringDeserializer
  "[key.deserializer]": org.apache.kafka.common.serialization.StringDeserializer

Unpivot with column name

You may also try standard sql un-pivoting method by using a sequence of logic with the following code.. The following code has 3 steps:

  1. create multiple copies for each row using cross join (also creating subject column in this case)
  2. create column "marks" and fill in relevant values using case expression ( ex: if subject is science then pick value from science column)
  3. remove any null combinations ( if exists, table expression can be fully avoided if there are strictly no null values in base table)

     select *
        select name, subject,
        case subject
        when 'Maths' then maths
        when 'Science' then science
        when 'English' then english
        end as Marks
    from studentmarks
    Cross Join (values('Maths'),('Science'),('English')) AS Subjct(Subject)
    )as D
    where marks is not null;

Convert InputStream to BufferedReader

A BufferedReader constructor takes a reader as argument, not an InputStream. You should first create a Reader from your stream, like so:

Reader reader = new InputStreamReader(is);
BufferedReader br = new BufferedReader(reader);

Preferrably, you also provide a Charset or character encoding name to the StreamReader constructor. Since a stream just provides bytes, converting these to text means the encoding must be known. If you don't specify it, the system default is assumed.

Resource files not found from JUnit test cases

Main classes should be under src/main/java
test classes should be under src/test/java

If all in the correct places and still main classes are not accessible then
Right click project => Maven => Update Project
Hope so this will resolve the issue

Can't use WAMP , port 80 is used by IIS 7.5

goto services and stop the "World Wide Web Publishing Service" after restart the wamp server. after that start the "World Wide Web Publishing Service"

How to put img inline with text

Please make use of the code below to display images inline:

<img style='vertical-align:middle;' src='somefolder/icon.gif'>
<div style='vertical-align:middle; display:inline;'>
Your text here

How to fix "no valid 'aps-environment' entitlement string found for application" in Xcode 4.3?

First of all, you don't need the entitlements file unless you are adding custom key/value pairs that do not exist in the provisioning profile. When your app is built, any entitlements from the provisioning profile will be copied to the app.

Given that you still see an error message about missing entitlements, I can only assume the code signing options are not correct in the build settings.

You need to make sure the correct profile is selected for the "Debug" configuration, and to be safe, that you have selected the correct profile for both the "Debug" and child-node labelled "Any iOS SDK":

enter image description here

Although this screenshot shows the "Automatic Developer" profile selected, choose the exact provisioning profile you want from the drop down, just for testing purposes. It could be that Xcode is automatically choosing a different profile than the one you want.

Also be sure to do a clean build, completely delete the app from your device, etc. This is just to make sure you don't have some old fluff hanging around.

Javascript loop through object array?

It appears you may just have missed the "messages" property in the data, so the loop is likely iterating the root Object rather than the Array:

for (var key in data.messages) {
    var obj = data.messages[key];
    // ...

Unless data was set to messages before the given snippet.

Though, you should consider changing that to a normal for loop for the Array:

for (var i = 0, l = data.messages.length; i < l; i++) {
    var obj = data.messages[i];
    // ...

How to set the Android progressbar's height?

You can use the LinearProgressIndicator provided by the Material Components Library and the app:trackThickness attribute:


With 12dp:

enter image description here

With 4dp:

enter image description here

Note: it requires at least the version 1.3.0-alpha04.

Adding open/closed icon to Twitter Bootstrap collapsibles (accordions)

Another no-javascript solution that uses the collapse functionality itself:

/* Prevent block display and transition animation */, {
  display: inline; }
.expand-icon.collapsing {
  display: none; }

/* HTML Toggler with glyphicons */
<a data-toggle="collapse" href=".my-collapse">
 <span class="my-collapse collapse-icon collapse in">
  <span class="glyphicon glyphicon-collapse-up"></span>
 <span class="my-collapse expand-icon collapse">
  <span class="glyphicon glyphicon-expand"></span>   

adb server version doesn't match this client

I simply closed the htc sync application completely and tried again. It worked as it was supposed to.

In a unix shell, how to get yesterday's date into a variable?

You can use GNU date command as shown below

Getting Date In the Past

To get yesterday and earlier day in the past use string day ago:

date --date='yesterday'

date --date='1 day ago'

date --date='10 day ago'

date --date='10 week ago'

date --date='10 month ago'

date --date='10 year ago'

Getting Date In the Future

To get tomorrow and day after tomorrow (tomorrow+N) use day word to get date in the future as follows:

date --date='tomorrow'

date --date='1 day'

date --date='10 day'

date --date='10 week'

date --date='10 month'

date --date='10 year'

Good NumericUpDown equivalent in WPF?

A control that is missing from the original set of WPF controls, but much used, is the NumericUpDown control. It is a neat way to get users to select a number from a fixed range, in a small area. A slider could be used, but for compact forms with little horizontal real-estate, the NumericUpDown is essential.

Solution A (via WindowsFormsHost)

You can use the Windows Forms NumericUpDown control in WPF by hosting it in a WindowsFormsHost. Pay attention that you have to include a reference to System.Windows.Forms.dll assembly.

<Window x:Class="WpfApplication61.MainWindow"
        Title="MainWindow" Height="350" Width="525">

Solution B (custom)

There are several commercial and codeplex versions around, but both involve installing 3rd party dlls and overheads to your project. Far simpler to build your own, and a aimple way to do that is with the ScrollBar.

A vertical ScrollBar with no Thumb (just the repeater buttons) is in fact just what we want. It inherits rom RangeBase, so it has all the properties we need, like Min, Max, and SmallChange (set to 1, to restrict it to Integer values)

So we change the ScrollBar ControlTemplate. First we remove the Thumb and Horizontal trigger actions. Then we group the remains into a grid and add a TextBlock for the number:

<Grid Margin="2">
        <ColumnDefinition />
    <TextBlock VerticalAlignment="Center" FontSize="20" MinWidth="25" Text="{Binding Value, RelativeSource={RelativeSource TemplatedParent}}"/>
    <Grid Grid.Column="1" x:Name="GridRoot" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Background="{TemplateBinding Background}">
            <RowDefinition MaxHeight="18"/>
            <RowDefinition Height="0.00001*"/>
            <RowDefinition MaxHeight="18"/>
        <RepeatButton x:Name="DecreaseRepeat" Command="ScrollBar.LineDownCommand" Focusable="False">
                <Path x:Name="DecreaseArrow" Stroke="{TemplateBinding Foreground}" StrokeThickness="1" Data="M 0 4 L 8 4 L 4 0 Z"/>
        <RepeatButton Grid.Row="2" x:Name="IncreaseRepeat" Command="ScrollBar.LineUpCommand" Focusable="False">
                <Path x:Name="IncreaseArrow" Stroke="{TemplateBinding Foreground}" StrokeThickness="1" Data="M 0 0 L 4 4 L 8 0 Z"/>


Access elements of parent window from iframe

Have the below js inside the iframe and use ajax to submit the form.



       //Use ajax to submit the form
          url: this.action,
          data: $(this).serialize(),
          success: function(){



Vim and Ctags tips and tricks

I use ALT-left and ALT-right to pop/push from/to the tag stack.

" Alt-right/left to navigate forward/backward in the tags stack
map <M-Left> <C-T>
map <M-Right> <C-]>

If you use hjkl for movement you can map <M-h> and <M-l> instead.

C: printf a float value

You need to use %2.6f instead of %f in your printf statement

jquery change class name

change class using jquery

try this

$('#selector_id').attr('class','new class');

you can also set any attribute using this query

$('#selector_id').attr('Attribute Name','Attribute Value');

What are the best PHP input sanitizing functions?

You use mysql_real_escape_string() in code similar to the following one.

$query = sprintf("SELECT * FROM users WHERE user='%s' AND password='%s'",

As the documentation says, its purpose is escaping special characters in the string passed as argument, taking into account the current character set of the connection so that it is safe to place it in a mysql_query(). The documentation also adds:

If binary data is to be inserted, this function must be used.

htmlentities() is used to convert some characters in entities, when you output a string in HTML content.

Executing Batch File in C#

Here is sample c# code that are sending 2 parameters to a bat/cmd file for answer this question.

Comment: how can I pass parameters and read a result of command execution?

/by @Janatbek Sharsheyev

Option 1 : Without hiding the console window, passing arguments and without getting the outputs

using System;
using System.Diagnostics;

namespace ConsoleApplication
    class Program
        static void Main(string[] args)
         System.Diagnostics.Process.Start(@"c:\batchfilename.bat", "\"1st\" \"2nd\"");

Option 2 : Hiding the console window, passing arguments and taking outputs

using System;
using System.Diagnostics;

namespace ConsoleApplication
    class Program
        static void Main(string[] args)
         var process = new Process();
         var startinfo = new ProcessStartInfo(@"c:\batchfilename.bat", "\"1st_arg\" \"2nd_arg\" \"3rd_arg\"");
         startinfo.RedirectStandardOutput = true;
         startinfo.UseShellExecute = false;
         process.StartInfo = startinfo;
         process.OutputDataReceived += (sender, argsx) => Console.WriteLine(argsx.Data); // do whatever processing you need to do in this handler

How can I get customer details from an order in WooCommerce?

Having tried $customer = new WC_Customer(); and global $woocommerce; $customer = $woocommerce->customer; I was still getting empty address data even when I logged in as a non-admin user.

My solution was as follows:

function mwe_get_formatted_shipping_name_and_address($user_id) {

    $address = '';
    $address .= get_user_meta( $user_id, 'shipping_first_name', true );
    $address .= ' ';
    $address .= get_user_meta( $user_id, 'shipping_last_name', true );
    $address .= "\n";
    $address .= get_user_meta( $user_id, 'shipping_company', true );
    $address .= "\n";
    $address .= get_user_meta( $user_id, 'shipping_address_1', true );
    $address .= "\n";
    $address .= get_user_meta( $user_id, 'shipping_address_2', true );
    $address .= "\n";
    $address .= get_user_meta( $user_id, 'shipping_city', true );
    $address .= "\n";
    $address .= get_user_meta( $user_id, 'shipping_state', true );
    $address .= "\n";
    $address .= get_user_meta( $user_id, 'shipping_postcode', true );
    $address .= "\n";
    $address .= get_user_meta( $user_id, 'shipping_country', true );

    return $address;

...and this code works regardless of whether you are logged in as admin or not.

Sites not accepting wget user agent header

I created a ~/.wgetrc file with the following content (obtained from but with a newer user agent, because otherwise it didn’t work always):

header = Accept-Language: en-us,en;q=0.5
header = Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
header = Connection: keep-alive
user_agent = Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:40.0) Gecko/20100101 Firefox/40.0
referer = /
robots = off

Now I’m able to download from most (all?) file-sharing (streaming video) sites.

Difference between text and varchar (character varying)

character varying(n), varchar(n) - (Both the same). value will be truncated to n characters without raising an error.

character(n), char(n) - (Both the same). fixed-length and will pad with blanks till the end of the length.

text - Unlimited length.


Table test:
   a character(7)
   b varchar(7)

insert "ok    " to a
insert "ok    " to b

We get the results:

a        | (a)char_length | b     | (b)char_length
"ok     "| 7              | "ok"  | 2

Initializing a member array in constructor initializer


template<class T, size_t N>
struct simple_array { // like std::array in C++0x
   T arr[N];

class C : private simple_array<int, 3> 
      static simple_array<int, 3> myarr() {
           simple_array<int, 3> arr = {1,2,3};
           return arr;
      C() : simple_array<int, 3>(myarr()) {}

Ascending and Descending Number Order in java

I have done it in this manner (I'm new in java(also in programming))

import java.util.Scanner;

public class SortingNumbers {

public static void main(String[] args) {
    Scanner scan1=new Scanner(;
    System.out.print("How many numbers you want to sort: ");
    int a=scan1.nextInt();

    int i,j,k=0; // i and j is used in various loops.
    int num[]=new int[a];
    int great[]= new int[a];    //This array elements will be used to store "the number of being greater."  

    Scanner scan2=new Scanner(;
    System.out.println("Enter the numbers: ");

        num[i] = scan2.nextInt();

    for (i=0;i<a;i++) {
        for(j=0;j<a;j++) {
            if(num[i]>num[j])   //first time when executes this line, i=0 and j=0 and then i=0;j=1 and so on. each time it finishes second for loop the value of num[i] changes.
    great[i]=k++;  //At the end of each for loop (second one) k++ contains the total of how many times a number is greater than the others.
    k=0;}  // And then, again k is forced to 0, so that it can collect (the total of how many times a number is greater) for another number.

    System.out.print("Ascending Order: ");
            if(great[j]==i) System.out.print(num[j]+","); //there is a fixed value for each great[j] that is, from 0 upto number of elements(input numbers).
    System.out.print("Discending Order: ");
            if(great[j]==a-i) System.out.print(+num[j]+",");


Span inside anchor or anchor inside span or doesn't matter?

Semantically I think makes more sense as is a container for a single element and if you need to nest them then that suggests more than element will be inside of the outer one.

Format a JavaScript string using placeholders and an object of substitutions?

You can use JQuery(jquery.validate.js) to make it work easily.

$.validator.format("My name is {0}, I'm {1} years old",["Bob","23"]);

Or if you want to use just that feature you can define that function and just use it like

function format(source, params) {
    $.each(params,function (i, n) {
        source = source.replace(new RegExp("\\{" + i + "\\}", "g"), n);
    return source;
alert(format("{0} is a {1}", ["Michael", "Guy"]));

credit to jquery.validate.js team

Capturing multiple line output into a Bash variable

In addition to the answer given by @l0b0 I just had the situation where I needed to both keep any trailing newlines output by the script and check the script's return code. And the problem with l0b0's answer is that the 'echo x' was resetting $? back to zero... so I managed to come up with this very cunning solution:

RESULTX="$(./myscript; echo x$?)"

How do I put a border around an Android textview?

Try this:

    <solid android:color="@color/txt_white"/>
    <stroke android:width="1dip" android:color="@color/border_black"/>

Gaussian fit for Python

After losing hours trying to find my error, the problem is your formula:

sigma = sum(y*(x-mean)**2)/n

This previous formula is wrong, the correct formula is the square root of this!;


Hope this helps

Why does JavaScript only work after opening developer tools in IE once?

We ran into this problem on IE 11 on Windows 7 and Windows 10. We discovered what exactly the problem was by turning on debugging capabilities for IE (IE > Internet Options > Advanced tab > Browsing > Uncheck Disable script debugging (Internet Explorer)). This feature is typically checked on within our environment by the domain admins.

The problem was because we were using the console.debug(...) method within our JavaScript code. The assumption made by the developer (me) was I did not want anything written if the client Developer Tools console was not explicitly open. While Chrome and Firefox seemed to agree with this strategy, IE 11 did not like it one bit. By changing all the console.debug(...) statements to console.log(...) statements, we were able to continue to log additional information in the client console and view it when it was open, but otherwise keep it hidden from the typical user.

How to print the value of a Tensor object in TensorFlow?

I think you need to get some fundamentals right. With the examples above you have created tensors (multi dimensional array). But for tensor flow to really work you have to initiate a "session" and run your "operation" in the session. Notice the word "session" and "operation". You need to know 4 things to work with tensorflow:

  1. tensors
  2. Operations
  3. Sessions
  4. Graphs

Now from what you wrote out you have given the tensor, and the operation but you have no session running nor a graph. Tensor (edges of the graph) flow through graphs and are manipulated by operations (nodes of the graph). There is default graph but you can initiate yours in a session.

When you say print , you only access the shape of the variable or constant you defined.

So you can see what you are missing :

 with tf.Session() as sess:     
           print (product.eval())

Hope it helps!

How to auto import the necessary classes in Android Studio with shortcut?

You can also use Eclipse's keyboard shortcuts: just go on preferences > keymap and choose Eclipse from the drop-down menu. And all your Eclipse shortcuts will be used in here.

List(of String) or Array or ArrayList

Neither collection will let you add items that way.

You can make an extension to make for examle List(Of String) have an Add method that can do that:

Imports System.Runtime.CompilerServices
Module StringExtensions

  Public Sub Add(ByVal list As List(Of String), ParamArray values As String())
    For Each s As String In values
  End Sub

End Module

Now you can add multiple value in one call:

Dim lstOfStrings as New List(Of String)
lstOfStrings.Add(String1, String2, String3, String4)

Batch: Remove file extension

I'm also a stranger to windows cmd, but try this:

echo %%~nf

How to automatically generate getters and setters in Android Studio

Right click on Editor then Select Source -> Generate Getters and Setters or press Alt + Shift + S enter image description here

Eclipse Java Missing required source folder: 'src'

In my case eclipse reported this in the Problems view on the parent project which does not have any code. I just delete the error whenever it is reported on this parent project where src folder is really not needed.

How can I drop a table if there is a foreign key constraint in SQL Server?

Type this .... SET foreign_key_checks = 0;
delete your table then type SET foreign_key_checks = 1;

MySQL – Temporarily disable Foreign Key Checks or Constraints

How to vertically align a html radio button to it's label?

there are several way, one i would prefer is using a table in html. you can add two coloum three rows table and place the radio buttons and lable.

<table border="0">

  <td><input type="radio" name="sex" value="1"></td>

  <td><input type="radio" name="sex" value="2"></td>


SSL "Peer Not Authenticated" error with HttpClient 4.1

This is thrown when

... the peer was not able to identify itself (for example; no certificate, the particular cipher suite being used does not support authentication, or no peer authentication was established during SSL handshaking) this exception is thrown.

Probably the cause of this exception (where is the stacktrace) will show you why this exception is thrown. Most likely the default keystore shipped with Java does not contain (and trust) the root certificate of the TTP that is being used.

The answer is to retrieve the root certificate (e.g. from your browsers SSL connection), import it into the cacerts file and trust it using keytool which is shipped by the Java JDK. Otherwise you will have to assign another trust store programmatically.

Set default option in mat-select

On your typescript file, just assign this domain on modeSelect on Your ngOnInit() method like below:

 ngOnInit() {
        this.modeSelect = "domain";

And on your html, use your select list.

        <mat-select  [(value)]="modeSelect" placeholder="Mode">
          <mat-option value="domain">Domain</mat-option>
          <mat-option value="exact">Exact</mat-option>

How to gettext() of an element in Selenium Webdriver

You need to store it in a String variable first before displaying it like so:

String Txt = TxtBoxContent.getText();

How to set radio button checked as default in radiogroup?

It's a bug of RadioGroup

RadioButton radioBtn2 = new RadioButton(context);

radioBtn2 without viewId, and generateViewId is in onChildViewAdded()

public void onChildViewAdded(View parent, View child) {
    if (parent == RadioGroup.this && child instanceof RadioButton) {
        int id = child.getId();
        // generates an id if it's missing
        if (id == View.NO_ID) {
            id = View.generateViewId();
        ((RadioButton) child).setOnCheckedChangeWidgetListener(

    if (mOnHierarchyChangeListener != null) {
        mOnHierarchyChangeListener.onChildViewAdded(parent, child);

so, first radioGroup.addView(radioBtn2), then radioBtn2.setChecked(true);

Like this:

RadioGroup radioGroup = new RadioGroup(context);
RadioButton radioBtn1 = new RadioButton(context);
RadioButton radioBtn2 = new RadioButton(context);
RadioButton radioBtn3 = new RadioButton(context);




When to use @QueryParam vs @PathParam

The reason is actually very simple. When using a query parameter you can take in characters such as "/" and your client does not need to html encode them. There are other reasons but that is a simple example. As for when to use a path variable. I would say whenever you are dealing with ids or if the path variable is a direction for a query.

When should I use h:outputLink instead of h:commandLink?

I also see that the page loading (performance) takes a long time on using h:commandLink than h:link. h:link is faster compared to h:commandLink

Bower: ENOGIT Git is not installed or not in the PATH

Just use the Git Bash instead of cmd.

What is the most effective way for float and double comparison?

Realizing this is an old thread but this article is one of the most straight forward ones I have found on comparing floating point numbers and if you want to explore more it has more detailed references as well and it the main site covers a complete range of issues dealing with floating point numbers The Floating-Point Guide :Comparison.

We can find a somewhat more practical article in Floating-point tolerances revisited and notes there is absolute tolerance test, which boils down to this in C++:

bool absoluteToleranceCompare(double x, double y)
    return std::fabs(x - y) <= std::numeric_limits<double>::epsilon() ;

and relative tolerance test:

bool relativeToleranceCompare(double x, double y)
    double maxXY = std::max( std::fabs(x) , std::fabs(y) ) ;
    return std::fabs(x - y) <= std::numeric_limits<double>::epsilon()*maxXY ;

The article notes that the absolute test fails when x and y are large and fails in the relative case when they are small. Assuming he absolute and relative tolerance is the same a combined test would look like this:

bool combinedToleranceCompare(double x, double y)
    double maxXYOne = std::max( { 1.0, std::fabs(x) , std::fabs(y) } ) ;

    return std::fabs(x - y) <= std::numeric_limits<double>::epsilon()*maxXYOne ;

What is "android.R.layout.simple_list_item_1"?

Per Arvand:
Eclipse: Simply type android.R.layout.simple_list_item_1 somewhere in code, hold Ctrl, hover over simple_list_item_1, and from the dropdown that appears select Open declaration in layout/simple_list_item_1.xml. It'll direct you to the contents of the XML.

From there, if you then hover over the resulting simple_list_item_1.xml tab in the Editor, you'll see the file is located at C:\Data\applications\Android\android-sdk\platforms\android-19\data\res\layout\simple_list_item_1.xml (or equivalent location for your installation).

MessageBox with YesNoCancel - No & Cancel triggers same event

I see all the answers are correct. I just want to write a little different piece of code. In my opinion, you may do it without using an extra variable to save the result of the dialogBox. Take a look:

VB Code

Select Case MsgBox("Your Message", MsgBoxStyle.YesNoCancel, "caption")
                    Case MsgBoxResult.Yes
                        MessageBox.Show("Yes button")
                    Case MsgBoxResult.Cancel
                        MessageBox.Show("Cancel button")
                    Case MsgBoxResult.No
                        MessageBox.Show("NO button")
 End Select

C# Code

switch (MessageBox.Show("Message", "caption", MessageBoxButtons.YesNoCancel))
            case DialogResult.Yes: MessageBox.Show("Yes"); break;
            case DialogResult.No: MessageBox.Show("No"); break;
            case DialogResult.Cancel: MessageBox.Show("Cancel");  break;

Finding index of character in Swift String

Here is a clean String extention that answers the question:

Swift 3:

extension String {
    var length:Int {
        return self.characters.count

    func indexOf(target: String) -> Int? {

        let range = (self as NSString).range(of: target)

        guard range.toRange() != nil else {
            return nil

        return range.location

    func lastIndexOf(target: String) -> Int? {

        let range = (self as NSString).range(of: target, options: NSString.CompareOptions.backwards)

        guard range.toRange() != nil else {
            return nil

        return self.length - range.location - 1

    func contains(s: String) -> Bool {
        return (self.range(of: s) != nil) ? true : false

Swift 2.2:

extension String {    
    var length:Int {
        return self.characters.count

    func indexOf(target: String) -> Int? {

        let range = (self as NSString).rangeOfString(target)

        guard range.toRange() != nil else {
            return nil

        return range.location

    func lastIndexOf(target: String) -> Int? {

        let range = (self as NSString).rangeOfString(target, options: NSStringCompareOptions.BackwardsSearch)

        guard range.toRange() != nil else {
            return nil

        return self.length - range.location - 1

    func contains(s: String) -> Bool {
        return (self.rangeOfString(s) != nil) ? true : false

add maven repository to build.gradle

You will need to define the repository outside of buildscript. The buildscript configuration block only sets up the repositories and dependencies for the classpath of your build script but not your application.

T-SQL stored procedure that accepts multiple Id values

A superfast XML Method, if you want to use a stored procedure and pass the comma separated list of Department IDs :

Declare @XMLList xml
SET @XMLList=cast('<i>'+replace(@DepartmentIDs,',','</i><i>')+'</i>' as xml)
SELECT x.i.value('.','varchar(5)') from @XMLList.nodes('i') x(i))

All credit goes to Guru Brad Schulz's Blog

Resize UIImage and change the size of UIImageView

Use the category below and then apply border from Quartz into your image:

[yourimage.layer setBorderColor:[[UIColor whiteColor] CGColor]];
[yourimage.layer setBorderWidth:2];

The category: UIImage+AutoScaleResize.h

#import <Foundation/Foundation.h>

@interface UIImage (AutoScaleResize)

- (UIImage *)imageByScalingAndCroppingForSize:(CGSize)targetSize;



#import "UIImage+AutoScaleResize.h"

@implementation UIImage (AutoScaleResize)

- (UIImage *)imageByScalingAndCroppingForSize:(CGSize)targetSize
    UIImage *sourceImage = self;
    UIImage *newImage = nil;
    CGSize imageSize = sourceImage.size;
    CGFloat width = imageSize.width;
    CGFloat height = imageSize.height;
    CGFloat targetWidth = targetSize.width;
    CGFloat targetHeight = targetSize.height;
    CGFloat scaleFactor = 0.0;
    CGFloat scaledWidth = targetWidth;
    CGFloat scaledHeight = targetHeight;
    CGPoint thumbnailPoint = CGPointMake(0.0,0.0);

    if (CGSizeEqualToSize(imageSize, targetSize) == NO)
        CGFloat widthFactor = targetWidth / width;
        CGFloat heightFactor = targetHeight / height;

        if (widthFactor > heightFactor)
            scaleFactor = widthFactor; // scale to fit height
            scaleFactor = heightFactor; // scale to fit width

        scaledWidth  = width * scaleFactor;
        scaledHeight = height * scaleFactor;

        // center the image
        if (widthFactor > heightFactor)
            thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
            if (widthFactor < heightFactor)
                thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;

    UIGraphicsBeginImageContext(targetSize); // this will crop

    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = thumbnailPoint;
    thumbnailRect.size.width  = scaledWidth;
    thumbnailRect.size.height = scaledHeight;

    [sourceImage drawInRect:thumbnailRect];

    newImage = UIGraphicsGetImageFromCurrentImageContext();

    if(newImage == nil)
        NSLog(@"could not scale image");

    //pop the context to get back to the default

    return newImage;


Passing data to a bootstrap modal

Bootstrap 4.3 - use code from below snippet - more here

$('#exampleModal').on('', function (event) {_x000D_
  let bookId = $(event.relatedTarget).data('bookid') _x000D_
  $(this).find('.modal-body input').val(bookId)_x000D_
_x000D_ {color: white }
<!-- Initialize Bootstrap 4 -->_x000D_
<link rel="stylesheet" href="" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">_x000D_
<script src="" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>_x000D_
<script src="" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>_x000D_
<script src="" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>_x000D_
<!-- BUTTON -->_x000D_
<a _x000D_
  class="btn btn-primary open-AddBookDialog" _x000D_
  data-toggle="modal" _x000D_
  data-target="#exampleModal" _x000D_
  data-bookid="@book.Id" _x000D_
  title="Add this item"_x000D_
<!-- MODAL -->_x000D_
<div class="modal fade" id="exampleModal" tabindex="-1" role="dialog">_x000D_
  <div class="modal-dialog" role="document">_x000D_
    <div class="modal-content">_x000D_
      <div class="modal-body">_x000D_
        <input type="hidden" name="bookId" id="bookId" value=""/>_x000D_
        <input type="text" class="form-control" id="recipient-name">    _x000D_
      <div class="modal-footer">_x000D_
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>_x000D_

Delete a database in phpMyAdmin

Taking a queue from michael's answer above, I was unable to find the DROP Database command on my phpMyAdmin console in the localhost.

Apparantly I was missing a setting. Go to file of the phpMyAdmin folder, and add this:

$cfg['AllowUserDropDatabase'] = true;

Save and restart the local server and the command appears inside the console.

Resizing an Image without losing any quality

You can't resize an image without losing some quality, simply because you are reducing the number of pixels.

Don't reduce the size client side, because browsers don't do a good job of resizing images.

What you can do is programatically change the size before you render it, or as a user uploads it.

Here is an article that explains one way to do this in c#:

What is the single most influential book every programmer should read?

Beginning C# 3.0: An Introduction to Object Oriented Programming

This is the book for those who want to understand the whys and hows of OOP using C# 3.0. You don't want to miss it.

How to set a session variable when clicking a <a> link

I had the same problem - i wanted to pass a parameter to another page by clicking a hyperlink and get the value to go to the next page (without using GET because the parameter is stored in the URL).

to those who don't understand why you would want to do this the answer is you dont want the user to see sensitive information or you dont want someone editing the GET.

well after scouring the internet it seemed it wasnt possible to make a normal hyperlink using the POST method.

And then i had a eureka moment!!!! why not just use CSS to make the submit button look like a normal hyperlink??? ...and put the value i want to pass in a hidden field

i tried it and it works. you can see an exaple here

the basic code for the form is:

    <form enctype="multipart/form-data" action="page-to-pass-to.php" method="post">
                        <input type="hidden" name="post-variable-name" value="value-you-want-pass"/>
                        <input type="submit" name="whatever" value="text-to-display" id="hyperlink-style-button"/>

the basic css is:



What's the fastest way to read a text file line-by-line?

To find the fastest way to read a file line by line you will have to do some benchmarking. I have done some small tests on my computer but you cannot expect that my results apply to your environment.

Using StreamReader.ReadLine

This is basically your method. For some reason you set the buffer size to the smallest possible value (128). Increasing this will in general increase performance. The default size is 1,024 and other good choices are 512 (the sector size in Windows) or 4,096 (the cluster size in NTFS). You will have to run a benchmark to determine an optimal buffer size. A bigger buffer is - if not faster - at least not slower than a smaller buffer.

const Int32 BufferSize = 128;
using (var fileStream = File.OpenRead(fileName))
  using (var streamReader = new StreamReader(fileStream, Encoding.UTF8, true, BufferSize)) {
    String line;
    while ((line = streamReader.ReadLine()) != null)
      // Process line

The FileStream constructor allows you to specify FileOptions. For example, if you are reading a large file sequentially from beginning to end, you may benefit from FileOptions.SequentialScan. Again, benchmarking is the best thing you can do.

Using File.ReadLines

This is very much like your own solution except that it is implemented using a StreamReader with a fixed buffer size of 1,024. On my computer this results in slightly better performance compared to your code with the buffer size of 128. However, you can get the same performance increase by using a larger buffer size. This method is implemented using an iterator block and does not consume memory for all lines.

var lines = File.ReadLines(fileName);
foreach (var line in lines)
  // Process line

Using File.ReadAllLines

This is very much like the previous method except that this method grows a list of strings used to create the returned array of lines so the memory requirements are higher. However, it returns String[] and not an IEnumerable<String> allowing you to randomly access the lines.

var lines = File.ReadAllLines(fileName);
for (var i = 0; i < lines.Length; i += 1) {
  var line = lines[i];
  // Process line

Using String.Split

This method is considerably slower, at least on big files (tested on a 511 KB file), probably due to how String.Split is implemented. It also allocates an array for all the lines increasing the memory required compared to your solution.

using (var streamReader = File.OpenText(fileName)) {
  var lines = streamReader.ReadToEnd().Split("\r\n".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
  foreach (var line in lines)
    // Process line

My suggestion is to use File.ReadLines because it is clean and efficient. If you require special sharing options (for example you use FileShare.ReadWrite), you can use your own code but you should increase the buffer size.

How to check if image exists with given url?

Use Case



  var that=this;
  if($(that).attr('data-safeurl') && $(that).attr('data-safeurl') === 'found'){
        return that;

 return that;

Note : rm means here risk managment .

Another Use Case :

  • 'http://example/1.png' : if not exist 'http://example/2.png'

  • 'http://example/2.png' : if not exist 'http://example/3.png'

Selenium: WebDriverException:Chrome failed to start: crashed as google-chrome is no longer running so ChromeDriver is assuming that Chrome has crashed

This error has been happening randomly during my test runs over the last six months (still happens with Chrome 76 and Chromedriver 76) and only on Linux. On average one of every few hundred tests would fail, then the next test would run fine.

Unable to resolve the issue, in Python I wrapped the driver = webdriver.Chrome() in a try..except block in setUp() in my test case class that all my tests are derived from. If it hits the Webdriver exception it waits ten seconds and tries again.

It solved the issue I was having; not elegantly but it works.

from selenium import webdriver
from selenium.common.exceptions import WebDriverException

    self.driver = webdriver.Chrome(chrome_options=chrome_options, desired_capabilities=capabilities)
except WebDriverException as e:
    print("\nChrome crashed on launch:")
    print("Trying again in 10 seconds..")
    self.driver = webdriver.Chrome(chrome_options=chrome_options, desired_capabilities=capabilities)
except Exception as e:
    raise Exception(e)

Create ArrayList from array

Java 8’s Arrays class provides a stream() method which has overloaded versions accepting both primitive arrays and Object arrays.

/**** Converting a Primitive 'int' Array to List ****/

int intArray[] = {1, 2, 3, 4, 5};

List<Integer> integerList1 =;

/**** 'IntStream.of' or '' Gives The Same Output ****/

List<Integer> integerList2 = IntStream.of(intArray).boxed().collect(Collectors.toList());

/**** Converting an 'Integer' Array to List ****/

Integer integerArray[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

List<Integer> integerList3 =;

How to bundle vendor scripts separately and require them as needed with Webpack?

in my webpack.config.js (Version 1,2,3) file, I have

function isExternal(module) {
  var context = module.context;

  if (typeof context !== 'string') {
    return false;

  return context.indexOf('node_modules') !== -1;

in my plugins array

plugins: [
  new CommonsChunkPlugin({
    name: 'vendors',
    minChunks: function(module) {
      return isExternal(module);
  // Other plugins

Now I have a file that only adds 3rd party libs to one file as required.

If you want get more granular where you separate your vendors and entry point files:

plugins: [
  new CommonsChunkPlugin({
    name: 'common',
    minChunks: function(module, count) {
      return !isExternal(module) && count >= 2; // adjustable
  new CommonsChunkPlugin({
    name: 'vendors',
    chunks: ['common'],
    // or if you have an key value object for your entries
    // chunks: Object.keys(entry).concat('common')
    minChunks: function(module) {
      return isExternal(module);

Note that the order of the plugins matters a lot.

Also, this is going to change in version 4. When that's official, I update this answer.

Update: indexOf search change for windows users

NUnit Unit tests not showing in Test Explorer with Test Adapter installed

If you're using a NUnit3+ version, there is a new Test Adapter available.

Go to "Tools -> Extensions and Updates -> Online" and search for "NUnit3 Test Adapter" and then install.

Lodash - difference between .extend() / .assign() and .merge()

It might be also helpful to consider what they do from a semantic point of view:


   will assign the values of the properties of its second parameter and so on,
   as properties with the same name of the first parameter. (shallow copy & override)


   merge is like assign but does not assign objects but replicates them instead.
  (deep copy)


   provides default values for missing values.
   so will assign only values for keys that do not exist yet in the source.


   works like _defaults but like merge will not simply copy objects
   and will use recursion instead.

I believe that learning to think of those methods from the semantic point of view would let you better "guess" what would be the behavior for all the different scenarios of existing and non existing values.

hide/show a image in jquery

I know this is an older post but it may be useful for those who are looking to show a .NET server side image using jQuery.

You have to use a slightly different logic.

So, $("#<%=myServerimg.ClientID%>").show() will not work if you hid the image using myServerimg.visible = false.

Instead, use the following on server side:

myServerimg.Style.Add("display", "none")

Selenium WebDriver How to Resolve Stale Element Reference Exception?

In Selenium 3, you can use ExpectedConditions.refreshed(your condition).

It will handle the StaleElementReferenceException and retry the condition.

mysqldump exports only one table

In case you encounter an error like this

mysqldump: 1044 Access denied when using LOCK TABLES

A quick workaround is to pass the –-single-transaction option to mysqldump.

So your command will be like this.

mysqldump --single-transaction -u user -p DBNAME > backup.sql

ImageView in android XML layout with layout_height="wrap_content" has padding top & bottom

I had a simular issue and resolved it using android:adjustViewBounds="true" on the ImageView.

    android:src="@drawable/banner_portrait" />

SQL DATEPART(dw,date) need monday = 1 and sunday = 7

Another solution is the following:


What exceptions should be thrown for invalid or unexpected parameters in .NET?

There is a standard ArgumentException that you could use, or you could subclass and make your own. There are several specific ArgumentException classes:

Whichever one works best.

How to capture the "virtual keyboard show/hide" event in Android?

I have sort of a hack to do this. Although there doesn't seem to be a way to detect when the soft keyboard has shown or hidden, you can in fact detect when it is about to be shown or hidden by setting an OnFocusChangeListener on the EditText that you're listening to.

EditText et = (EditText) findViewById(;
et.setOnFocusChangeListener(new View.OnFocusChangeListener()
        public void onFocusChange(View view, boolean hasFocus)
            //hasFocus tells us whether soft keyboard is about to show

NOTE: One thing to be aware of with this hack is that this callback is fired immediately when the EditText gains or loses focus. This will actually fire right before the soft keyboard shows or hides. The best way I've found to do something after the keyboard shows or hides is to use a Handler and delay something ~ 400ms, like so:

EditText et = (EditText) findViewById(;
et.setOnFocusChangeListener(new View.OnFocusChangeListener()
        public void onFocusChange(View view, boolean hasFocus)
            new Handler().postDelayed(new Runnable()
                    public void run()
                        //do work here
                }, 400);

Iterate over the lines of a string

I suppose you could roll your own:

def parse(string):
    retval = ''
    for char in string:
        retval += char if not char == '\n' else ''
        if char == '\n':
            yield retval
            retval = ''
    if retval:
        yield retval

I'm not sure how efficient this implementation is, but that will only iterate over your string once.

Mmm, generators.


Of course you'll also want to add in whatever type of parsing actions you want to take, but that's pretty simple.

javascript create array from for loop

var yearStart = 2000;
var yearEnd = 2040;

var arr = [];

for (var i = yearStart; i <= yearEnd; i++) {


Simple VBA selection: Selecting 5 cells to the right of the active cell

This example selects a new Range of Cells defined by the current cell to a cell 5 to the right.

Note that .Offset takes arguments of Offset(row, columns) and can be quite useful.

Sub testForStackOverflow()
    Range(ActiveCell, ActiveCell.Offset(0, 5)).Copy
End Sub

What are the ways to make an html link open a folder

You can also copy the link address and paste it in a new window to get around the security. This works in chrome and firefox but you may have to add slashes in firefox.

How can I run a PHP script in the background after a form is submitted?

Background cron job sounds like a good idea for this.

You'll need ssh access to the machine to run the script as a cron.

$ php scriptname.php to run it.

Is there a way to provide named parameters in a function call in JavaScript?

Trying Node-6.4.0 ( process.versions.v8 = '') and Node Chakracore-v7.0.0-pre8 and then Chrome-52 (V8=5.2.361.49), I've noticed that named parameters are almost implemented, but that order has still precedence. I can't find what the ECMA standard says.

>function f(a=1, b=2){ console.log(`a=${a} + b=${b} = ${a+b}`) }

> f()
a=1 + b=2 = 3
> f(a=5)
a=5 + b=2 = 7
> f(a=7, b=10)
a=7 + b=10 = 17

But order is required!! Is it the standard behaviour?

> f(b=10)
a=10 + b=2 = 12

Generate PDF from Swagger API documentation

Handy way: Using Browser Printing/Preview

  1. Hide editor pane
  2. Print Preview (I used firefox, others also fine)
  3. Change its page setup and print to pdf

enter image description here

how to check if a file is a directory or regular file in python?

An educational example from the stat documentation:

import os, sys
from stat import *

def walktree(top, callback):
    '''recursively descend the directory tree rooted at top,
       calling the callback function for each regular file'''

    for f in os.listdir(top):
        pathname = os.path.join(top, f)
        mode = os.stat(pathname)[ST_MODE]
        if S_ISDIR(mode):
            # It's a directory, recurse into it
            walktree(pathname, callback)
        elif S_ISREG(mode):
            # It's a file, call the callback function
            # Unknown file type, print a message
            print 'Skipping %s' % pathname

def visitfile(file):
    print 'visiting', file

if __name__ == '__main__':
    walktree(sys.argv[1], visitfile)

Selenium WebDriver: I want to overwrite value in field instead of appending to it with sendKeys using Java

Had issues using most of the mentioned methods since textfield had not accepted keyboard input, and the mouse solution seem not complete.

This worked for to simulate a click in the field, selecting the content and replacing it with new.

     Actions actionList = new Actions(driver);

How to show soft-keyboard when edittext is focused

You can try to force the soft keyboard to appear, it works for me:

InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);

Resizing SVG in html?

I have found it best to add viewBox and preserveAspectRatio attributes to my SVGs. The viewbox should describe the full width and height of the SVG in the form 0 0 w h:

<svg preserveAspectRatio="xMidYMid meet" viewBox="0 0 700 550"></svg>

Server Discovery And Monitoring engine is deprecated

if you used typescript add config to the MongoOptions

const MongoOptions: MongoClientOptions = {
  useNewUrlParser: true,
  useUnifiedTopology: true,

      const client = await MongoClient.connect(url, MongoOptions);

if you not used typescript  
const MongoOptions= {
  useNewUrlParser: true,
  useUnifiedTopology: true,

How to get option text value using AngularJS?

Also you can do like this:

<select class="form-control postType" ng-model="selectedProd">
    <option ng-repeat="product in productList" value="{{product}}">{{}}</option>

where "selectedProd" will be selected product.

New line in Sql Query

-- Access: 
SELECT CHR(13) & CHR(10) 

-- SQL Server: 

What do "branch", "tag" and "trunk" mean in Subversion repositories?

In general (tool agnostic view), a branch is the mechanism used for parallel development. An SCM can have from 0 to n branches. Subversion has 0.

  • Trunk is a main branch recommended by Subversion, but you are in no way forced to create it. You could call it 'main' or 'releases', or not have one at all!

  • Branch represents a development effort. It should never be named after a resource (like 'vonc_branch') but after:

    • a purpose 'myProject_dev' or 'myProject_Merge'
    • a release perimeter 'myProjetc1.0_dev'or myProject2.3_Merge' or 'myProject6..2_Patch1'...
  • Tag is a snapshot of files in order to easily get back to that state. The problem is that tag and branch is the same in Subversion. And I would definitely recommend the paranoid approach:

    you can use one of the access control scripts provided with Subversion to prevent anyone from doing anything but creating new copies in the tags area.

A tag is final. Its content should never change. NEVER. Ever. You forgot a line in the release note? Create a new tag. Obsolete or remove the old one.

Now, I read a lot about "merging back such and such in such and such branches, then finally in the trunk branch". That is called merge workflow and there is nothing mandatory here. It is not because you have a trunk branch that you have to merge back anything.

By convention, the trunk branch can represent the current state of your development, but that is for a simple sequential project, that is a project which has:

  • no 'in advance' development (for the preparing the next-next version implying such changes that they are not compatible with the current 'trunk' development)
  • no massive refactoring (for testing a new technical choice)
  • no long-term maintenance of a previous release

Because with one (or all) of those scenario, you get yourself four 'trunks', four 'current developments', and not all you do in those parallel development will necessarily have to be merged back in 'trunk'.

How To Format A Block of Code Within a Presentation?

If you write your code in emacs then you might be interested in the htmlize elisp package.