Programs & Examples On #Glow

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

Below is the code that Bootstrap uses. Colors are bit different but the concept is same. This is if you are using LESS to compile CSS:

// Form control focus state
// Generate a customized focus state and for any input with the specified color,
// which defaults to the `@input-focus-border` variable.
// We highly encourage you to not customize the default value, but instead use
// this to tweak colors on an as-needed basis. This aesthetic change is based on
// WebKit's default styles, but applicable to a wider range of browsers. Its
// usability and accessibility should be taken into account with any change.
// Example usage: change the default blue border and shadow to white for better
// contrast against a dark gray background.

.form-control-focus(@color: @input-border-focus) {
  @color-rgba: rgba(red(@color), green(@color), blue(@color), .6);
  &:focus {
    border-color: @color;
    outline: 0;
    .box-shadow(~"inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px @{color-rgba}");

If you are not using LESS then here's the compiled version:

.form-control:focus {
    border-color: #66afe9;
    outline: 0;
    -webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
    box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);

CSS: create white glow around image

Depends on what your target browsers are. In newer ones it's as simple as:

   -moz-box-shadow: 0 0 5px #fff;
-webkit-box-shadow: 0 0 5px #fff;
        box-shadow: 0 0 5px #fff;

For older browsers you have to implement workarounds, e.g., based on this example, but you will most probably need extra mark-up.

Enabling refreshing for specific html elements only

Try this:

function reload(){_x000D_
    var container = document.getElementById("yourDiv");_x000D_
    var content = container.innerHTML;_x000D_
    container.innerHTML= content; _x000D_
   //this line is to watch the result in console , you can remove it later _x000D_
    console.log("Refreshed"); _x000D_
<a href="javascript: reload()">Click to Reload</a>_x000D_
    <div id="yourDiv">The content that you want to refresh/reload</div>

Hope it works. Let me know

Differences between "java -cp" and "java -jar"?

When using java -cp you are required to provide fully qualified main class name, e.g.

java -cp com.mycompany.MyMain

When using java -jar myjar.jar your jar file must provide the information about main class via contained into the jar file in folder META-INF:

Main-Class: com.mycompany.MyMain

Link to the issue number on GitHub within a commit message

In order to link the issue number to your commit message, you should add: #issue_number in your git commit message.

Example Commit Message from Udacity Git Commit Message Style Guide

feat: Summarize changes in around 50 characters or less

More detailed explanatory text, if necessary. Wrap it to about 72
characters or so. In some contexts, the first line is treated as the
subject of the commit and the rest of the text as the body. The
blank line separating the summary from the body is critical (unless
you omit the body entirely); various tools like `log`, `shortlog`
and `rebase` can get confused if you run the two together.

Explain the problem that this commit is solving. Focus on why you
are making this change as opposed to how (the code explains that).
Are there side effects or other unintuitive consequenses of this
change? Here's the place to explain them.

Further paragraphs come after blank lines.

 - Bullet points are okay, too

 - Typically a hyphen or asterisk is used for the bullet, preceded
   by a single space, with blank lines in between, but conventions
   vary here

If you use an issue tracker, put references to them at the bottom,
like this:

Resolves: #123
See also: #456, #789

You can also reference the repositories:


How to get a value inside an ArrayList java

main class

public class Test {
    public static void main (String [] args){
        Car thisCar= new Car ("Toyota", "$10000", "2003");  
        ArrayList<Car> car= new ArrayList<Car> ();

    public static void processCar(ArrayList<Car> car){
        for(Car c : car){
            System.out.println (c.getPrice());

car class

public class Car {
    private String vehicle;
    private String price;
    private String model;

    public Car(String vehicle, String price, String model){
        this.vehicle = vehicle;
        this.model = model;
        this.price = price;

    public String getVehicle() {
        return vehicle;

    public String getPrice() {
        return price;

    public String getModel() {
        return model;

Msg 102, Level 15, State 1, Line 1 Incorrect syntax near ' '

For the OP's command:

select compid,2, convert(datetime, '01/01/' + CONVERT(char(4),cal_yr) ,101) ,0,  Update_dt, th1, th2, th3_pc , Update_id, Update_dt,1
from  #tmp_CTF** 

I get this error:

Msg 102, Level 15, State 1, Line 2
Incorrect syntax near '*'.

when debugging something like this split the long line up so you'll get a better row number:

select compid
, convert(datetime
, '01/01/' 
+ CONVERT(char(4)
,  Update_dt
, th1
, th2
, th3_pc 
, Update_id
, Update_dt
from  #tmp_CTF** 

this now results in:

Msg 102, Level 15, State 1, Line 16
Incorrect syntax near '*'.

which is probably just from the OP not putting the entire command in the question, or use [ ] braces to signify the table name:

from [#tmp_CTF**]

if that is the table name.

postgresql - replace all instances of a string within text field

You can use the replace function

UPDATE your_table SET field = REPLACE(your_field, 'cat','dog')

The function definition is as follows (got from here):

replace(string text, from text, to text)

and returns the modified text. You can also check out this sql fiddle.

Sort Dictionary by keys

let dictionary = [
    "A" : [1, 2],
    "Z" : [3, 4],
    "D" : [5, 6]

let sortedKeys = Array(dictionary.keys).sorted(<) // ["A", "D", "Z"]


The sorted array from the above code contains keys only, while values have to be retrieved from the original dictionary. However, 'Dictionary' is also a 'CollectionType' of (key, value) pairs and we can use the global 'sorted' function to get a sorted array containg both keys and values, like this:

let sortedKeysAndValues = sorted(dictionary) { $0.0 < $1.0 }
println(sortedKeysAndValues) // [(A, [1, 2]), (D, [5, 6]), (Z, [3, 4])]

EDIT2: The monthly changing Swift syntax currently prefers

let sortedKeys = Array(dictionary.keys).sort(<) // ["A", "D", "Z"]

The global sorted is deprecated.

Escape double quote in VB string

Escaping quotes in VB6 or VBScript strings is simple in theory although often frightening when viewed. You escape a double quote with another double quote.

An example:

"c:\program files\my app\app.exe"

If I want to escape the double quotes so I could pass this to the shell execute function listed by Joe or the VB6 Shell function I would write it:

escapedString = """c:\program files\my app\app.exe"""

How does this work? The first and last quotes wrap the string and let VB know this is a string. Then each quote that is displayed literally in the string has another double quote added in front of it to escape it.

It gets crazier when you are trying to pass a string with multiple quoted sections. Remember, every quote you want to pass has to be escaped.

If I want to pass these two quoted phrases as a single string separated by a space (which is not uncommon):

"c:\program files\my app\app.exe" "c:\documents and settings\steve"

I would enter this:

escapedQuoteHell = """c:\program files\my app\app.exe"" ""c:\documents and settings\steve"""

I've helped my sysadmins with some VBScripts that have had even more quotes.

It's not pretty, but that's how it works.

What's the difference between lists enclosed by square brackets and parentheses in Python?

One interesting difference :

print lst          // prints [1]
print type(lst)    // prints <type 'list'>

print notATuple        // prints 1
print type(notATuple)  // prints <type 'int'>
                                         ^^ instead of tuple(expected)

A comma must be included in a tuple even if it contains only a single value. e.g. (1,) instead of (1).

Access host database from a docker container

From the 18.03 docs:

I want to connect from a container to a service on the host

The host has a changing IP address (or none if you have no network access). From 18.03 onwards our recommendation is to connect to the special DNS name host.docker.internal, which resolves to the internal IP address used by the host.

The gateway is also reachable as gateway.docker.internal.

EXAMPLE: Here's what I use for my MySQL connection string inside my container to access the MySQL instance on my host:


Create two threads, one display odd & other even numbers

package p.Threads;

public class PrintEvenAndOddNum  {

    private  Object obj = new Object();

    private static final PrintEvenAndOddNum peon = new PrintEvenAndOddNum();

    private PrintEvenAndOddNum(){}

    public static PrintEvenAndOddNum getInstance(){
        return peon;

    public  void printOddNum()  {
        for(int i=1;i<10;i++){
            if(i%2 != 0){
                synchronized (obj) {

                    try {
                        System.out.println("oddNum going into waiting state ....");

                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block

    public  void printEvenNum()  {
        for(int i=1;i<11;i++){
            if(i%2 == 0){
                    try {
                        System.out.println("evenNum going into waiting state ....");
                        System.out.println("Notifying waiting thread ....");
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block

Recursive search and replace in text files on Mac and Linux

The command on OSX should be exactly the same as it is Unix under the pretty UI.

How to include JavaScript file or library in Chrome console?

var el = document.createElement("script"),
loaded = false;
el.onload = el.onreadystatechange = function () {
  if ((el.readyState && el.readyState !== "complete" && el.readyState !== "loaded") || loaded) {
    return false;
  el.onload = el.onreadystatechange = null;
  loaded = true;
  // done!
el.async = true;
el.src = path;
var hhead = document.getElementsByTagName('head')[0];
hhead.insertBefore(el, hhead.firstChild);

How to use Comparator in Java to sort

Here's a super short template to do the sorting right away :

Collections.sort(people,new Comparator<Person>(){
   public int compare(final Person lhs,Person rhs) {
     //TODO return 1 if rhs should be before lhs 
     //     return -1 if lhs should be before rhs
     //     return 0 otherwise (meaning the order stays the same)

if it's hard to remember, try to just remember that it's similar (in terms of the sign of the number) to:


That's in case you want to sort in ascending order : from smallest number to largest number.

How to move all files including hidden files into parent directory via *

Let me introduce you to my friend "dotglob". It turns on and off whether or not "*" includes hidden files.

$ mkdir test
$ cd test
$ touch a b c .hidden .hi .den
$ ls -a
. ..  .den  .hi .hidden a b c

$ shopt -u dotglob
$ ls *
a b c
$ for i in * ; do echo I found: $i ; done
I found: a
I found: b
I found: c

$ shopt -s dotglob
$ ls *
.den  .hi .hidden a b c
$ for i in * ; do echo I found: $i ; done
I found: .den
I found: .hi
I found: .hidden
I found: a
I found: b
I found: c

It defaults to "off".

$ shopt dotglob
dotglob         off

It is best to turn it back on when you are done otherwise you will confuse things that assume it will be off.

jQuery UI Dialog individual CSS styling

The standard way to do this is with jQuery UI's CSS Scopes:

<div class="myCssScope">
   <!-- dialog goes here -->

Unfortunately, the jQuery UI dialog moves the dialog DOM elements to the end of the document, to fix potential z-index issues. This means the scoping won't work (it will no longer have a ".myCssScope" ancestor).

Christoph Herold designed a workaround which I've implemented as a jQuery plugin, maybe that will help.

Firebase: how to generate a unique numeric ID for key?

I'd suggest reading through the Firebase documentation. Specifically, see the Saving Data portion of the Firebase JavaScript Web Guide.

From the guide:

Getting the Unique ID Generated by push()

Calling push() will return a reference to the new data path, which you can use to get the value of its ID or set data to it. The following code will result in the same data as the above example, but now we'll have access to the unique push ID that was generated

// Generate a reference to a new location and add some data using push()
var newPostRef = postsRef.push({
 author: "gracehop",
 title: "Announcing COBOL, a New Programming Language"

// Get the unique ID generated by push() by accessing its key
var postID = newPostRef.key;


  • A push generates a new data path, with a server timestamp as its key. These keys look like -JiGh_31GA20JabpZBfa, so not numeric.
  • If you wanted to make a numeric only ID, you would make that a parameter of the object to avoid overwriting the generated key.
    • The keys (the paths of the new data) are guaranteed to be unique, so there's no point in overwriting them with a numeric key.
    • You can instead set the numeric ID as a child of the object.
    • You can then query objects by that ID child using Firebase Queries.

From the guide:

In JavaScript, the pattern of calling push() and then immediately calling set() is so common that we let you combine them by just passing the data to be set directly to push() as follows. Both of the following write operations will result in the same data being saved to Firebase:

// These two methods are equivalent:
  author: "gracehop",
  title: "Announcing COBOL, a New Programming Language"
  author: "gracehop",
  title: "Announcing COBOL, a New Programming Language"


Automatic date update in a cell when another cell's value changes (as calculated by a formula)

You could fill the dependend cell (D2) by a User Defined Function (VBA Macro Function) that takes the value of the C2-Cell as input parameter, returning the current date as ouput.

Having C2 as input parameter for the UDF in D2 tells Excel that it needs to reevaluate D2 everytime C2 changes (that is if auto-calculation of formulas is turned on for the workbook).


Here is some code:

For the UDF:

    Public Function UDF_Date(ByVal data) As Date

        UDF_Date = Now()

    End Function

As Formula in D2:


You will have to give the D2-Cell a Date-Time Format, or it will show a numeric representation of the date-value.

And you can expand the formula over the desired range by draging it if you keep the C2 reference in the D2-formula relative.

Note: This still might not be the ideal solution because every time Excel recalculates the workbook the date in D2 will be reset to the current value. To make D2 only reflect the last time C2 was changed there would have to be some kind of tracking of the past value(s) of C2. This could for example be implemented in the UDF by providing also the address alonside the value of the input parameter, storing the input parameters in a hidden sheet, and comparing them with the previous values everytime the UDF gets called.


Here is a sample implementation of an UDF that tracks the changes of the cell values and returns the date-time when the last changes was detected. When using it, please be aware that:

  • The usage of the UDF is the same as described above.

  • The UDF works only for single cell input ranges.

  • The cell values are tracked by storing the last value of cell and the date-time when the change was detected in the document properties of the workbook. If the formula is used over large datasets the size of the file might increase considerably as for every cell that is tracked by the formula the storage requirements increase (last value of cell + date of last change.) Also, maybe Excel is not capable of handling very large amounts of document properties and the code might brake at a certain point.

  • If the name of a worksheet is changed all the tracking information of the therein contained cells is lost.

  • The code might brake for cell-values for which conversion to string is non-deterministic.

  • The code below is not tested and should be regarded only as proof of concept. Use it at your own risk.

    Public Function UDF_Date(ByVal inData As Range) As Date
        Dim wb As Workbook
        Dim dProps As DocumentProperties
        Dim pValue As DocumentProperty
        Dim pDate As DocumentProperty
        Dim sName As String
        Dim sNameDate As String
        Dim bDate As Boolean
        Dim bValue As Boolean
        Dim bChanged As Boolean
        bDate = True
        bValue = True
        bChanged = False
        Dim sVal As String
        Dim dDate As Date
        sName = inData.Address & "_" & inData.Worksheet.Name
        sNameDate = sName & "_dat"
        sVal = CStr(inData.Value)
        dDate = Now()
        Set wb = inData.Worksheet.Parent
        Set dProps = wb.CustomDocumentProperties
    On Error Resume Next
        Set pValue = dProps.Item(sName)
        If Err.Number <> 0 Then
            bValue = False
        End If
    On Error GoTo 0
        If Not bValue Then
            bChanged = True
            Set pValue = dProps.Add(sName, False, msoPropertyTypeString, sVal)
            bChanged = pValue.Value <> sVal
            If bChanged Then
                pValue.Value = sVal
            End If
        End If
    On Error Resume Next
        Set pDate = dProps.Item(sNameDate)
        If Err.Number <> 0 Then
            bDate = False
        End If
    On Error GoTo 0
        If Not bDate Then
            Set pDate = dProps.Add(sNameDate, False, msoPropertyTypeDate, dDate)
        End If
        If bChanged Then
            pDate.Value = dDate
            dDate = pDate.Value
        End If
        UDF_Date = dDate
     End Function

Make the insertion of the date conditional upon the range.

This has an advantage of not changing the dates unless the content of the cell is changed, and it is in the range C2:C2, even if the sheet is closed and saved, it doesn't recalculate unless the adjacent cell changes.

Adapted from this tip and @Paul S answer

Private Sub Worksheet_Change(ByVal Target As Range)
 Dim R1 As Range
 Dim R2 As Range
 Dim InRange As Boolean
    Set R1 = Range(Target.Address)
    Set R2 = Range("C2:C20")
    Set InterSectRange = Application.Intersect(R1, R2)

  InRange = Not InterSectRange Is Nothing
     Set InterSectRange = Nothing
   If InRange = True Then
     R1.Offset(0, 1).Value = Now()
   End If
     Set R1 = Nothing
     Set R2 = Nothing
 End Sub

Convert datetime to Unix timestamp and convert it back in python

def dt2ts(dt, utc=False):
    if utc:
        return calendar.timegm(dt.timetuple())
    if dt.tzinfo is None:
        return int(time.mktime(dt.timetuple()))
    utc_dt = dt.astimezone(tz.tzutc()).timetuple()
    return calendar.timegm(utc_dt)

If you want UTC timestamp :time.mktime just for local dt .Use calendar.timegm is safe but dt must the utc zone so change the zone to utc. If dt in UTC just use calendar.timegm.

What are and

DEVELOPER runs autoconf and automake:

  1. autoconf -- creates shippable configure script
    (which the installer will later run to make the Makefile)
  1. automake - creates shippable data file
    (which configure will later read to make the Makefile)

INSTALLER runs configure, make and sudo make install:

./configure       # Creates  Makefile        (from  
make              # Creates  the application (from the Makefile just created).  

sudo make install # Installs the application 
                  #   Often, by default its files are installed into /usr/local


Notation below is roughly: inputs --> programs --> outputs

DEVELOPER runs these: -> autoconf -> configure (script) --- (*.ac = autoconf) --> autoconf -> configure (script) --- ( depreciated. Use -> automake -> ----------- (*.am = automake)

INSTALLER runs these: -> configure -> Makefile (*.in = input file)

Makefile -> make ----------> (puts new software in your downloads or temporary directory)
Makefile -> make install -> (puts new software in system directories)

"autoconf is an extensible package of M4 macros that produce shell scripts to automatically configure software source code packages. These scripts can adapt the packages to many kinds of UNIX-like systems without manual user intervention. Autoconf creates a configuration script for a package from a template file that lists the operating system features that the package can use, in the form of M4 macro calls."

"automake is a tool for automatically generating files compliant with the GNU Coding Standards. Automake requires the use of Autoconf."


Free online tutorials:


The main used to build LibreOffice is over 12k lines of code, (but there are also 57 other files in subfolders.)

From this my generated configure is over 41k lines of code.

And while the and Makefile are both only 493 lines of code. (But, there are also 768 more's in subfolders.)

In Oracle, is it possible to INSERT or UPDATE a record through a view?

Views in Oracle may be updateable under specific conditions. It can be tricky, and usually is not advisable.

From the Oracle 10g SQL Reference:

Notes on Updatable Views

An updatable view is one you can use to insert, update, or delete base table rows. You can create a view to be inherently updatable, or you can create an INSTEAD OF trigger on any view to make it updatable.

To learn whether and in what ways the columns of an inherently updatable view can be modified, query the USER_UPDATABLE_COLUMNS data dictionary view. The information displayed by this view is meaningful only for inherently updatable views. For a view to be inherently updatable, the following conditions must be met:

  • Each column in the view must map to a column of a single table. For example, if a view column maps to the output of a TABLE clause (an unnested collection), then the view is not inherently updatable.
  • The view must not contain any of the following constructs:
    • A set operator
    • a DISTINCT operator
    • An aggregate or analytic function
    • A collection expression in a SELECT list
    • A subquery in a SELECT list
    • A subquery designated WITH READ ONLY
    • Joins, with some exceptions, as documented in Oracle Database Administrator's Guide

In addition, if an inherently updatable view contains pseudocolumns or expressions, then you cannot update base table rows with an UPDATE statement that refers to any of these pseudocolumns or expressions.

If you want a join view to be updatable, then all of the following conditions must be true:

  • The DML statement must affect only one table underlying the join.
  • For an INSERT statement, the view must not be created WITH CHECK OPTION, and all columns into which values are inserted must come from a key-preserved table. A key-preserved table is one for which every primary key or unique key value in the base table is also unique in the join view.
  • For an UPDATE statement, all columns updated must be extracted from a key-preserved table. If the view was created WITH CHECK OPTION, then join columns and columns taken from tables that are referenced more than once in the view must be shielded from UPDATE.
  • For a DELETE statement, if the join results in more than one key-preserved table, then Oracle Database deletes from the first table named in the FROM clause, whether or not the view was created WITH CHECK OPTION.

New to unit testing, how to write great tests?

Unit testing is about the output you get from a function/method/application. It does not matter at all how the result is produced, it just matters that it is correct. Therefore, your approach of counting calls to inner methods and such is wrong. What I tend to do is sit down and write what a method should return given certain input values or a certain environment, then write a test which compares the actual value returned with what I came up with.

Steps to upload an iPhone application to the AppStore

Apple provides detailed, illustrated instructions covering every step of the process. Log in to the iPhone developer site and click the "program portal" link. In the program portal you'll find a link to the program portal user's guide, which is a really good reference and guide on this topic.

How do you recursively unzip archives in a directory and its subdirectories from the Unix command-line?

I realise this is very old, but it was among the first hits on Google when I was looking for a solution to something similar, so I'll post what I did here. My scenario is slightly different as I basically just wanted to fully explode a jar, along with all jars contained within it, so I wrote the following bash functions:

function explode {
    local target="$1"
    echo "Exploding $target."
    if [ -f "$target" ] ; then
        explodeFile "$target"
    elif [ -d "$target" ] ; then
        while [ "$(find "$target" -type f -regextype posix-egrep -iregex ".*\.(zip|jar|ear|war|sar)")" != "" ] ; do
            find "$target" -type f -regextype posix-egrep -iregex ".*\.(zip|jar|ear|war|sar)" -exec bash -c 'source "<file-where-this-function-is-stored>" ; explode "{}"' \;
        echo "Could not find $target."

function explodeFile {
    local target="$1"
    echo "Exploding file $target."
    mv "$target" "$target.tmp"
    unzip -q "$target.tmp" -d "$target"
    rm "$target.tmp"

Note the <file-where-this-function-is-stored> which is needed if you're storing this in a file that is not read for a non-interactive shell as I happened to be. If you're storing the functions in a file loaded on non-interactive shells (e.g., .bashrc I believe) you can drop the whole source statement. Hopefully this will help someone.

A little warning - explodeFile also deletes the ziped file, you can of course change that by commenting out the last line.

Iterating Through a Dictionary in Swift

You can also use values.makeIterator() to iterate over dict values, like this:

for sb in sbItems.values.makeIterator(){
  // do something with your sb item..

You can also do the iteration like this, in a more swifty style:

  // $0 is your dict value..

sbItems is dict of type [String : NSManagedObject]

Header set Access-Control-Allow-Origin in .htaccess doesn't work

Just for the record, I was running into the exact same problem and none of the answers worked.

I used a headers checker tool:

I was testing with my IP ( and what came back was the following:

HTTP/1.1 301 Moved Permanently => 
Date => Sat, 10 Jan 2015 04:03:35 GMT
Server => Apache/2.2.21 (Win32) mod_ssl/2.2.21 OpenSSL/1.0.0e PHP/5.3.8 mod_perl/2.0.4 Perl/v5.10.1
Location =>
Content-Length => 380
Connection => close
Content-Type => text/html; charset=iso-8859-1

There was a redirection happening and the AJAX request does not honor/follow redirects.

It turned out to be the missing slash at the end of the domain (

I tested again with slash at the end and I got this below. Added a slash in the script too, and it was now working.

HTTP/1.1 200 OK => 
Date => Sat, 10 Jan 2015 04:03:53 GMT
Server => Apache/2.2.21 (Win32) mod_ssl/2.2.21 OpenSSL/1.0.0e PHP/5.3.8 mod_perl/2.0.4 Perl/v5.10.1
X-Powered-By => PHP/5.3.8
Access-Control-Allow-Origin => *
Access-Control-Allow-Methods => PUT, GET, POST, DELETE, OPTIONS
Access-Control-Allow-Headers => *
Content-Length => 1435
Connection => close
Content-Type => text/html

Use this tool to test if your headers are good and to troubleshoot what is happening.

How to fully delete a git repository created with init?

Windows cmd prompt: (You could try the below command directly in windows cmd if you are not comfortable with grep, rm -rf, find, xargs etc., commands in git bash )

Delete .git recursively inside the project folder by the following command in cmd:

FOR /F "tokens=*" %G IN ('DIR /B /AD /S .git') DO RMDIR /S /Q "%G"

How can I get the "network" time, (from the "Automatic" setting called "Use network-provided values"), NOT the time on the phone?

Now you can get time for the current location but for this you have to set the system's persistent default time zone.setTimeZone(String timeZone) which can be get from

Calendar calendar = Calendar.getInstance();
 long now = calendar.getTimeInMillis();
 TimeZone current = calendar.getTimeZone();

setAutoTimeEnabled(boolean enabled)

Sets whether or not wall clock time should sync with automatic time updates from NTP.

TimeManager timeManager = TimeManager.getInstance();
 // Use 24-hour time

 // Set clock time to noon
 Calendar calendar = Calendar.getInstance();
 calendar.set(Calendar.MILLISECOND, 0);
 calendar.set(Calendar.SECOND, 0);
 calendar.set(Calendar.MINUTE, 0);
 calendar.set(Calendar.HOUR_OF_DAY, 12);
 long timeStamp = calendar.getTimeInMillis();

I was looking for that type of answer I read your answer but didn't satisfied and it was bit old. I found the new solution and share it. :)

For more information visit:

Compiling with g++ using multiple cores

If using make, issue with -j. From man make:

  -j [jobs], --jobs[=jobs]
       Specifies the number of jobs (commands) to run simultaneously.  
       If there is more than one -j option, the last one is effective.
       If the -j option is given without an argument, make will not limit the
       number of jobs that can run simultaneously.

And most notably, if you want to script or identify the number of cores you have available (depending on your environment, and if you run in many environments, this can change a lot) you may use ubiquitous Python function cpu_count():

Like this:

make -j $(python3 -c 'import multiprocessing as mp; print(int(mp.cpu_count() * 1.5))')

If you're asking why 1.5 I'll quote user artless-noise in a comment above:

The 1.5 number is because of the noted I/O bound problem. It is a rule of thumb. About 1/3 of the jobs will be waiting for I/O, so the remaining jobs will be using the available cores. A number greater than the cores is better and you could even go as high as 2x.

Twitter Bootstrap Datepicker within modal window

Add z-indez in class ui-datepicker

    .ui-datepicker{ z-index:1151 !important; }

Cannot implicitly convert type 'string' to 'System.Threading.Tasks.Task<string>'

    public async Task<string> methodName()
             return Data;


Hope this helps :)

Hive load CSV with commas in quoted fields

ORG.APACHE.HADOOP.HIVE.SERDE2.OPENCSVSERDE Serde worked for me. My delimiter was '|' and one of the columns is enclosed in double quotes.


     "SEPARATORCHAR" = "|",
     "QUOTECHAR"     = "\"",
     "ESCAPECHAR"    = "\""
STORED AS TEXTFILE location '/user/abc/csv_folder';

Node Express sending image files as API response

a proper solution with streams and error handling is below:

const fs = require('fs')
const stream = require('stream')

app.get('/report/:chart_id/:user_id',(req, res) => {
  const r = fs.createReadStream('path to file') // or any other way to get a readable stream
  const ps = new stream.PassThrough() // <---- this makes a trick with stream error handling
   ps, // <---- this makes a trick with stream error handling
   (err) => {
    if (err) {
      console.log(err) // No such file or any other kind of error
      return res.sendStatus(400); 
  ps.pipe(res) // <---- this makes a trick with stream error handling

with Node older then 10 you will need to use pump instead of pipeline.

Append file contents to the bottom of existing file in Bash

This should work:

 cat "$API" >> "$CONFIG"

You need to use the >> operator to append to a file. Redirecting with > causes the file to be overwritten. (truncated).

How to fit Windows Form to any screen resolution?

int h = Screen.PrimaryScreen.WorkingArea.Height;
int w = Screen.PrimaryScreen.WorkingArea.Width;
this.ClientSize = new Size(w , h);

Why do access tokens expire?

In addition to the other responses:

Once obtained, Access Tokens are typically sent along with every request from Clients to protected Resource Servers. This induce a risk for access token stealing and replay (assuming of course that access tokens are of type "Bearer" (as defined in the initial RFC6750).

Examples of those risks, in real life:

  • Resource Servers generally are distributed application servers and typically have lower security levels compared to Authorization Servers (lower SSL/TLS config, less hardening, etc.). Authorization Servers on the other hand are usually considered as critical Security infrastructure and are subject to more severe hardening.

  • Access Tokens may show up in HTTP traces, logs, etc. that are collected legitimately for diagnostic purposes on the Resource Servers or clients. Those traces can be exchanged over public or semi-public places (bug tracers, service-desk, etc.).

  • Backend RS applications can be outsourced to more or less trustworthy third-parties.

The Refresh Token, on the other hand, is typically transmitted only twice over the wires, and always between the client and the Authorization Server: once when obtained by client, and once when used by client during refresh (effectively "expiring" the previous refresh token). This is a drastically limited opportunity for interception and replay.

Last thought, Refresh Tokens offer very little protection, if any, against compromised clients.

Dump a list in a pickle file and retrieve it back later

Pickling will serialize your list (convert it, and it's entries to a unique byte string), so you can save it to disk. You can also use pickle to retrieve your original list, loading from the saved file.

So, first build a list, then use pickle.dump to send it to a file...

Python 3.4.1 (default, May 21 2014, 12:39:51) 
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.2.79)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> mylist = ['I wish to complain about this parrot what I purchased not half an hour ago from this very boutique.', "Oh yes, the, uh, the Norwegian Blue...What's,uh...What's wrong with it?", "I'll tell you what's wrong with it, my lad. 'E's dead, that's what's wrong with it!", "No, no, 'e's uh,...he's resting."]
>>> import pickle
>>> with open('parrot.pkl', 'wb') as f:
...   pickle.dump(mylist, f)

Then quit and come back later… and open with pickle.load...

Python 3.4.1 (default, May 21 2014, 12:39:51) 
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.2.79)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pickle
>>> with open('parrot.pkl', 'rb') as f:
...   mynewlist = pickle.load(f)
>>> mynewlist
['I wish to complain about this parrot what I purchased not half an hour ago from this very boutique.', "Oh yes, the, uh, the Norwegian Blue...What's,uh...What's wrong with it?", "I'll tell you what's wrong with it, my lad. 'E's dead, that's what's wrong with it!", "No, no, 'e's uh,...he's resting."]

jQuery selector to get form by name

You have no combinator (space, >, +...) so no children will get involved, ever.

However, you could avoid the need for jQuery by using an ID and getElementById, or you could use the old getElementsByName("frmSave")[0] or the even older document.forms['frmSave']. jQuery is unnecessary here.

SQL where datetime column equals today's date?

Looks like you're using SQL Server, in which case GETDATE() or current_timestamp may help you. But you will have to ensure that the format of the date with which you are comparing the system dates matches (timezone, granularity etc.)


where convert(varchar(10), submission_date, 102) 
    = convert(varchar(10), getdate(), 102)

VBA Excel sort range by specific column

If the starting cell of the range and of the key is static, the solution can be very simple:

Range(Selection, Selection.End(xlToRight)).Select
Range(Selection, Selection.End(xlDown)).Select
Selection.Sort key1:=Range("B3", Range("B3").End(xlDown)), _
order1:=xlAscending, Header:=xlNo

Are there constants in JavaScript?

Are you trying to protect the variables against modification? If so, then you can use a module pattern:

var CONFIG = (function() {
     var private = {
         'MY_CONST': '1',
         'ANOTHER_CONST': '2'

     return {
        get: function(name) { return private[name]; }

alert('MY_CONST: ' + CONFIG.get('MY_CONST'));  // 1

alert('MY_CONST: ' + CONFIG.get('MY_CONST'));  // 1

CONFIG.private.MY_CONST = '2';                 // error
alert('MY_CONST: ' + CONFIG.get('MY_CONST'));  // 1

Using this approach, the values cannot be modified. But, you have to use the get() method on CONFIG :(.

If you don't need to strictly protect the variables value, then just do as suggested and use a convention of ALL CAPS.

insert password into database in md5 format?

if you want to use md5 encryptioon you can do it in your php script

$pass = $_GET['pass'];

$newPass = md5($pass)

and then insert it into the database that way, however MD5 is a one way encryption method and is near on impossible to decrypt without difficulty

How to return multiple rows from the stored procedure? (Oracle PL/SQL)

create procedure <procedure_name>(p_cur out sys_refcursor) as begin open p_cur for select * from <table_name> end;

how to get all markers on google-maps-v3

Google Maps API v3:

I initialized Google Map and added markers to it. Later, I wanted to retrieve all markers and did it simply by accessing the map property "markers".

var map = new GMaps({
    div: '#map',
    lat: 40.730610,
    lng: -73.935242,

var myMarkers = map.markers;

You can loop over it and access all Marker methods listed at Google Maps Reference.

How to exclude 0 from MIN formula Excel

Try this formula


Both SMALL and FREQUENCY functions accept "unions" as arguments, i.e. single cell references separated by commas and enclosed in brackets like (A1,C1,E1).

So the formula uses FREQUENCY and INDEX to find the number of zeroes in a range and if you add 1 to that you get the k value such that the kth smallest is always the minimum value excluding zero.

I'm assuming you don't have negative numbers.....

Center image in div horizontally

Every solution posted here assumes that you know the dimensions of your img, which is not a common scenario. Also, planting the dimensions into the solution is painful.

Simply set:

/* for the img inside your div */
display: block;
margin-left: auto;
margin-right: auto;


/* for the img inside your div */
display: block;
margin: 0 auto;

That's all.

Note, that you'll also have to set an initial min-width for your outer div.

Android emulator shows nothing except black screen and adb devices shows "device offline"

For me, I had to turned off both front and back camera. Hope this helps!


Here is a fairly easy to understand version using method syntax:

IEnumerable<JoinPair> outerLeft =
    lefts.SelectMany(l => 
        rights.Where(r => l.Key == r.Key)
              .DefaultIfEmpty(new Item())
              .Select(r => new JoinPair { LeftId = l.Id, RightId = r.Id }));

apply drop shadow to border-top only?

I find using these interactive tools help visualize what's happening, and whats possible

Edit: Check out the other tools for experimenting with the other generators and combinations. I have to remind myself sometimes that just because you can, doesn't mean you should - its easy to get carried away!

How to insert pandas dataframe via mysqldb into database?

This should do the trick:

import pandas as pd
import pymysql
from sqlalchemy import create_engine

# Create engine
engine = create_engine('mysql://USER_NAME_HERE:PASS_HERE@HOST_ADRESS_HERE/DB_NAME_HERE')

# Create the connection and close it(whether successed of failed)
with engine.begin() as connection:
  df.to_sql(name='INSERT_TABLE_NAME_HERE/INSERT_NEW_TABLE_NAME', con=connection, if_exists='append', index=False)

Javascript array declaration: new Array(), new Array(3), ['a', 'b', 'c'] create arrays that behave differently

Arrays have numerical indexes. So,

a = new Array();


b = new Array(2);

are not adding elements to the array, but adding .a1 and .a2 properties to the a object (arrays are objects too). As further evidence, if you did this:

a = new Array();
console.log(a.length);   // outputs zero because there are no items in the array

Your third option:


is assigning the variable c an array with three elements. Those three elements can be accessed as: c[0], c[1] and c[2]. In other words, c[0] === 'c1' and c.length === 3.

Javascript does not use its array functionality for what other languages call associative arrays where you can use any type of key in the array. You can implement most of the functionality of an associative array by just using an object in javascript where each item is just a property like this.

a = {};

It is generally a mistake to use an array for this purpose as it just confuses people reading your code and leads to false assumptions about how the code works.

FileNotFoundException while getting the InputStream object from HttpURLConnection

FileNotFound in this case means you got a 404 from your server

You Have to Set the Request Content-Type Header Parameter Set “content-type” request header to “application/json” to send the request content in JSON form.

This parameter has to be set to send the request body in JSON format.

Failing to do so, the server returns HTTP status code “400-bad request”.

con.setRequestProperty("Content-Type", "application/json; utf-8");

Full Script ->

public class SendDeviceDetails extends AsyncTask<String, Void, String> {

protected String doInBackground(String... params) {

    String data = "";
    String url = "";

    HttpURLConnection con = null;
    try {

        // From the above URL object,
        // we can invoke the openConnection method to get the HttpURLConnection object.
        // We can't instantiate HttpURLConnection directly, as it's an abstract class:
        con = (HttpURLConnection)new URL(url).openConnection();
        //To send a POST request, we'll have to set the request method property to POST:

        // Set the Request Content-Type Header Parameter
        // Set “content-type” request header to “application/json” to send the request content in JSON form.
        // This parameter has to be set to send the request body in JSON format.
        //Failing to do so, the server returns HTTP status code “400-bad request”.
        con.setRequestProperty("Content-Type", "application/json; utf-8");
        //Set Response Format Type
        //Set the “Accept” request header to “application/json” to read the response in the desired format:
        con.setRequestProperty("Accept", "application/json");

        //To send request content, let's enable the URLConnection object's doOutput property to true.
        //Otherwise, we'll not be able to write content to the connection output stream:

        //JSON String need to be constructed for the specific resource.
        //We may construct complex JSON using any third-party JSON libraries such as jackson or org.json
        String jsonInputString = params[0];

        try(OutputStream os = con.getOutputStream()){
            byte[] input = jsonInputString.getBytes("utf-8");
            os.write(input, 0, input.length);

        int code = con.getResponseCode();

        //Get the input stream to read the response content.
        // Remember to use try-with-resources to close the response stream automatically.
        try(BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(), "utf-8"))){
            StringBuilder response = new StringBuilder();
            String responseLine = null;
            while ((responseLine = br.readLine()) != null) {

    } catch (Exception e) {
    } finally {
        if (con != null) {

    return data;

protected void onPostExecute(String result) {
    Log.e("TAG", result); // this is expecting a response code to be sent from your server upon receiving the POST data

and call it

new SendDeviceDetails().execute("");

you can find more details in this tutorial

What does "The following object is masked from 'package:xxx'" mean?

The message means that both the packages have functions with the same names. In this particular case, the testthat and assertive packages contain five functions with the same name.

When two functions have the same name, which one gets called?

R will look through the search path to find functions, and will use the first one that it finds.

 ##  [1] ".GlobalEnv"        "package:assertive" "package:testthat" 
 ##  [4] "tools:rstudio"     "package:stats"     "package:graphics" 
 ##  [7] "package:grDevices" "package:utils"     "package:datasets" 
 ## [10] "package:methods"   "Autoloads"         "package:base"

In this case, since assertive was loaded after testthat, it appears earlier in the search path, so the functions in that package will be used.

## function (x, .xname = get_name_in_parent(x)) 
## {
##     x <- coerce_to(x, "logical", .xname)
##     call_and_name(function(x) {
##         ok <- x & !
##         set_cause(ok, ifelse(, "missing", "false"))
##     }, x)
## }
<bytecode: 0x0000000004fc9f10>
<environment: namespace:assertive.base>

The functions in testthat are not accessible in the usual way; that is, they have been masked.

What if I want to use one of the masked functions?

You can explicitly provide a package name when you call a function, using the double colon operator, ::. For example:

## function () 
## {
##     function(x) expect_true(x)
## }
## <environment: namespace:testthat>

How do I suppress the message?

If you know about the function name clash, and don't want to see it again, you can suppress the message by passing warn.conflicts = FALSE to library.

library(assertive, warn.conflicts = FALSE)
# No output this time

Alternatively, suppress the message with suppressPackageStartupMessages:

# Also no output

Impact of R's Startup Procedures on Function Masking

If you have altered some of R's startup configuration options (see ?Startup) you may experience different function masking behavior than you might expect. The precise order that things happen as laid out in ?Startup should solve most mysteries.

For example, the documentation there says:

Note that when the site and user profile files are sourced only the base package is loaded, so objects in other packages need to be referred to by e.g. utils::dump.frames or after explicitly loading the package concerned.

Which implies that when 3rd party packages are loaded via files like .Rprofile you may see functions from those packages masked by those in default packages like stats, rather than the reverse, if you loaded the 3rd party package after R's startup procedure is complete.

How do I list all the masked functions?

First, get a character vector of all the environments on the search path. For convenience, we'll name each element of this vector with its own value.

envs <- search() %>% setNames(., .)

For each environment, get the exported functions (and other variables).

fns <- lapply(envs, ls)

Turn this into a data frame, for easy use with dplyr.

fns_by_env <- data_frame(
  env =, lengths(fns)),
  fn  = unlist(fns)

Find cases where the object appears more than once.

fns_by_env %>% 
  group_by(fn) %>% 
  tally() %>% 
  filter(n > 1) %>% 

To test this, try loading some packages with known conflicts (e.g., Hmisc, AnnotationDbi).

How do I prevent name conflict bugs?

The conflicted package throws an error with a helpful error message, whenever you try to use a variable with an ambiguous name.

## Error: units found in 2 packages. You must indicate which one you want with ::
##  * Hmisc::units
##  * base::units

change image opacity using javascript

You can use CSS to set the opacity, and than use javascript to apply the styles to a certain element in the DOM.

.opClass {
    filter:alpha(opacity=40); /* For IE8 and earlier */

Than use (for example) jQuery to change the style:


Or with plain javascript, like this:

document.getElementById("element_id").className = "opClass";

How can I parse a String to BigDecimal?

Try this

// Create a DecimalFormat that fits your requirements
DecimalFormatSymbols symbols = new DecimalFormatSymbols();
String pattern = "#,##0.0#";
DecimalFormat decimalFormat = new DecimalFormat(pattern, symbols);

// parse the string
BigDecimal bigDecimal = (BigDecimal) decimalFormat.parse("10,692,467,440,017.120");

If you are building an application with I18N support you should use DecimalFormatSymbols(Locale)

Also keep in mind that decimalFormat.parse can throw a ParseException so you need to handle it (with try/catch) or throw it and let another part of your program handle it

Path to Powershell.exe (v 2.0)

It is always C:\Windows\System32\WindowsPowershell\v1.0. It was left like that for backward compability is what I heard or read somewhere.

SQL: How To Select Earliest Row

Simply use min()

SELECT company, workflow, MIN(date) 
FROM workflowTable 
GROUP BY company, workflow

How to convert java.lang.Object to ArrayList?

An interesting note: it appears that attempting to cast from an object to a list on the JavaFX Application thread always results in a ClassCastException.

I had the same issue as you, and no answer helped. After playing around for a while, the only thing I could narrow it down to was the thread. Running the code to cast on any other thread other than the UI thread succeeds as expected, and as the other answers in this section suggest.

Thus, be careful that your source isn't running on the JavaFX application thread.

How can I use inverse or negative wildcards when pattern matching in a unix/linux shell?

If you want to avoid the mem cost of using the exec command, I believe you can do better with xargs. I think the following is a more efficient alternative to

find foo -type f ! -name '*Music*' -exec cp {} bar \; # new proc for each exec

find . -maxdepth 1 -name '*Music*' -prune -o -print0 | xargs -0 -i cp {} dest/

Bootstrap Carousel Full Screen

I found an answer on the Try this code:


body {
    height: 100%;

.active {
    height: 100%;

.carousel-inner {
    height: 100%;

/* Background images are set within the HTML using inline CSS, not here */

.fill {
    width: 100%;
    height: 100%;
    background-position: center;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    background-size: cover;
    -o-background-size: cover;

footer {
    margin: 50px 0;


   <div class="carousel-inner">
        <div class="item active">
            <!-- Set the first background image using inline CSS below. -->
            <div class="fill" style="background-image:url(' One');"></div>
            <div class="carousel-caption">
                <h2>Caption 1</h2>
        <div class="item">
            <!-- Set the second background image using inline CSS below. -->
            <div class="fill" style="background-image:url(' Two');"></div>
            <div class="carousel-caption">
                <h2>Caption 2</h2>
        <div class="item">
            <!-- Set the third background image using inline CSS below. -->
            <div class="fill" style="background-image:url(' Three');"></div>
            <div class="carousel-caption">
                <h2>Caption 3</h2>


SQL like search string starts with

You need to use the wildcard % :

SELECT * from games WHERE (lower(title) LIKE 'age of empires III%');

How to perform case-insensitive sorting in JavaScript?

  function(a, b) {
    if (a.toLowerCase() < b.toLowerCase()) return -1;
    if (a.toLowerCase() > b.toLowerCase()) return 1;
    return 0;

EDIT: Please note that I originally wrote this to illustrate the technique rather than having performance in mind. Please also refer to answer @Ivan Krechetov for a more compact solution.

How to display images from a folder using php - PHP

You had a mistake on the statement below. Use . not ,

echo '<img src="', $dir, '/', $file, '" alt="', $file, $


echo '<img src="'. $dir. '/'. $file. '" alt="'. $file. $


echo 'Directory \'', $dir, '\' not found!';


echo 'Directory \''. $dir. '\' not found!';

LINQ: Select where object does not contain items from list

dump this into a more specific collection of just the ids you don't want

var notTheseBarIds = filterBars.Select(fb => fb.BarId);

then try this:

fooSelect = (from f in fooBunch
             where !notTheseBarIds.Contains(f.BarId)
             select f).ToList();

or this:

fooSelect = fooBunch.Where(f => !notTheseBarIds.Contains(f.BarId)).ToList();

What is the difference between the dot (.) operator and -> in C++?

Dot operator can't be overloaded, arrow operator can be overloaded. Arrow operator is generally meant to be applied to pointers (or objects that behave like pointers, like smart pointers). Dot operator can't be applied to pointers.

EDIT When applied to pointer arrow operator is equivalent to applying dot operator to pointee e.g. ptr->field is equivalent to (*ptr).field.

z-index not working with fixed positioning

This question can be solved in a number of ways, but really, knowing the stacking rules allows you to find the best answer that works for you.


The <html> element is your only stacking context, so just follow the stacking rules inside a stacking context and you will see that elements are stacked in this order

  1. The stacking context’s root element (the <html> element in this case)
  2. Positioned elements (and their children) with negative z-index values (higher values are stacked in front of lower values; elements with the same value are stacked according to appearance in the HTML)
  3. Non-positioned elements (ordered by appearance in the HTML)
  4. Positioned elements (and their children) with a z-index value of auto (ordered by appearance in the HTML)
  5. Positioned elements (and their children) with positive z-index values (higher values are stacked in front of lower values; elements with the same value are stacked according to appearance in the HTML)

So you can

  1. set a z-index of -1, for #under positioned -ve z-index appear behind non-positioned #over element
  2. set the position of #over to relative so that rule 5 applies to it

The Real Problem

Developers should know the following before trying to change the stacking order of elements.

  1. When a stacking context is formed
    • By default, the <html> element is the root element and is the first stacking context
  2. Stacking order within a stacking context

The Stacking order and stacking context rules below are from this link

When a stacking context is formed

  • When an element is the root element of a document (the <html> element)
  • When an element has a position value other than static and a z-index value other than auto
  • When an element has an opacity value less than 1
  • Several newer CSS properties also create stacking contexts. These include: transforms, filters, css-regions, paged media, and possibly others.
  • As a general rule, it seems that if a CSS property requires rendering in an offscreen context, it must create a new stacking context.

Stacking Order within a Stacking Context

The order of elements:

  1. The stacking context’s root element (the <html> element is the only stacking context by default, but any element can be a root element for a stacking context, see rules above)
    • You cannot put a child element behind a root stacking context element
  2. Positioned elements (and their children) with negative z-index values (higher values are stacked in front of lower values; elements with the same value are stacked according to appearance in the HTML)
  3. Non-positioned elements (ordered by appearance in the HTML)
  4. Positioned elements (and their children) with a z-index value of auto (ordered by appearance in the HTML)
  5. Positioned elements (and their children) with positive z-index values (higher values are stacked in front of lower values; elements with the same value are stacked according to appearance in the HTML)

Google access token expiration time

From Google OAuth2.0 for Client documentation,

  • expires_in -- The number of seconds left before the token becomes invalid.

Adding Multiple Values in ArrayList at a single index

How about

  1. First adding your desired result as arraylist and
  2. and convert to double array as you want.

Try like this..

import java.util.ArrayList;
import java.util.List;

    public class ArrayTest {

         * @param args
        public static void main(String[] args) {
            // TODO Auto-generated method stub

            // Your Prepared data. 
            List<double[]> values = new ArrayList<double[]>(2);

            double[] element1 = new double[] { 100, 100, 100, 100, 100 };
            double[] element2 = new double[] { 50, 35, 25, 45, 65 };


            // Add the result to arraylist.
            List<Double> temp = new ArrayList<Double>();
            for(int j=0;j<values.size(); j++) {
                for (int i = 0; i < values.get(0).length; i++) {

            // Convert arraylist to int[].
            Double[] result = temp.toArray(new Double[temp.size()]);
            double[] finalResult = new double[result.length]; // This hold final result.
            for (int i = 0; i < result.length; i++) {
                finalResult[i] = result[i].doubleValue();

            for (int i = 0; i < finalResult.length; i++) {

How to call javascript from a href?

another way is :

<a href="javascript:void(0);" onclick="alert('testing')">

Ansible - read inventory hosts and variables to group_vars/all file

Yes the example by nixlike works very well.


myhost1 user=barbara
myhost2 user=heather



- hosts: localhost
  connection: local         

        - name: loop debug inventory hostnames
            msg: "the docker host is {{ item }}"
          with_inventory_hostnames: docker-host
        - name: loop debug items
            msg: "the docker host is {{ hostvars[item]['user'] }}"
          with_items: "{{ groups['docker-host'] }}"


ansible-playbook ansible/tests/vars-test-local.yml

PLAY [localhost]

TASK [setup] ******************************************************************* ok: [localhost]

TASK [loop debug inventory hostnames] ****************************************** ok: [localhost] => (item=myhost2) => { "item": "myhost2", "msg": "the docker host is myhost2" } ok: [localhost] => (item=myhost1) => { "item": "myhost1", "msg": "the docker host is myhost1" }

TASK [loop debug items] ******************************************************** ok: [localhost] => (item=myhost1) => { "item": "myhost1", "msg": "the docker host is barbara" } ok: [localhost] => (item=myhost2) => { "item": "myhost2", "msg": "the docker host is heather" }

PLAY RECAP ********************************************************************* localhost : ok=3 changed=0 unreachable=0


What is the meaning of curly braces?

A dictionary is something like an array that's accessed by keys (e.g. strings,...) rather than just plain sequential numbers. It contains key/value pairs, you can look up values using a key like using a phone book: key=name, number=value.

For defining such a dictionary, you use this syntax using curly braces, see also:

When to use Hadoop, HBase, Hive and Pig?

I implemented a Hive Data platform recently in my firm and can speak to it in first person since I was a one man team.


  1. To have the daily web log files collected from 350+ servers daily queryable thru some SQL like language
  2. To replace daily aggregation data generated thru MySQL with Hive
  3. Build Custom reports thru queries in Hive

Architecture Options

I benchmarked the following options:

  1. Hive+HDFS
  2. Hive+HBase - queries were too slow so I dumped this option


  1. Daily log Files were transported to HDFS
  2. MR jobs parsed these log files and output files in HDFS
  3. Create Hive tables with partitions and locations pointing to HDFS locations
  4. Create Hive query scripts (call it HQL if you like as diff from SQL) that in turn ran MR jobs in the background and generated aggregation data
  5. Put all these steps into an Oozie workflow - scheduled with Daily Oozie Coordinator


HBase is like a Map. If you know the key, you can instantly get the value. But if you want to know how many integer keys in Hbase are between 1000000 and 2000000 that is not suitable for Hbase alone.

If you have data that needs to be aggregated, rolled up, analyzed across rows then consider Hive.

Hopefully this helps.

Hive actually rocks ...I know, I have lived it for 12 months now... So does HBase...

Sort a list alphabetically

There are two ways:

Without LINQ: yourList.Sort();

With LINQ: yourList.OrderBy(x => x).ToList()

You will find more information in:

How to insert 1000 rows at a time

You can use the following CTE as well. You can just modify it as you find fit. But this will add the same values into the student CTE.

This will add 1000 records but you can change it to 10000 or to a maximum of 32767

;WITH thetable(rowid,sname,semail,spassword) AS
    SELECT 1  , 'name' , 'email' , 'password'
    SELECT rowid+1 ,'name' , 'email' , 'password' 
    FROM thetable WHERE rowid < 1000

SELECT rowid,sname,semail,spassword 
FROM thetable ORDER BY rowid

Intel's HAXM equivalent for AMD on Windows OS

hello to run the avd manager on AMD processor you need update your SDK MANAGER in Android Studio:

You go to tools->SDK MANAGER->SDK Tools

then look for Android Emulator and Android Emulator Hypervisor Driver for AMD Processors

check the boxes and click apply or OK

Add timer to a Windows Forms application

Something like this in your form main. Double click the form in the visual editor to create the form load event.

 Timer Clock=new Timer();
 Clock.Interval=2700000; // not sure if this length of time will work 
 Clock.Tick+=new EventHandler(Timer_Tick);

Then add an event handler to do something when the timer fires.

  public void Timer_Tick(object sender,EventArgs eArgs)
      // do something here      

Loading basic HTML in Node.js

try this one:

var http = require('http');
var fs = require('fs');
var PORT = 8080;

http.createServer((req, res) => {
    fs.readFile('./' + req.url, (err, data) => {
        if (!err) {
            var dotoffset = req.url.lastIndexOf('.');
            var mimetype = dotoffset == -1 ? 'text/plaint' : {
                '.html': 'text/html',
                '.css': 'text/css',
                '.js': 'text/javascript',
                '.jpg': 'image/jpeg',
                '.png': 'image/png',
                '.ico': 'image/x-icon',
                '.gif': 'image/gif'
            }[ req.url.substr(dotoffset) ];
            res.setHeader('Content-Type', mimetype);
            console.log(req.url, mimetype);
        } else {
            console.log('File not fount: ' + req.url);
            res.writeHead(404, "Not Found");

With this, you can include js, css source-codes when linking them and you can load icons, imgs, gifs. And if you want, you can add more if you need.

Java :Add scroll into text area

Try adding these two lines to your code. I hope it will work. It worked for me :)


Picture of output is shown below

enter image description here

Best way to detect Mac OS X or Windows computers with JavaScript or jQuery

Is this what you are looking for? Otherwise, let me know and I will remove this post.

Try this jQuery plugin:


This is based on quirksmode BrowserDetect a wrap for jQuery browser/os detection plugin.

For keen readers:

And more code around the plugin resides here:

How to get Current Directory?

The question is not clear whether the current working directory is wanted or the path of the directory containing the executable.

Most answers seem to answer the latter.

But for the former, and for the second part of the question of creating the file, the C++17 standard now incorporates the filesystem library which simplifies this a lot:

#include <filesystem>
#include <iostream>

std::filesystem::path cwd = std::filesystem::current_path() / "filename.txt";
std::ofstream file(cwd.string());

This fetches the current working directory, adds the filename to the path and creates an empty file. Note that the path object takes care of os dependent path handling, so cwd.string() returns an os dependent path string. Neato.

How to export html table to excel or pdf in php

If all you want is a simple excel worksheet try this:

header('Content-type: application/excel');
$filename = 'filename.xls';
header('Content-Disposition: attachment; filename='.$filename);

$data = '<html xmlns:x="urn:schemas-microsoft-com:office:excel">
    <!--[if gte mso 9]>
                    <x:Name>Sheet 1</x:Name>

   <table><tr><td>Cell 1</td><td>Cell 2</td></tr></table>

echo $data;

The key here is the xml data. This will keep excel from complaining about the file.

How to read one single line of csv data in Python?

Just for reference, a for loop can be used after getting the first row to get the rest of the file:

with open('file.csv', newline='') as f:
    reader = csv.reader(f)
    row1 = next(reader)  # gets the first line
    for row in reader:
        print(row)       # prints rows 2 and onward

android pick images from gallery

For only pick from local add this :


And this working nice :

    val i = Intent(Intent.ACTION_GET_CONTENT,MediaStore.Images.Media.EXTERNAL_CONTENT_URI)
    i.type = "image/*"
    startActivityForResult(Intent.createChooser(i,"Select Photo"),pickImageRequestCode)

delete vs delete[] operators in C++

delete is used for one single pointer and delete[] is used for deleting an array through a pointer. This might help you to understand better.

Angular 5 Reactive Forms - Radio Button Group

IF you want to derive usg Boolean true False need to add "[]" around value

<form [formGroup]="form">
  <input type="radio" [value]=true formControlName="gender" >Male
  <input type="radio" [value]=false formControlName="gender">Female

How do you check if a selector matches something in jQuery?

I prefer the

    if (jQuery("#anyElement").is("*")){...}

Which basically checks if this elements is a kind of "*" (any element). Just a cleaner syntax and the "is" makes more sense inside an "if"

add item to dropdown list in html using javascript

For higher performance, I recommend this:

var select = document.getElementById("year");
var options = [];
var option = document.createElement('option');

//for (var i = 2011; i >= 1900; --i)
for (var i = 1900; i < 2012; ++i)
    //var data = '<option value="' + escapeHTML(i) +'">" + escapeHTML(i) + "</option>';
    option.text = option.value = i;

select.insertAdjacentHTML('beforeEnd', options.join('\n'));

This avoids a redraw after each appendChild, which speeds up the process considerably, especially for a larger number of options.

Optional for generating the string by hand:

function escapeHTML(str)
    var div = document.createElement('div');
    var text = document.createTextNode(str);
    return div.innerHTML;

However, I would not use these kind of methods at all.
It seems crude. You best do this with a documentFragment:

var docfrag = document.createDocumentFragment();

for (var i = 1900; i < 2012; ++i)
     docfrag.appendChild(new Option(i, i));

var select = document.getElementById("year");

What does "ulimit -s unlimited" do?

ulimit -s unlimited lets the stack grow unlimited.

This may prevent your program from crashing if you write programs by recursion, especially if your programs are not tail recursive (compilers can "optimize" those), and the depth of recursion is large.

getaddrinfo: nodename nor servname provided, or not known

If all of the above fails, try to convert to UNIX Line Endings, or do:

brew install dos2unix
sudo dos2unix -c mac /private/etc/hosts

Maybe the hosts encoding is wrong.

hope this helps

Where is the Java SDK folder in my computer? Ubuntu 12.04

$ whereis java

java: /usr/bin/java /usr/lib/java /usr/bin/X11/java /usr/share/java /usr/share/man/man1/java.1.gz

How to find available directory objects on Oracle 11g system?

The ALL_DIRECTORIES data dictionary view will have information about all the directories that you have access to. That includes the operating system path

SELECT owner, directory_name, directory_path
  FROM all_directories

Connect to external server by using phpMyAdmin

In the config file, change the "host" variable to point to the external server. The config file is called and it will be in the main phpMyAdmin folder. There should be a line like this:

$cfg['Servers'][$i]['host'] = 'localhost';

Just change localhost to your server's IP address.

Note: you may have to configure the external server to allow remote connections, but I've done this several times on shared hosting so it should be fine.

How to get position of a certain element in strings vector, to use it as an index in ints vector?

I am a beginner so here is a beginners answer. The if in the for loop gives i which can then be used however needed such as Numbers[i] in another vector. Most is fluff for examples sake, the for/if really says it all.

int main(){
vector<string>names{"Sara", "Harold", "Frank", "Taylor", "Sasha", "Seymore"};
string req_name;
cout<<"Enter search name: "<<'\n';
    for(int i=0; i<=names.size()-1; ++i) {
            cout<<"The index number for "<<req_name<<" is "<<i<<'\n';
            return 0;
        else if(names[i]!=req_name && i==names.size()-1) {
            cout<<"That name is not an element in this vector"<<'\n';
        } else {

Foreach value from POST from form

Use array-like fields:

<input name="name_for_the_items[]"/>

You can loop through the fields:

foreach($_POST['name_for_the_items'] as $item)
  //do something with $item

Make HTML5 video poster be same size as video itself

I came up with this idea and it works perfectly. Okay so basically we want to get rid of the videos first frame from the display and then resize the poster to the videos actual size. If we then set the dimensions we have completed one of these tasks. Then only one remains. So now, the only way I know to get rid of the first frame is to actually define a poster. However we are going to give the video a faked one, one that doesn't exist. This will result in a blank display with the background transparent. I.e. our parent div's background will be visible.

Simple to use, however it might not work with all web browsers if you want to resize the dimension of the background of the div to the dimension of the video since my code is using "background-size".


<div class="video_poster">
    <video poster="dasdsadsakaslmklda.jpg" controls>
        <source src="videos/myvideo.mp4" type="video/mp4">
        Your browser does not support the video tag.


    background-size:694px 390px;

Link to "pin it" on pinterest without generating a button

I Found some code for wordpress:

 <script type="text/javascript">

    function insert_pinterest($content) {
        global $post;
        $posturl = urlencode(get_permalink()); //Get the post URL
        $pinspan = '<span class="pinterest-button">';
     $pinurl = '';
     $pinend = '</span>';
        $pattern = '//i';
        $replacement = $pinspan.$pinurl.'$2.$3'.$pindescription.$pinfinish.''.$pinend;
        $content = preg_replace( $pattern, $replacement, $content );
        //Fix the link problem
        $newpattern = '/<span class="pinterest-button"><\/a><\/span><\/a>/i';
     $replacement = '';
     $content = preg_replace( $newpattern, $replacement, $content );
     return $content;
    add_filter( 'the_content', 'insert_pinterest' );


Then you put the following in your PHP:

<?php $pinterestimage = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'full' ); ?>
<a href="<?php echo urlencode(get_permalink($post->ID)); ?>&media=<?php echo $pinterestimage[0]; ?>&description=<?php the_title(); ?>">Pin It</a>

How to dynamically change the color of the selected menu item of a web page?

It would probably be easiest to implement this using JavaScript ... Here's a JQuery script to demo ... As the others mentioned ... we have a class named 'active' to indicate the active tab - NOT the pseudo-class ':active.' We could have just as easily named it anything though ... selected, current, etc., etc.

/* CSS */

#nav { width:480px;margin:1em auto;}

#nav ul {margin:1em auto; padding:0; font:1em "Arial Black",sans-serif; }

#nav ul li{display:inline;} 

#nav ul li a{text-decoration:none; margin:0; padding:.25em 25px; background:#666; color:#ffffff;} 

#nav ul li a:hover{background:#ff9900; color:#ffffff;} 

#nav ul li {background:#ff9900; color:#ffffff;} 

/* JQuery Example */

<script type="text/javascript">
$(function (){

    $('#nav ul li a').each(function(){
        var path = window.location.href;
        var current = path.substring(path.lastIndexOf('/')+1);
        var url = $(this).attr('href');

        if(url == current){


 /* HTML */

<div id="nav" >
        <li><a href='index.php?1'>One</a></li>
        <li><a href='index.php?2'>Two</a></li>
        <li><a href='index.php?3'>Three</a></li>
        <li><a href='index.php?4'>Four</a></li>

How to see if a directory exists or not in Perl?

Use -d (full list of file tests)

if (-d "cgi-bin") {
    # directory called cgi-bin exists
elsif (-e "cgi-bin") {
    # cgi-bin exists but is not a directory
else {
    # nothing called cgi-bin exists

As a note, -e doesn't distinguish between files and directories. To check if something exists and is a plain file, use -f.

X-Frame-Options Allow-From multiple domains

From RFC 7034:

Wildcards or lists to declare multiple domains in one ALLOW-FROM statement are not permitted


How do I set the X-Frame-Options: ALLOW-FROM to support more than a single domain?

You can't. As a workaround you can use different URLs for different partners. For each URL you can use it's own X-Frame-Options value. For example:

partner   iframe URL       ALLOW-FROM

For you can just use X-Frame-Options: deny.

BTW, for now Chrome (and all webkit-based browsers) does not support ALLOW-FROM statements at all.

Compiler error: "class, interface, or enum expected"

You forgot your class declaration:

public class MyClass {

Python constructors and __init__

coonstructors are called automatically when you create a new object, thereby "constructing" the object. The reason you can have more than one init is because names are just references in python, and you are allowed to change what each variable references whenever you want (hence dynamic typing)

def func(): #now func refers to an empty funcion
func=5      #now func refers to the number 5
def func():
    print "something"    #now func refers to a different function

in your class definition, it just keeps the later one

Vector erase iterator

res.erase(it) always returns the next valid iterator, if you erase the last element it will point to .end()

At the end of the loop ++it is always called, so you increment .end() which is not allowed.

Simply checking for .end() still leaves a bug though, as you always skip an element on every iteration (it gets 'incremented' by the return from .erase(), and then again by the loop)

You probably want something like:

 while (it != res.end()) {
        it = res.erase(it);    

to erase each element

(for completeness: I assume this is a simplified example, if you simply want every element gone without having to perform an operation on it (e.g. delete) you should simply call res.clear())

When you only conditionally erase elements, you probably want something like

for ( ; it != res.end(); ) {
  if (condition) {
    it = res.erase(it);
  } else {

Rotate a div using javascript

Can be pretty easily done assuming you're using jQuery and css3:


<div id="clicker">Click Here</div>
<div id="rotating"></div>


#clicker { 
    width: 100px; 
    height: 100px; 
    background-color: Green; 

#rotating { 
    width: 100px; 
    height: 100px; 
    background-color: Red; 
    margin-top: 50px; 
    -webkit-transition: all 0.3s ease-in-out;
    -moz-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;

.rotated { 


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

Am I trying to connect to a TLS-enabled daemon without TLS?

The underlining problem is simple – lack of permission to /var/run/docker.sock unix domain socket.

From Daemon socket option chapter of Docker Command Line reference for Docker 1.6.0:

By default, a unix domain socket (or IPC socket) is created at /var/run/docker.sock, requiring either root permission, or docker group membership.

Steps necessary to grant rights to users are nicely described in Docker installation instructions for Fedora:

Granting rights to users to use Docker

The docker command line tool contacts the docker daemon process via a socket file /var/run/docker.sock owned by root:root. Though it's recommended to use sudo for docker commands, if users wish to avoid it, an administrator can create a docker group, have it own /var/run/docker.sock, and add users to this group.

$ sudo groupadd docker
$ sudo chown root:docker /var/run/docker.sock
$ sudo usermod -a -G docker $USERNAME

Log out and log back in for above changes to take effect. Please note that Docker packages of some Linux distributions (Ubuntu) do already place /var/run/docker.sock in the docker group making the first two of above steps unnecessary.

In case of OS X and boot2docker the situation is different; the Docker daemon runs inside a VM so the DOCKER_HOST environment variable must be set to this VM so that the Docker client could find the Docker daemon. This is done by running $(boot2docker shellinit) in the shell.

How to return images in flask response?

You use something like

from flask import send_file

def get_image():
    if request.args.get('type') == '1':
       filename = 'ok.gif'
       filename = 'error.gif'
    return send_file(filename, mimetype='image/gif')

to send back ok.gif or error.gif, depending on the type query parameter. See the documentation for the send_file function and the request object for more information.

403 - Forbidden: Access is denied. You do not have permission to view this directory or page using the credentials that you supplied

I had the same problem. It turned out that I didn't specify a default page and I didn't have any page that is named after the default page convention (default.html, defult.aspx etc). As a result, ASP.NET doesn't allow the user to browse the directory (not a problem in Visual Studio built-in web server that allows you to view the directory) and shows the error message. To fix it, I added one default page in Web.Config and it worked.

            <add value="myDefault.aspx"/>

What are all the common ways to read a file in Ruby?

content = `cat file`

I think this method is the most "uncommon" one. Maybe it is kind of tricky, but it works if cat is installed.

How to remove white space characters from a string in SQL Server

Remove new line characters with SQL column data

Update a set  a.CityName=Rtrim(Ltrim(REPLACE(REPLACE(a.CityName,CHAR(10),' '),CHAR(13),' ')))
,a.postalZone=Rtrim(Ltrim(REPLACE(REPLACE(a.postalZone,CHAR(10),' '),CHAR(13),' ')))  
From tAddress a 
inner Join  tEmployees p  on a.AddressId =p.addressId 
Where p.MigratedID is not null and p.AddressId is not null AND
(REPLACE(REPLACE(a.postalZone,CHAR(10),'Y'),CHAR(13),'X') Like 'Y%' OR REPLACE(REPLACE(a.CityName,CHAR(10),'Y'),CHAR(13),'X') Like 'Y%')

What is the difference between Bower and npm?

This answer is an addition to the answer of Sindre Sorhus. The major difference between npm and Bower is the way they treat recursive dependencies. Note that they can be used together in a single project.

On the npm FAQ: ( link from 6 Sep 2015)

It is much harder to avoid dependency conflicts without nesting dependencies. This is fundamental to the way that npm works, and has proven to be an extremely successful approach.

On Bower homepage:

Bower is optimized for the front-end. Bower uses a flat dependency tree, requiring only one version for each package, reducing page load to a minimum.

In short, npm aims for stability. Bower aims for minimal resource load. If you draw out the dependency structure, you will see this:


project root
[node_modules] // default directory for dependencies
 -> dependency A
 -> dependency B
    -> dependency A

 -> dependency C
    -> dependency B
       -> dependency A 
    -> dependency D

As you can see it installs some dependencies recursively. Dependency A has three installed instances!


project root
[bower_components] // default directory for dependencies
 -> dependency A
 -> dependency B // needs A
 -> dependency C // needs B and D
 -> dependency D

Here you see that all unique dependencies are on the same level.

So, why bother using npm?

Maybe dependency B requires a different version of dependency A than dependency C. npm installs both versions of this dependency so it will work anyway, but Bower will give you a conflict because it does not like duplication (because loading the same resource on a webpage is very inefficient and costly, also it can give some serious errors). You will have to manually pick which version you want to install. This can have the effect that one of the dependencies will break, but that is something that you will need to fix anyway.

So, the common usage is Bower for the packages that you want to publish on your webpages (e.g. runtime, where you avoid duplication), and use npm for other stuff, like testing, building, optimizing, checking, etc. (e.g. development time, where duplication is of less concern).

Update for npm 3:

npm 3 still does things differently compared to Bower. It will install the dependencies globally, but only for the first version it encounters. The other versions are installed in the tree (the parent module, then node_modules).

  • [node_modules]
    • dep A v1.0
    • dep B v1.0
      • dep A v1.0 (uses root version)
    • dep C v1.0
      • dep A v2.0 (this version is different from the root version, so it will be an nested installation)

For more information, I suggest reading the docs of npm 3

How do you run a Python script as a service in Windows?

There are a couple alternatives for installing as a service virtually any Windows executable.

Method 1: Use instsrv and srvany from rktools.exe

For Windows Home Server or Windows Server 2003 (works with WinXP too), the Windows Server 2003 Resource Kit Tools comes with utilities that can be used in tandem for this, called instsrv.exe and srvany.exe. See this Microsoft KB article KB137890 for details on how to use these utils.

For Windows Home Server, there is a great user friendly wrapper for these utilities named aptly "Any Service Installer".

Method 2: Use ServiceInstaller for Windows NT

There is another alternative using ServiceInstaller for Windows NT (download-able here) with python instructions available. Contrary to the name, it works with both Windows 2000 and Windows XP as well. Here are some instructions for how to install a python script as a service.

Installing a Python script

Run ServiceInstaller to create a new service. (In this example, it is assumed that python is installed at c:\python25)

Service Name  : PythonTest
Display Name : PythonTest 
Startup : Manual (or whatever you like)
Dependencies : (Leave blank or fill to fit your needs)
Executable : c:\python25\python.exe
Arguments : c:\path_to_your_python_script\
Working Directory : c:\path_to_your_python_script

After installing, open the Control Panel's Services applet, select and start the PythonTest service.

After my initial answer, I noticed there were closely related Q&A already posted on SO. See also:

Can I run a Python script as a service (in Windows)? How?

How do I make Windows aware of a service I have written in Python?

How to apply shell command to each line of a command output?

for s in `cmd`; do echo $s; done

If cmd has a large output:

cmd | xargs -L1 echo

Changing the color of a clicked table row using jQuery

in your css:

    background: #F00;

in the jquery:

$("#data tr").click(function(){

Basically you create a class and adds/removes it from the selected row.

Btw you could have shown more effort, there's no css or jquery/js at all in your code xD

How do I create a view controller file after creating a new view controller?

Correct, when you drag a view controller object onto your storyboard in order to create a new scene, it doesn't automatically make the new class for you, too.

Having added a new view controller scene to your storyboard, you then have to:

  1. Create a UIViewController subclass. For example, go to your target's folder in the project navigator panel on the left and then control-click and choose "New File...". Choose a "Cocoa Touch Class":

    Cocoa Touch Class

    And then select a unique name for the new view controller subclass:

    UIViewController subclass

  2. Specify this new subclass as the base class for the scene you just added to the storyboard.

    enter image description here

  3. Now hook up any IBOutlet and IBAction references for this new scene with the new view controller subclass.

How to read a file without newlines?

You can read the whole file and split lines using str.splitlines:

temp =

Or you can strip the newline by hand:

temp = [line[:-1] for line in file]

Note: this last solution only works if the file ends with a newline, otherwise the last line will lose a character.

This assumption is true in most cases (especially for files created by text editors, which often do add an ending newline anyway).

If you want to avoid this you can add a newline at the end of file:

with open(the_file, 'r+') as f:, 2)  # go at the end of the file
    if != '\n':
        # add missing newline if not already present
    lines = [line[:-1] for line in f]

Or a simpler alternative is to strip the newline instead:

[line.rstrip('\n') for line in file]

Or even, although pretty unreadable:

[line[:-(line[-1] == '\n') or len(line)+1] for line in file]

Which exploits the fact that the return value of or isn't a boolean, but the object that was evaluated true or false.

The readlines method is actually equivalent to:

def readlines(self):
    lines = []
    for line in iter(self.readline, ''):
    return lines

# or equivalently

def readlines(self):
    lines = []
    while True:
        line = self.readline()
        if not line:
    return lines

Since readline() keeps the newline also readlines() keeps it.

Note: for symmetry to readlines() the writelines() method does not add ending newlines, so f2.writelines(f.readlines()) produces an exact copy of f in f2.

Java reflection: how to get field value from an object, not knowing its class

Assuming a simple case, where your field is public:

List list; // from your method
for(Object x : list) {
    Class<?> clazz = x.getClass();
    Field field = clazz.getField("fieldName"); //Note, this can throw an exception if the field doesn't exist.
    Object fieldValue = field.get(x);

But this is pretty ugly, and I left out all of the try-catches, and makes a number of assumptions (public field, reflection available, nice security manager).

If you can change your method to return a List<Foo>, this becomes very easy because the iterator then can give you type information:

List<Foo> list; //From your method
for(Foo foo:list) {
    Object fieldValue = foo.fieldName;

Or if you're consuming a Java 1.4 interface where generics aren't available, but you know the type of the objects that should be in the list...

List list;
for(Object x: list) {
   if( x instanceof Foo) {
      Object fieldValue = ((Foo)x).fieldName;

No reflection needed :)

static function in C

pmg's answer is very convincing. If you would like to know how static declarations work at object level then this below info could be interesting to you. I reused the same program written by pmg and compiler it into a .so(shared object) file

Following contents are after dumping the .so file into something human readable

0000000000000675 f1: address of f1 function

000000000000068c f2: address of f2(staticc) function

note the difference in the function address , it means something . For a function that's declared with different address , it can very well signify that f2 lives very far away or in a different segment of the object file.

Linkers use something called PLT(Procedure linkage table) and GOT(Global offsets table) to understand symbols that they have access to link to .

For now think that GOT and PLT magically bind all the addresses and a dynamic section holds information of all these functions that are visible by linker.

After dumping the dynamic section of the .so file we get a bunch of entries but only interested in f1 and f2 function.

The dynamic section holds entry only for f1 function at address 0000000000000675 and not for f2 !

Num: Value Size Type Bind Vis Ndx Name

 9: 0000000000000675    23 FUNC    GLOBAL DEFAULT   11 f1

And thats it !. From this its clear that the linker will be unsuccessful in finding the f2 function since its not in the dynamic section of the .so file.

add image to uitableview cell

Standard UITableViewCell already contains UIImageView that appears to the left to all your labels if its image is set. You can access it using imageView property:

cell.imageView.image = someImage;

If for some reason standard behavior does not suit your needs (note that you can customize properties of that standard image view) then you can add your own UIImageView to the cell as Aman suggested in his answer. But in that approach you'll have to manage cell's layout yourself (e.g. make sure that cell labels do not overlap image). And do not add subviews to the cell directly - add them to cell's contentView:

// DO NOT!
[cell addSubview:imv]; 
// DO:
[cell.contentView addSubview:imv];

Append to the end of a file in C

Following the documentation of fopen:

``a'' Open for writing. The file is created if it does not exist. The stream is positioned at the end of the file. Subsequent writes to the file will always end up at the then cur- rent end of file, irrespective of any intervening fseek(3) or similar.

So if you pFile2=fopen("myfile2.txt", "a"); the stream is positioned at the end to append automatically. just do:

FILE *pFile;
FILE *pFile2;
char buffer[256];

pFile=fopen("myfile.txt", "r");
pFile2=fopen("myfile2.txt", "a");
if(pFile==NULL) {
    perror("Error opening file.");
else {
    while(fgets(buffer, sizeof(buffer), pFile)) {
        fprintf(pFile2, "%s", buffer);

How to increase maximum execution time in php

You can try to set_time_limit(n). However, if your PHP setup is running in safe mode, you can only change it from the php.ini file.

Make XmlHttpRequest POST using JSON

If you use JSON properly, you can have nested object without any issue :

var xmlhttp = new XMLHttpRequest();   // new HttpRequest instance 
var theUrl = "/json-handler";"POST", theUrl);
xmlhttp.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
xmlhttp.send(JSON.stringify({ "email": "[email protected]", "response": { "name": "Tester" } }));

Group by multiple field names in java 8

Define a class for key definition in your group.

class KeyObj {

    ArrayList<Object> keys;

    public KeyObj( Object... objs ) {
        keys = new ArrayList<Object>();

        for (int i = 0; i < objs.length; i++) {
            keys.add( objs[i] );

    // Add appropriate isEqual() ... you IDE should generate this


Now in your code,

peopleByManyParams = people
            .collect(Collectors.groupingBy(p -> new KeyObj( p.age, p.other1, p.other2 ), Collectors.mapping((Person p) -> p, toList())));

open cv error: (-215) scn == 3 || scn == 4 in function cvtColor

i think it because cv2.imread cannot read .jpg picture, you need to change .jpg to .png.

Big O, how do you calculate/approximate it?

What often gets overlooked is the expected behavior of your algorithms. It doesn't change the Big-O of your algorithm, but it does relate to the statement "premature optimization. . .."

Expected behavior of your algorithm is -- very dumbed down -- how fast you can expect your algorithm to work on data you're most likely to see.

For instance, if you're searching for a value in a list, it's O(n), but if you know that most lists you see have your value up front, typical behavior of your algorithm is faster.

To really nail it down, you need to be able to describe the probability distribution of your "input space" (if you need to sort a list, how often is that list already going to be sorted? how often is it totally reversed? how often is it mostly sorted?) It's not always feasible that you know that, but sometimes you do.

How to add number of days in postgresql datetime

For me I had to put the whole interval in single quotes not just the value of the interval.

select id,  
   created_at + interval '1 day' * claim_window as deadline from projects   

Instead of

select id,  
   created_at + interval '1' day * claim_window as deadline from projects   

Postgres Date/Time Functions

Does adding a duplicate value to a HashSet/HashMap replace the previous value

Correct me if I'm wrong but what you're getting at is that with strings, "Hi" == "Hi" doesn't always come out true (because they're not necessarily the same object).

The reason you're getting an answer of 1 though is because the JVM will reuse strings objects where possible. In this case the JVM is reusing the string object, and thus overwriting the item in the Hashmap/Hashset.

But you aren't guaranteed this behavior (because it could be a different string object that has the same value "Hi"). The behavior you see is just because of the JVM's optimization.

Failed to load resource under Chrome

I was getting this error, only in Chrome (last version 24.0.1312.57 m), and only if the image was larger than the html img. I was using a php script to output the image like this:

header('Content-Length: '.strlen($data));
header("Content-type: image/{$ext}");
echo base64_decode($data);

I resolved it adding 1 to the lenght of the image:

header('Content-Length: '.strlen($data) + 1);
header("Content-type: image/{$ext}");
echo base64_decode($data);

Appears that Chrome dont expect the correct number of bytes.

Tested with sucess in Chrome and IE 9. Hope this help.

Push item to associative array in PHP

WebbieDave's solution will work. If you don't want to overwrite anything that might already be at 'name', you can also do something like this:

$options['inputs']['name'][] = $new_input['name'];

How to create and write to a txt file using VBA

Use FSO to create the file and write to it.

Dim fso as Object
Set fso = CreateObject("Scripting.FileSystemObject")
Dim oFile as Object
Set oFile = FSO.CreateTextFile(strPath)
oFile.WriteLine "test" 
Set fso = Nothing
Set oFile = Nothing    

See the documentation here:

BSTR to std::string (std::wstring) and vice versa

BSTR to std::wstring:

// given BSTR bs
assert(bs != nullptr);
std::wstring ws(bs, SysStringLen(bs));

std::wstring to BSTR:

// given std::wstring ws
BSTR bs = SysAllocStringLen(, ws.size());

Doc refs:

  1. std::basic_string<typename CharT>::basic_string(const CharT*, size_type)
  2. std::basic_string<>::empty() const
  3. std::basic_string<>::data() const
  4. std::basic_string<>::size() const
  5. SysStringLen()
  6. SysAllocStringLen()

Where in memory are my variables stored in C?

You got some of these right, but whoever wrote the questions tricked you on at least one question:

  • global variables -------> data (correct)
  • static variables -------> data (correct)
  • constant data types -----> code and/or data. Consider string literals for a situation when a constant itself would be stored in the data segment, and references to it would be embedded in the code
  • local variables(declared and defined in functions) --------> stack (correct)
  • variables declared and defined in main function -----> heap also stack (the teacher was trying to trick you)
  • pointers(ex: char *arr, int *arr) -------> heap data or stack, depending on the context. C lets you declare a global or a static pointer, in which case the pointer itself would end up in the data segment.
  • dynamically allocated space(using malloc, calloc, realloc) --------> stack heap

It is worth mentioning that "stack" is officially called "automatic storage class".

Comparing two input values in a form validation with AngularJS

You have to look at the bigger problem. How to write the directives that solve one problem. You should try directive use-form-error. Would it help to solve this problem, and many others.

    <form name="ExampleForm">
  <input ng-model="password" required />
   <label>Confirm password</label>
  <input ng-model="confirmPassword" required />
  <div use-form-error="isSame" use-error-expression="password && confirmPassword && password!=confirmPassword" ng-show="ExampleForm.$error.isSame">Passwords Do Not Match!</div>

Live example jsfiddle

What does "#include <iostream>" do?

That is a C++ standard library header file for input output streams. It includes functionality to read and write from streams. You only need to include it if you wish to use streams.

How do I rename both a Git local and remote branch name?

If you have named a branch incorrectly AND pushed this to the remote repository follow these steps to rename that branch (based on this article):

  1. Rename your local branch:

    • If you are on the branch you want to rename:
      git branch -m new-name

    • If you are on a different branch:
      git branch -m old-name new-name

  2. Delete the old-name remote branch and push the new-name local branch:
    git push origin :old-name new-name

  3. Reset the upstream branch for the new-name local branch:
    Switch to the branch and then:
    git push origin -u new-name

Copy Image from Remote Server Over HTTP

It's extremely simple using file_get_contents. Just provide the url as the first parameter.

Auto-increment primary key in SQL tables

Although the following is not way to do it in GUI but you can get autoincrementing simply using the IDENTITY datatype(start, increment):

CREATE TABLE "dbo"."TableName"
   name varchar(20),

the insert statement should list all columns except the id column (it will be filled with autoincremented value):

INSERT INTO "dbo"."TableName" (name) VALUES ('alpha');
INSERT INTO "dbo"."TableName" (name) VALUES ('beta');

and the result of

SELECT id, name FROM "dbo"."TableName";

will be

id    name
1     alpha
2     beta

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory

I lost some days with this problem.... until I found that in some file I was importing one static file, a built file. It make the build to never end. Something like:

import PropTypes from "../static/build/prop-types"; 

Fixing to the real source solved all the problem.

Sharing my solution. :)

Git list of staged files

You can Try using :- git ls-files -s

When should I create a destructor?

It's called a destructor/finalizer, and is usually created when implementing the Disposed pattern.

It's a fallback solution when the user of your class forgets to call Dispose, to make sure that (eventually) your resources gets released, but you do not have any guarantee as to when the destructor is called.

In this Stack Overflow question, the accepted answer correctly shows how to implement the dispose pattern. This is only needed if your class contain any unhandeled resources that the garbage collector does not manage to clean up itself.

A good practice is to not implement a finalizer without also giving the user of the class the possibility to manually Disposing the object to free the resources right away.

How to get JSON from webpage into Python script

There's no need to use an extra library to parse the json...

json.loads() returns a dictionary.

So in your case, just do text["someValueKey"]

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

you need to return when the readystate==4 e.g.

function httpGet(theUrl)
    if (window.XMLHttpRequest)
    {// code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
    {// code for IE6, IE5
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
        if (xmlhttp.readyState==4 && xmlhttp.status==200)
            return xmlhttp.responseText;
    }"GET", theUrl, false );

What is the maximum length of a Push Notification alert text?

Here're some screenshots (banner, alert, & notification center)

AlertBannerNotification Center

What is this property in Spring Boot?

The OSIV Anti-Pattern

Instead of letting the business layer decide how it’s best to fetch all the associations that are needed by the View layer, OSIV (Open Session in View) forces the Persistence Context to stay open so that the View layer can trigger the Proxy initialization, as illustrated by the following diagram.

enter image description here

  • The OpenSessionInViewFilter calls the openSession method of the underlying SessionFactory and obtains a new Session.
  • The Session is bound to the TransactionSynchronizationManager.
  • The OpenSessionInViewFilter calls the doFilter of the javax.servlet.FilterChain object reference and the request is further processed
  • The DispatcherServlet is called, and it routes the HTTP request to the underlying PostController.
  • The PostController calls the PostService to get a list of Post entities.
  • The PostService opens a new transaction, and the HibernateTransactionManager reuses the same Session that was opened by the OpenSessionInViewFilter.
  • The PostDAO fetches the list of Post entities without initializing any lazy association.
  • The PostService commits the underlying transaction, but the Session is not closed because it was opened externally.
  • The DispatcherServlet starts rendering the UI, which, in turn, navigates the lazy associations and triggers their initialization.
  • The OpenSessionInViewFilter can close the Session, and the underlying database connection is released as well.

At first glance, this might not look like a terrible thing to do, but, once you view it from a database perspective, a series of flaws start to become more obvious.

The service layer opens and closes a database transaction, but afterward, there is no explicit transaction going on. For this reason, every additional statement issued from the UI rendering phase is executed in auto-commit mode. Auto-commit puts pressure on the database server because each transaction issues a commit at end, which can trigger a transaction log flush to disk. One optimization would be to mark the Connection as read-only which would allow the database server to avoid writing to the transaction log.

There is no separation of concerns anymore because statements are generated both by the service layer and by the UI rendering process. Writing integration tests that assert the number of statements being generated requires going through all layers (web, service, DAO) while having the application deployed on a web container. Even when using an in-memory database (e.g. HSQLDB) and a lightweight webserver (e.g. Jetty), these integration tests are going to be slower to execute than if layers were separated and the back-end integration tests used the database, while the front-end integration tests were mocking the service layer altogether.

The UI layer is limited to navigating associations which can, in turn, trigger N+1 query problems. Although Hibernate offers @BatchSize for fetching associations in batches, and FetchMode.SUBSELECT to cope with this scenario, the annotations are affecting the default fetch plan, so they get applied to every business use case. For this reason, a data access layer query is much more suitable because it can be tailored to the current use case data fetch requirements.

Last but not least, the database connection is held throughout the UI rendering phase which increases connection lease time and limits the overall transaction throughput due to congestion on the database connection pool. The more the connection is held, the more other concurrent requests are going to wait to get a connection from the pool.

Spring Boot and OSIV

Unfortunately, OSIV (Open Session in View) is enabled by default in Spring Boot, and OSIV is really a bad idea from a performance and scalability perspective.

So, make sure that in the configuration file, you have the following entry:

This will disable OSIV so that you can handle the LazyInitializationException the right way.

Starting with version 2.0, Spring Boot issues a warning when OSIV is enabled by default, so you can discover this problem long before it affects a production system.

Detect WebBrowser complete page loading

The following should work.

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
    //Check if page is fully loaded or not
    if (this.webBrowser1.ReadyState != WebBrowserReadyState.Complete)
        //Action to be taken on page loading completion

Hidden features of Windows batch files

Search and replace when setting environment variables:

> @set fname=%date:/=%

...removes the "/" from a date for use in timestamped file names.

and substrings too...

> @set dayofweek=%fname:~0,3%

How to loop through a HashMap in JSP?

Depending on what you want to accomplish within the loop, iterate over one of these instead:

  • countries.keySet()
  • countries.entrySet()
  • countries.values()

Can I change the headers of the HTTP request sent by the browser?

ModHeader extension for Google Chrome, is also a good option. You can just set the Headers you want and just enter the URL in the browser, it will automatically take the headers from the extension when you hit the url. Only thing is, it will send headers for each and every URL you will hit so you have to disable or delete it after use.

SQLAlchemy: What's the difference between flush() and commit()?

A Session object is basically an ongoing transaction of changes to a database (update, insert, delete). These operations aren't persisted to the database until they are committed (if your program aborts for some reason in mid-session transaction, any uncommitted changes within are lost).

The session object registers transaction operations with session.add(), but doesn't yet communicate them to the database until session.flush() is called.

session.flush() communicates a series of operations to the database (insert, update, delete). The database maintains them as pending operations in a transaction. The changes aren't persisted permanently to disk, or visible to other transactions until the database receives a COMMIT for the current transaction (which is what session.commit() does).

session.commit() commits (persists) those changes to the database.

flush() is always called as part of a call to commit() (1).

When you use a Session object to query the database, the query will return results both from the database and from the flushed parts of the uncommitted transaction it holds. By default, Session objects autoflush their operations, but this can be disabled.

Hopefully this example will make this clearer:

s = Session()

s.add(Foo('A')) # The Foo('A') object has been added to the session.
                # It has not been committed to the database yet,
                #   but is returned as part of a query.
print 1, s.query(Foo).all()

s2 = Session()
s2.autoflush = False

print 2, s2.query(Foo).all() # The Foo('B') object is *not* returned
                             #   as part of this query because it hasn't
                             #   been flushed yet.
s2.flush()                   # Now, Foo('B') is in the same state as
                             #   Foo('A') was above.
print 3, s2.query(Foo).all() 
s2.rollback()                # Foo('B') has not been committed, and rolling
                             #   back the session's transaction removes it
                             #   from the session.
print 4, s2.query(Foo).all()

1 [<Foo('A')>]
2 [<Foo('A')>]
3 [<Foo('A')>, <Foo('B')>]
4 [<Foo('A')>]

CSS background-size: cover replacement for Mobile Safari

@media (max-width: @iphone-screen) {

How to check if a file exists in Ansible?

This can be achieved with the stat module to skip the task when file exists.

- hosts: servers
  - name: Ansible check file exists.
      path: /etc/issue
    register: p
  - debug:
      msg: "File exists..."
    when: p.stat.exists
  - debug:
      msg: "File not found"
    when: p.stat.exists == False

Easy way to turn JavaScript array into comma-separated list?

I liked the solution at because it adds spaces after commas:

array = ["test","test2","test3"]
array = array.toString();
array = array.replace(/,/g, ", ");

Or, as suggested by @StackOverflaw in the comments:

array.join(', ');

Explain why constructor inject is better than other options

With examples? Here's a simple one:

public class TwoInjectionStyles {
    private Foo foo;

    // Constructor injection
    public TwoInjectionStyles(Foo f) { = f;

    // Setting injection
    public void setFoo(Foo f) { = f; }

Personally, I prefer constructor injection when I can.

In both cases, the bean factory instantiates the TwoInjectionStyles and Foo instances and gives the former its Foo dependency.

How to get JSON from URL in JavaScript?

Axios is a promise based HTTP client for the browser and node.js.

It offers automatic transforms for JSON data and it's the official recommendation from the Vue.js team when migrating from the 1.0 version which included a REST client by default.

Performing a GET request

// Make a request for a user with a given ID
  .then(function (response) {
  .catch(function (error) {

Or even just axios(url) is enough as a GET request is the default.

fatal error: iostream.h no such file or directory

You should be using iostream without the .h.

Early implementations used the .h variants but the standard mandates the more modern style.

How to initialize const member variable in a class?

Another solution is

class T1
        t = 100


So t is initialised to 100 and it cannot be changed and it is private.

Display SQL query results in php

You cannot directly see the query result using mysql_query its only fires the query in mysql nothing else.

For getting the result you have to add a lil things in your script like

 $sql="SELECT * FROM  modul1open WHERE idM1O>=(SELECT FLOOR( MAX( idM1O ) * RAND( ) )  FROM  modul1open) ORDER BY idM1O LIMIT 1";

 $result = mysql_query($sql);
 //echo [$result];
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {

This will give you result;

How can I convert a string to upper- or lower-case with XSLT?

XSLT 2.0 has upper-case() and lower-case() functions. In case of XSLT 1.0, you can use translate():

<xsl:value-of select="translate("xslt", "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ")" />

Convert/cast an stdClass object to another class

I have a very similar problem. Simplified reflection solution worked just fine for me:

public static function cast($destination, \stdClass $source)
    $sourceReflection = new \ReflectionObject($source);
    $sourceProperties = $sourceReflection->getProperties();
    foreach ($sourceProperties as $sourceProperty) {
        $name = $sourceProperty->getName();
        $destination->{$name} = $source->$name;
    return $destination;

getElementById in React

import React, { useState } from 'react';

function App() {
  const [apes , setap] = useState('yo');
  const handleClick = () =>{
  return (
      <input id='name' />
      <h2> {apes} </h2>
      <button onClick={handleClick} />

export default App;

Trouble using ROW_NUMBER() OVER (PARTITION BY ...)

I would do something like this:

;WITH x 
                partition BY employeeid 
                ORDER BY datestart) rn 
     FROM   employeehistory) 
FROM   x x1 
                ON x1.rn = x2.rn + 1 

Or maybe it would be x2.rn - 1. You'll have to see. In any case, you get the idea. Once you have the table joined on itself, you can filter, group, sort, etc. to get what you need.

JAVA_HOME does not point to the JDK

The JAVA_HOME you have above only points to the JRE, which does not contain the compiler. Set your JAVA_HOME to


...and try again.

How can you check for a #hash in a URL using JavaScript?

Have you tried this?

if (url.indexOf('#') !== -1) {
    // Url contains a #

(Where url is the URL you want to check, obviously.)

How can I check if a string contains a character in C#?

You can use the extension method .Contains() from the namespace System.Linq:

using System.Linq;


    if (abc.ToLower().Contains('s')) { }

And no, to check if a boolean expression is true, you don't need == true

Since the Contains method is an extension method, my solution appeared to be confusing to some. Here are two versions that don't require you to add using System.Linq;:

if (abc.ToLower().IndexOf('s') != -1) { }

// or:

if (abc.IndexOf("s", StringComparison.CurrentCultureIgnoreCase) != -1) { }


If you want to, you can write your own extensions method for easier reuse:

public static class MyStringExtensions
    public static bool ContainsAnyCaseInvariant(this string haystack, char needle)
        return haystack.IndexOf(needle, StringComparison.InvariantCultureIgnoreCase) != -1;

    public static bool ContainsAnyCase(this string haystack, char needle)
        return haystack.IndexOf(needle, StringComparison.CurrentCultureIgnoreCase) != -1;

Then you can call them like this:

if (def.ContainsAnyCaseInvariant('s')) { }
// or
if (def.ContainsAnyCase('s')) { }

In most cases when dealing with user data, you actually want to use CurrentCultureIgnoreCase (or the ContainsAnyCase extension method), because that way you let the system handle upper/lowercase issues, which depend on the language. When dealing with computational issues, like names of HTML tags and so on, you want to use the invariant culture.

For example: In Turkish, the uppercase letter I in lowercase is i (without a dot), and not i (with a dot).

What's the difference between commit() and apply() in SharedPreferences

  • commit() is synchronously, apply() is asynchronous

  • apply() is void function.

  • commit() returns true if the new values were successfully written to persistent storage.

  • apply() guarantees complete before switching states , you don't need to worry about Android component lifecycles

If you dont use value returned from commit() and you're using commit() from main thread, use apply() instead of commit()

Regular Expressions: Is there an AND operator?

You could pipe your output to another regex. Using grep, you could do this:

grep A | grep B

Counting Number of Letters in a string variable

string yourWord = "Derp derp";

Console.WriteLine(new string(yourWord.Select(c => char.IsLetter(c) ? '_' : c).ToArray()));


____ ____

onSaveInstanceState () and onRestoreInstanceState ()

I think this thread was quite old. I just mention another case, that onSaveInstanceState() will also be called, is when you call Activity.moveTaskToBack(boolean nonRootActivity).

CSS selector based on element text?

It was probably discussed, but as of CSS3 there is nothing like what you need (see also "Is there a CSS selector for elements containing certain text?"). You will have to use additional markup, like this:

<li><span class="foo">some text</span></li>
<li>some other text</li>

Then refer to it the usual way:

li > {...}

How can I measure the similarity between two images?

Beyond Compare has pixel-by-pixel comparison for images, e.g.,

enter image description here

Rubymine: How to make Git ignore .idea files created by Rubymine

In the rubymine gui, there is an ignore list (settings/version control). Maybe try disabling it there. I got the hint from their support guys.

enter image description here

Raise to power in R

1: No difference. It is kept around to allow old S-code to continue to function. This is documented a "Note" in ?Math

2: Yes: But you already know it:

#[1] 1024

In R the mathematical operators are really functions that the parser takes care of rearranging arguments and function names for you to simulate ordinary mathematical infix notation. Also documented at ?Math.

Edit: Let me add that knowing how R handles infix operators (i.e. two argument functions) is very important in understanding the use of the foundational infix "[[" and "["-functions as (functional) second arguments to lapply and sapply:

> sapply( list( list(1,2,3), list(4,3,6) ), "[[", 1)
[1] 1 4
> firsts <- function(lis) sapply(lis, "[[", 1)
> firsts( list( list(1,2,3), list(4,3,6) ) )
[1] 1 4

Return number of rows affected by UPDATE statements

This is exactly what the OUTPUT clause in SQL Server 2005 onwards is excellent for.


CREATE TABLE [dbo].[test_table](
    [LockId] [int] IDENTITY(1,1) NOT NULL,
    [StartTime] [datetime] NULL,
    [EndTime] [datetime] NULL,
    [LockId] ASC

INSERT INTO test_table(StartTime, EndTime)
VALUES('2009 JUL 07','2009 JUL 07')
INSERT INTO test_table(StartTime, EndTime)
VALUES('2009 JUL 08','2009 JUL 08')
INSERT INTO test_table(StartTime, EndTime)
VALUES('2009 JUL 09','2009 JUL 09')
INSERT INTO test_table(StartTime, EndTime)
VALUES('2009 JUL 10','2009 JUL 10')
INSERT INTO test_table(StartTime, EndTime)
VALUES('2009 JUL 11','2009 JUL 11')
INSERT INTO test_table(StartTime, EndTime)
VALUES('2009 JUL 12','2009 JUL 12')
INSERT INTO test_table(StartTime, EndTime)
VALUES('2009 JUL 13','2009 JUL 13')

UPDATE test_table
    SET StartTime = '2011 JUL 01'
    OUTPUT INSERTED.* -- INSERTED reflect the value after the UPDATE, INSERT, or MERGE statement is completed 
    StartTime > '2009 JUL 09'

Results in the following being returned

    LockId StartTime                EndTime
4      2011-07-01 00:00:00.000  2009-07-10 00:00:00.000
5      2011-07-01 00:00:00.000  2009-07-11 00:00:00.000
6      2011-07-01 00:00:00.000  2009-07-12 00:00:00.000
7      2011-07-01 00:00:00.000  2009-07-13 00:00:00.000

In your particular case, since you cannot use aggregate functions with OUTPUT, you need to capture the output of INSERTED.* in a table variable or temporary table and count the records. For example,

  [LockId] [int],
  [StartTime] [datetime] NULL,
  [EndTime] [datetime] NULL 

UPDATE test_table
    SET StartTime = '2011 JUL 01'
    StartTime > '2009 JUL 09'

-- now get the count of affected records

TSQL How do you output PRINT in a user defined function?

I have tended in the past to work on my functions in two stages. The first stage would be to treat them as fairly normal SQL queries and make sure that I am getting the right results out of it. After I am confident that it is performing as desired, then I would convert it into a UDF.

Java: Convert String to TimeStamp

I should like to contribute the modern answer. When this question was asked in 2013, using the Timestamp class was right, for example for storing a date-time into your database. Today the class is long outdated. The modern Java date and time API came out with Java 8 in the spring of 2014, three and a half years ago. I recommend you use this instead.

Depending on your situation an exact requirements, there are two natural replacements for Timestamp:

  • Instant is a point on the time-line. For most purposes I would consider it safest to use this. An Instant is independent of time zone and will usually work well even in situations where your client device and your database server run different time zones.
  • LocalDateTime is a date and time of day without time zone, like 2011-10-02 18:48:05.123 (to quote the question).

A modern JDBC driver (JDBC 4.2 or higher) and other modern tools for database access will be happy to store either an Instant or a LocalDateTime into your database column of datatype timestamp. Both classes and the other date-time classes I am using in this answer belong to the modern API known as java.time or JSR-310.

It’s easiest to convert your string to LocalDateTime, so let’s take that first:

    DateTimeFormatter formatter
            = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss.SSS");
    String text = "2011-10-02 18:48:05.123";
    LocalDateTime dateTime = LocalDateTime.parse(text, formatter);

This prints


If your string was in yyyy-MM-dd format, instead do:

    String text = "2009-10-20";
    LocalDateTime dateTime = LocalDate.parse(text).atStartOfDay();

This prints


Or still better, take the output from LocalDate.parse() and store it into a database column of datatype date.

In both cases the procedure for converting from a LocalDateTime to an Instant is:

    Instant ts = dateTime.atZone(ZoneId.systemDefault()).toInstant();

I have specified a conversion using the JVM’s default time zone because this is what the outdated class would have used. This is fragile, though, since the time zone setting may be changed under our feet by other parts of your program or by other programs running in the same JVM. If you can, specify a time zone in the region/city format instead, for example:

    Instant ts = dateTime.atZone(ZoneId.of("Europe/Athens")).toInstant();

Using PHP variables inside HTML tags?

You can do it a number of ways, depending on the type of quotes you use:

  • echo "<a href='$param'>Click here</a>";
  • echo "<a href='{$param}'>Click here</a>";
  • echo '<a href="' . $param . '">Click here</a>';
  • echo "<a href=\"$param\">Click here</a>";

Double quotes allow for variables in the middle of the string, where as single quotes are string literals and, as such, interpret everything as a string of characters -- nothing more -- not even \n will be expanded to mean the new line character, it will just be the characters \ and n in sequence.

You need to be careful about your use of whichever type of quoting you decide. You can't use double quotes inside a double quoted string (as in your example) as you'll be ending the string early, which isn't what you want. You can escape the inner double quotes, however, by adding a backslash.

On a separate note, you might need to be careful about XSS attacks when printing unsafe variables (populated by the user) out to the browser.

Using set_facts and with_items together in Ansible

Updated 2018-06-08: My previous answer was a bit of hack so I have come back and looked at this again. This is a cleaner Jinja2 approach.

- name: Set fact 4
    foo: "{% for i in foo_result.results %}{% do foo.append(i) %}{% endfor %}{{ foo }}"

I am adding this answer as current best answer for Ansible 2.2+ does not completely cover the original question. Thanks to Russ Huguley for your answer this got me headed in the right direction but it left me with a concatenated string not a list. This solution gets a list but becomes even more hacky. I hope this gets resolved in a cleaner manner.

- name: build foo_string
    foo_string: "{% for i in foo_result.results %}{{ i.ansible_facts.foo_item }}{% if not loop.last %},{% endif %}{%endfor%}"

- name: set fact foo
    foo: "{{ foo_string.split(',') }}"

How to set lifetime of session

Sessions can be configured in your php.ini file or in your .htaccess file. Have a look at the PHP session documentation.

What you basically want to do is look for the line session.cookie_lifetime in php.ini and make it's value is 0 so that the session cookie is valid until the browser is closed. If you can't edit that file, you could add php_value session.cookie_lifetime 0 to your .htaccess file.

How merge two objects array in angularjs?

$ is not a function 

same problem with me but i solve the problem by

 $ = [].concat($ , data)

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

How to schedule a task to run when shutting down windows

For those who prefer using the Task Scheduler, it's possible to schedule a task to run after a restart / shutdown has been initiated by setting the task to run after event 1074 in the System log in the Event Viewer has been logged. However, it's only good for very short task, which will run as long as the system is restarting / shutting down, which is usually only a few seconds.

  • From the Task Scheduler:

    Begin the task: On an event
    Log: System
    Source: USER32
    EventID: 1074

  • From the command prompt:

    schtasks /create /tn "taskname" /tr "task file" /sc onevent /ec system /mo *[system/eventid=1074]

Comment: the /ec option is available from Windows Vista and above. (thank you @t2d)

Please note that the task status can be:

The operation being requested was not performed because the user has not logged on to the network. The specified service does not exist. (0x800704DD)

However, it doesn't mean that it didn't run.

Get connection string from App.config

string str = Properties.Settings.Default.myConnectionString; 

Angular.js: set element height on page load

$(document).ready(function() {
       scope.$apply(function() {

This also ensures that all the scripts have been loaded before the execution of the statements. If you dont need that you can use

$(window).load(function() {
       scope.$apply(function() {

How to use css style in php

css :hover kinda is like js onmouseover

row1 {
    // your css
row1:hover {
    color: red;
row1:hover #a, .b, .c:nth-child[3] {
    border: 1px solid red;

not too sure how it works but css applies styles to echo'ed ids

Visual Studio Code cannot detect installed git

First check if Git* installed or not in your system

by typing the command in cmd /command prompt (In windows)

where git

if you get an output like this

? where git

Then Go to Settings > Preferences > Settings and put the bellow code** right part.

    // If git enabled ?
    "git.enabled": true,

    // Path to the git executable
    "git.path": "C:\\cmder\\vendor\\git-for-windows\\cmd\\git.exe"

** Just add double slash (\\) just like the above code.


See (search the page for "BEGIN RSA PRIVATE KEY") (archive link for posterity, just in case).

BEGIN RSA PRIVATE KEY is PKCS#1 and is just an RSA key. It is essentially just the key object from PKCS#8, but without the version or algorithm identifier in front. BEGIN PRIVATE KEY is PKCS#8 and indicates that the key type is included in the key data itself. From the link:

The unencrypted PKCS#8 encoded data starts and ends with the tags:


Within the base64 encoded data the following DER structure is present:

PrivateKeyInfo ::= SEQUENCE {
  version         Version,
  algorithm       AlgorithmIdentifier,
  PrivateKey      BIT STRING

AlgorithmIdentifier ::= SEQUENCE {
  algorithm       OBJECT IDENTIFIER,
  parameters      ANY DEFINED BY algorithm OPTIONAL

So for an RSA private key, the OID is 1.2.840.113549.1.1.1 and there is a RSAPrivateKey as the PrivateKey key data bitstring.

As opposed to BEGIN RSA PRIVATE KEY, which always specifies an RSA key and therefore doesn't include a key type OID. BEGIN RSA PRIVATE KEY is PKCS#1:

RSA Private Key file (PKCS#1)

The RSA private key PEM file is specific for RSA keys.

It starts and ends with the tags:


Within the base64 encoded data the following DER structure is present:

RSAPrivateKey ::= SEQUENCE {
  version           Version,
  modulus           INTEGER,  -- n
  publicExponent    INTEGER,  -- e
  privateExponent   INTEGER,  -- d
  prime1            INTEGER,  -- p
  prime2            INTEGER,  -- q
  exponent1         INTEGER,  -- d mod (p-1)
  exponent2         INTEGER,  -- d mod (q-1)
  coefficient       INTEGER,  -- (inverse of q) mod p
  otherPrimeInfos   OtherPrimeInfos OPTIONAL

Listing all the folders subfolders and files in a directory using php

I'm really fond of SPL Library, they offer iterator's, including RecursiveDirectoryIterator.

Set transparent background using ImageMagick and commandline prompt

I had the same problem. In which i have to remove white background from jpg/png image format using ImageMagick.

What worked for me was:

1) Convert image format to png: convert input.jpg input.png

2) convert input.png -fuzz 2% -transparent white output.png

SQL Server 2005 Using CHARINDEX() To split a string

I wouldn't exactly say it is easy or obvious, but with just two hyphens, you can reverse the string and it is not too hard:

with t as (select 'LD-23DSP-1430' as val)
select t.*,
       LEFT(val, charindex('-', val) - 1),
   SUBSTRING(val, charindex('-', val)+1, len(val) - CHARINDEX('-', reverse(val)) - charindex('-', val)),
       REVERSE(LEFT(reverse(val), charindex('-', reverse(val)) - 1))
from t;

Beyond that and you might want to use split() instead.

How can I get the count of milliseconds since midnight for the current?

I did the test using java 8 It wont matter the order the builder always takes 0 milliseconds and the concat between 26 and 33 milliseconds under and iteration of a 1000 concatenation

Hope it helps try it with your ide

public void count() {

        String result = "";

        StringBuilder builder = new StringBuilder();

        long millis1 = System.currentTimeMillis(),

        for (int i = 0; i < 1000; i++) {
            builder.append("hello world this is the concat vs builder test enjoy");

        millis2 = System.currentTimeMillis();

        System.out.println("Diff: " + (millis2 - millis1));

        millis1 = System.currentTimeMillis();

        for (int i = 0; i < 1000; i++) {
            result += "hello world this is the concat vs builder test enjoy";

        millis2 = System.currentTimeMillis();

        System.out.println("Diff: " + (millis2 - millis1));

How to read a single character from the user?

if you just want to hold the screen so you can see the result on the terminal just write


at the end of the code and it will hold the screen

Using css transform property in jQuery

I started using the 'prefix-free' Script available at so I don't have to take care about the vendor prefixes. It neatly takes care of setting the correct vendor prefix behind the scenes for you. Plus a jQuery Plugin is available as well so one can still use jQuery's .css() method without code changes, so the suggested line in combination with prefix-free would be all you need:

$('.user-text').css('transform', 'scale(' + ui.value + ')');

Using NSPredicate to filter an NSArray based on NSDictionary keys

#import <Foundation/Foundation.h>
// clang -framework Foundation Siegfried.m 
main() {
    NSArray *arr = @[
        @{@"1" : @"Fafner"},
        @{@"1" : @"Fasolt"}
    NSPredicate *p = [NSPredicate predicateWithFormat:
        @"SELF['1'] CONTAINS 'e'"];
    NSArray *res = [arr filteredArrayUsingPredicate:p];
    NSLog(@"Siegfried %@", res);
    return 0;

Cannot find Microsoft.Office.Interop Visual Studio

If you're using Visual Studio 2015 and you're encountering this problem, you can install MS Office Developer Tools for VS2015 here.

How to add Class in <li> using wp_nav_menu() in Wordpress?

No need to create custom walker. Just use additional argument and set filter for nav_menu_css_class.

For example:

$args = array(
    'container'     => '',
    'theme_location'=> 'your-theme-loc',
    'depth'         => 1,
    'fallback_cb'   => false,
    'add_li_class'  => 'your-class-name1 your-class-name-2'

Notice the new 'add_li_class' argument.

And set the filter on functions.php

function add_additional_class_on_li($classes, $item, $args) {
    if(isset($args->add_li_class)) {
        $classes[] = $args->add_li_class;
    return $classes;
add_filter('nav_menu_css_class', 'add_additional_class_on_li', 1, 3);

How do I capture the output of a script if it is being ran by the task scheduler?

You can write to a log file on the lines that you want to output like this:

@echo off
echo Debugging started >C:\logfile.txt
echo More stuff
echo Debugging stuff >>C:\logfile.txt
echo Hope this helps! >>C:\logfile.txt

This way you can choose which commands to output if you don't want to trawl through everything, just get what you need to see. The > will output it to the file specified (creating the file if it doesn't exist and overwriting it if it does). The >> will append to the file specified (creating the file if it doesn't exist but appending to the contents if it does).

How can I save an image with PIL?

Try removing the . before the .bmp (it isn't matching BMP as expected). As you can see from the error, the save_handler is upper-casing the format you provided and then looking for a match in SAVE. However the corresponding key in that object is BMP (instead of .BMP).

I don't know a great deal about PIL, but from some quick searching around it seems that it is a problem with the mode of the image. Changing the definition of j to:

j = Image.fromarray(b, mode='RGB')

Seemed to work for me (however note that I have very little knowledge of PIL, so I would suggest using @mmgp's solution as s/he clearly knows what they are doing :) ). For the types of mode, I used this page - hopefully one of the choices there will work for you.

No provider for Http StaticInjectorError

I am on an angular project that (unfortunately) uses source code inclusion via tsconfig.json to connect different collections of code. I came across a similar StaticInjector error for a service (e.g.RestService in the top example) and I was able to fix it by listing the service dependencies in the deps array when providing the affected service in the module, for example:

import { HttpClient } from '@angular/common/http';
import { NgModule } from '@angular/core';
import { HttpModule } from '@angular/http';
import { RestService } from 'mylib/src/rest/rest.service';
  imports: [
  providers: [
      provide: RestService,
      useClass: RestService,
      deps: [HttpClient] /* the injected services in the constructor for RestService */

How to display a Yes/No dialog box on Android?

Thanks nikki your answer has helped me improve an existing simply by adding my desired action as follows

AlertDialog.Builder builder = new AlertDialog.Builder(this);

builder.setTitle("Do this action");
builder.setMessage("do you want confirm this action?");

builder.setPositiveButton("YES", new DialogInterface.OnClickListener() {

    public void onClick(DialogInterface dialog, int which) {
        // Do do my action here



builder.setNegativeButton("NO", new DialogInterface.OnClickListener() {

    public void onClick(DialogInterface dialog, int which) {
        // I do not need any action here you might

AlertDialog alert = builder.create();;

How to convert a Java String to an ASCII byte array?

Using the getBytes method, giving it the appropriate Charset (or Charset name).


String s = "Hello, there.";
byte[] b = s.getBytes(StandardCharsets.US_ASCII);

(Before Java 7: byte[] b = s.getBytes("US-ASCII");)

How to start debug mode from command prompt for apache tomcat server?

If you're wanting to do this via powershell on windows this worked for me



/path/to/tomcat/bin/catalina.bat jpda start