Programs & Examples On #Umbraco blog

Table overflowing outside of div

I tried almost all of above but did not work for me ... The following did

word-break: break-all;

This to be added on the parent div (container of the table .)

Print Html template in Angular 2 (ng-print in Angular 2)

I ran into the same issue and found another way to do this. It worked for in my case as it was a relatively small application.

First, the user will a click button in the component which needs to be printed. This will set a flag that can be accessed by the app component. Like so

.html file

<button mat-button (click)="printMode()">Print Preview</button>

.ts file

  printMode() {
    this.utilities.printMode = true;

In the html of the app component, we hide everything except the router-outlet. Something like below

<div class="container">       
  <app-header *ngIf="!utilities.printMode"></app-header>
    <mat-sidenav *ngIf="=!utilities.printMode">

With similar ngIf conidtions, we can also adjust the html template of the component to only show or hide things in printMode. So that the user will see only what needs to get printed when print preview is clicked.

We can now simply print or go back to normal mode with the below code

.html file

<button mat-button class="doNotPrint" (click)="print()">Print</button>
<button mat-button class="doNotPrint" (click)="endPrint()">Close</button>

.ts file

  print() {

  endPrint() {
    this.utilities.printMode = false;

.css file (so that the print and close button's don't get printed)

@media print{
   .doNotPrint{display:none !important;}

A long bigger than Long.MAX_VALUE

Firstly, the below method doesn't compile as it is missing the return type and it should be Long.MAX_VALUE in place of Long.Max_value.

public static boolean isBiggerThanMaxLong(long value) {
      return value > Long.Max_value;

The above method can never return true as you are comparing a long value with Long.MAX_VALUE , see the method signature you can pass only long there.Any long can be as big as the Long.MAX_VALUE, it can't be bigger than that.

You can try something like this with BigInteger class :

public static boolean isBiggerThanMaxLong(BigInteger l){
    return l.compareTo(BigInteger.valueOf(Long.MAX_VALUE))==1?true:false;

The below code will return true :

BigInteger big3 = BigInteger.valueOf(Long.MAX_VALUE).
System.out.println(isBiggerThanMaxLong(big3)); // prints true

Effect of using sys.path.insert(0, path) and sys.path(append) when loading modules

I'm quite a beginner in Python and I found the answer of Anand was very good but quite complicated to me, so I try to reformulate :

1) insert and append methods are not specific to sys.path and as in other languages they add an item into a list or array and :
* append(item) add item to the end of the list,
* insert(n, item) inserts the item at the nth position in the list (0 at the beginning, 1 after the first element, etc ...).

2) As Anand said, python search the import files in each directory of the path in the order of the path, so :
* If you have no file name collisions, the order of the path has no impact,
* If you look after a function already defined in the path and you use append to add your path, you will not get your function but the predefined one.

But I think that it is better to use append and not insert to not overload the standard behaviour of Python, and use non-ambiguous names for your files and methods.

python tuple to dict

Here are couple ways of doing it:

>>> t = ((1, 'a'), (2, 'b'))

>>> # using reversed function
>>> dict(reversed(i) for i in t)
{'a': 1, 'b': 2}

>>> # using slice operator
>>> dict(i[::-1] for i in t)
{'a': 1, 'b': 2}

How can I execute Python scripts using Anaconda's version of Python?

I like to run a "bare-bones" version of Python 2 to verify scripts that I create for other people without an advanced python setup. But Anaconda and Python 3 have a lot of nice features. To enjoy both things on the same computer I do this on my Windows computer which allows me to easily switch.

C:\Users>python --version
Python 2.7.11

C:\Users>conda create --name p3 python=3

C:\Users>conda info --envs
Using Anaconda Cloud api site
# conda environments:
p3                       C:\Anaconda3\envs\p3
root                  *  C:\Anaconda3

C:\Users>activate p3
Deactivating environment "C:\Anaconda3"...
Activating environment "C:\Anaconda3\envs\p3"...

[p3] C:\Users>python --version
Python 3.5.1 :: Continuum Analytics, Inc.

For more info:

How to make a query with group_concat in sql server

Please run the below query, it doesn't requires STUFF and GROUP BY in your case:

    , A.maskname
    , A.schoolid
    , B.schoolname
    , CAST((
          SELECT  T.maskdetail+','
          FROM dbo.maskdetails T
          WHERE A.maskid = T.maskid
          FOR XML PATH(''))as varchar(max)) as maskdetail 
FROM dbo.tblmask A
JOIN B ON B.ID = A.schoolid

How does java do modulus calculations with negative numbers?

Modulo arithmetic with negative operands is defined by the language designer, who might leave it to the language implementation, who might defer the definition to the CPU architecture.

I wasn't able to find a Java language definition.
Thanks Ishtar, Java Language Specification for the Remainder Operator % says that the sign of the result is the same as the sign of the numerator.

Transitions on the CSS display property

I think SalmanPK has the closest answer. It does fade an item in or out, with the following CSS animations. However, the display property does not animate smoothly, only the opacity.

@-webkit-keyframes fadeIn {
    from { opacity: 0; }
      to { opacity: 1; }

@-webkit-keyframes fadeOut {
    from { opacity: 1; }
      to { opacity: 0; }

If you want to animate the element moving from display block to display none, I can't see that it is currently possible just with CSS. You have to get the height and use a CSS animation to decrease the height. This is possible with CSS as shown in the example below, but it would be tricky to know the exact height values you need to animate for an element.

jsFiddle example


@-webkit-keyframes pushDown {
  0% {
    height: 10em;
  25% {
    height: 7.5em;
  50% {
    height: 5em;
  75% {
    height: 2.5em;
  100% {
    height: 0em;

.push-down {
    -webkit-animation: pushDown 2s forwards linear;


var element = document.getElementById("element");

// Push item down
element.className = element.className + " push-down";

OpenCV with Network Cameras

I enclosed C++ code for grabbing frames. It requires OpenCV version 2.0 or higher. The code uses cv::mat structure which is preferred to old IplImage structure.

#include "cv.h"
#include "highgui.h"
#include <iostream>

int main(int, char**) {
    cv::VideoCapture vcap;
    cv::Mat image;

    const std::string videoStreamAddress = "rtsp://cam_address:554/live.sdp"; 
    /* it may be an address of an mjpeg stream, 
    e.g. "http://user:pass@cam_address:8081/cgi/mjpg/mjpg.cgi?.mjpg" */

    //open the video stream and make sure it's opened
    if(! {
        std::cout << "Error opening video stream or file" << std::endl;
        return -1;

    //Create output window for displaying frames. 
    //It's important to create this window outside of the `for` loop
    //Otherwise this window will be created automatically each time you call
    //`imshow(...)`, which is very inefficient. 
    cv::namedWindow("Output Window");

    for(;;) {
        if(! {
            std::cout << "No frame" << std::endl;
        cv::imshow("Output Window", image);
        if(cv::waitKey(1) >= 0) break;

Update You can grab frames from H.264 RTSP streams. Look up your camera API for details to get the URL command. For example, for an Axis network camera the URL address might be:

// H.264 stream RTSP address, where is an IP address 
// and 554 is the port number

// if the camera is password protected
rtsp://username:[email protected]:554/axis-media/media.amp

Set opacity of background image without affecting child elements

You can put the image in the div:after or div:before and set the opacity on that "virtual div"

div:after {
  background: url(;
  opacity: 0.25;

found here

Click event on select option element in chrome

Maybe one of the new jquery versions supports the click event on options. It worked for me:

$(document).on("click","select option",function() {
  console.log("nice to meet you, console ;-)");

UPDATE: A possible usecase could be the following: A user sends a html form and the values are inserted into a database. However one or more values are set by default and you flag this automated entries. You also show the user that his entry is generated automatically, but if he confirm the entry by clicking on the already selected option you change the flag in the database. A rare sue case, but possible...

How to form a correct MySQL connection string?

try creating connection string this way:

MySqlConnectionStringBuilder conn_string = new MySqlConnectionStringBuilder();
conn_string.Server = "";
conn_string.UserID = "a455555_test";
conn_string.Password = "a455555_me";
conn_string.Database = "xxxxxxxx";

using (MySqlConnection conn = new MySqlConnection(conn_string.ToString()))
using (MySqlCommand cmd = conn.CreateCommand())
{    //watch out for this SQL injection vulnerability below
     cmd.CommandText = string.Format("INSERT Test (lat, long) VALUES ({0},{1})",
                                    OSGconv.deciLat, OSGconv.deciLon);

Which "href" value should I use for JavaScript links, "#" or "javascript:void(0)"?

It would be better to use jQuery,

$(document).ready(function() {
    $("a").css("cursor", "pointer");

and omit both href="#" and href="javascript:void(0)".

The anchor tag markup will be like

<a onclick="hello()">Hello</a>

Simple enough!

Angular2: child component access parent class variable/function

The main article in the Angular2 documentation on this subject is :!#parent-to-child

It covers the following:

  • Pass data from parent to child with input binding

  • Intercept input property changes with a setter

  • Intercept input property changes with ngOnChanges

  • Parent listens for child event

  • Parent interacts with child via a local variable

  • Parent calls a ViewChild

  • Parent and children communicate via a service

Generating random, unique values C#

You might try shuffling an array of possible ints if your range is only 0 through 9. This adds the benefit of avoiding any conflicts in the number generation.

var nums = Enumerable.Range(0, 10).ToArray();
var rnd = new Random();

// Shuffle the array
for (int i = 0;i < nums.Length;++i)
    int randomIndex = rnd.Next(nums.Length);
    int temp = nums[randomIndex];
    nums[randomIndex] = nums[i];
    nums[i] = temp;

// Now your array is randomized and you can simply print them in order
for (int i = 0;i < nums.Length;++i)

Two onClick actions one button

Try it:

<input type="button" value="Dont show this again! " onClick="fbLikeDump();WriteCookie();" />

Or also

function clickEvent(){
<input type="button" value="Dont show this again! " onClick="clickEvent();" />

How to find Port number of IP address?

DNS server usually have a standard of ports used. But if it's different, you could try nmap and do a port scan like so:

> nmap

Can I use library that used android support with Androidx projects.

I had a problem like this before, it was the file doesn't exist, only the , so i went to my project folder and i copied & pasted the file but without .txt extension then it finally worked.

How can I increment a date by one day in Java?

You can use this package from "org.apache.commons.lang3.time":

 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
 Date myNewDate = DateUtils.addDays(myDate, 4);
 Date yesterday = DateUtils.addDays(myDate, -1);
 String formatedDate = sdf.format(myNewDate);  

Classes vs. Modules in VB.NET

I think it's a good idea to keep avoiding modules unless you stick them into separate namespaces. Because in Intellisense methods in modules will be visible from everywhere in that namespace.

So instead of ModuleName.MyMethod() you end up with MyMethod() popups in anywhere and this kind of invalidates the encapsulation. (at least in the programming level).

That's why I always try to create Class with shared methods, seems so much better.

Must issue a STARTTLS command first

    String username = "[email protected]";
    String password = "some-password";
    String recipient = "[email protected]");

    Properties props = new Properties();

    props.put("", "");
    props.put("mail.from", "[email protected]");
    props.put("mail.smtp.starttls.enable", "true");
    props.put("mail.smtp.port", "587");
    props.setProperty("mail.debug", "true");

    Session session = Session.getInstance(props, null);
    MimeMessage msg = new MimeMessage(session);

    msg.setRecipients(Message.RecipientType.TO, recipient);
    msg.setSubject("JavaMail hello world example");
    msg.setSentDate(new Date());
    msg.setText("Hello, world!\n");

    Transport transport = session.getTransport("smtp");

    transport.connect(username, password);
    transport.sendMessage(msg, msg.getAllRecipients());

How to view Plugin Manager in Notepad++

A direct process to install / configure Plugin Manager :

  1. Download the latest version of NotepadPlus Plugin Manager from the official Github handle.
  2. Extract the zip file.
  3. Copy the pluginmanager.dll file and paste in C:\Program Files\Notepad++\Plugins\PluginManager directory.
  4. Restart the Notepad++

Note: Create the PluginManager directory if it is not present.

Array String Declaration

You are not initializing your String[]. You either need to initialize it using the exact array size, as suggested by @Tr?nSiLong, or use a List<String> and then convert to a String[] (in case you do not know the length):

String[] title = {
        "Drug Addiction"
String urlbase = "";
String imgSel = "/logo.png";
List<String> mStrings = new ArrayList<String>();

for(int i=0;i<title.length;i++) {
    mStrings.add(urlbase + title[i].toLowerCase() + imgSel);


String[] strings = new String[mStrings.size()];
strings = mStrings.toArray(strings);//now strings is the resulting array

Prevent textbox autofill with previously entered values

Autocomplete need to set off from textbox

<asp:TextBox ID="TextBox1" runat="server" autocomplete="off"></asp:TextBox>

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 32 bytes)

128M == 134217728, the number you are seeing.

The memory limit is working fine. When it says it tried to allocate 32 bytes, that the amount requested by the last operation before failing.

Are you building any huge arrays or reading large text files? If so, remember to free any memory you don't need anymore, or break the task down into smaller steps.

Laravel 5.4 redirection to custom url after login

Path Customization (tested in laravel 7) When a user is successfully authenticated, they will be redirected to the /home URI. You can customize the post-authentication redirect path using the HOME constant defined in your RouteServiceProvider:

public const HOME = '/home';

How to prevent sticky hover effects for buttons on touch devices

This works perfectly in 2 steps.

  1. Set your body tag to be like this <body ontouchstart="">. I'm not a fan of this "hack", but it allows Safari on iOS to react to touches instantly. Not sure how, but it works.

  2. Set up your touchable class like this:

    // I did this in SASS, but this should work with normal CSS as well
    // Touchable class
    .example {
        // Default styles
        background: green;
        // Default hover styles 
        // (Think of this as Desktop and larger)
        &:hover {
            background: yellow;
        // Default active styles
        &:active {
            background: red;
        // Setup breakpoint for smaller device widths
        @media only screen and (max-width: 1048px) {
            // Important!
            // Reset touchable hover styles
            // You may want to use the same exact styles as the Default styles
            &:hover {
                background: green;
            // Important!
            // Touchable active styles
            &:active {
                background: red;

You may want to remove any animation on your touchable class as well. Android Chrome seems to be a little slower than iOS.

This will also result in the active state being applied if the user scrolls the page while touching your class.

Replace "\\" with "\" in a string in C#

You can simply do a replace in your string like


successful/fail message pop up box after submit?

You are echoing outside the body tag of your HTML. Put your echos there, and you should be fine.

Also, remove the onclick="alert()" from your submit. This is the cause for your first undefined message.

  $posted = false;
  if( $_POST ) {
    $posted = true;

    // Database stuff here...
    // $result = mysql_query( ... )
    $result = $_POST['name'] == "danny"; // Dummy result


    if( $posted ) {
      if( $result ) 
        echo "<script type='text/javascript'>alert('submitted successfully!')</script>";
        echo "<script type='text/javascript'>alert('failed!')</script>";
    <form action="" method="post">
      Name:<input type="text" id="name" name="name"/>
      <input type="submit" value="submit" name="submit"/>

iPad/iPhone hover problem causes the user to double click a link

Avoid changing of "display" style inside of hover css event. I had "display: block" in hover state. After removing ios went on lins by single tap. By the way it seems that latest IOS updates fixed this "feature"

Android Starting Service at Boot Time , How to restart service class after device Reboot?

First register a receiver in your manifest.xml file:

    <receiver android:name="com.mileagelog.service.Broadcast_PowerUp" >
            <action android:name="android.intent.action.ACTION_POWER_CONNECTED" />
            <action android:name="android.intent.action.ACTION_POWER_DISCONNECTED" />

and then write a broadcast for this receiver like:

public class Broadcast_PowerUp extends BroadcastReceiver {

  public void onReceive(Context context, Intent intent) {
    String action = intent.getAction();

    if (action.equals(Intent.ACTION_POWER_CONNECTED)) {
        Toast.makeText(context, "Service_PowerUp Started",

    } else if (action.equals(Intent.ACTION_POWER_DISCONNECTED)) {

        Toast.makeText(context, "Service_PowerUp Stoped", Toast.LENGTH_LONG)

How to call Oracle MD5 hash function?

@user755806 I do not believe that your question was answered. I took your code but used the 'foo' example string, added a lower function and also found the length of the hash returned. In sqlplus or Oracle's sql developer Java database client you can use this to call the md5sum of a value. The column formats clean up the presentation.

column hash_key format a34;
column hash_key_len format 999999;
select dbms_obfuscation_toolkit.md5(
          input => UTL_RAW.cast_to_raw('foo')) as hash_key,
          input => UTL_RAW.cast_to_raw('foo'))) as hash_key_len
 from dual;

The result set

HASH_KEY                           HASH_KEY_LEN
---------------------------------- ------------
acbd18db4cc2f85cedef654fccc4a4d8             32

is the same value that is returned from a Linux md5sum command.

echo -n foo | md5sum
acbd18db4cc2f85cedef654fccc4a4d8  -
  1. Yes you can call or execute the sql statement directly in sqlplus or sql developer. I tested the sql statement in both clients against 11g.
  2. You can use any C, C#, Java or other programming language that can send a statement to the database. It is the database on the other end of the call that needs to be able to understand the sql statement. In the case of 11 g, the code will work.
  3. @tbone provides an excellent warning about the deprecation of the dbms_obfuscation_toolkit. However, that does not mean your code is unusable in 12c. It will work but you will want to eventually switch to dbms_crypto package. dbms_crypto is not available in my version of 11g.

How to create an Oracle sequence starting with max value from a table?

If you can use PL/SQL, try (EDIT: Incorporates Neil's xlnt suggestion to start at next higher value):

SELECT 'CREATE SEQUENCE transaction_sequence MINVALUE 0 START WITH '||MAX(trans_seq_no)+1||' INCREMENT BY 1 CACHE 20'
  INTO v_sql
  FROM transaction_log;


Another point to consider: By setting the CACHE parameter to 20, you run the risk of losing up to 19 values in your sequence if the database goes down. CACHEd values are lost on database restarts. Unless you're hitting the sequence very often, or, you don't care that much about gaps, I'd set it to 1.

One final nit: the values you specified for CACHE and INCREMENT BY are the defaults. You can leave them off and get the same result.

Static Final Variable in Java

In first statement you define variable, which common for all of the objects (class static field).

In the second statement you define variable, which belongs to each created object (a lot of copies).

In your case you should use the first one.

The localhost page isn’t working localhost is currently unable to handle this request. HTTP ERROR 500

It maybe solve your problem, check your files access level

$ sudo chmod -R 777 /"your files location"

What is meant with "const" at end of function declaration?

Bar is guaranteed not to change the object it is being invoked on. See the section about const correctness in the C++ FAQ, for example.

DynamoDB vs MongoDB NoSQL

For quick overview comparisons, I really like this website, that has many comparison pages, eg AWS DynamoDB vs MongoDB;

What is a semaphore?

Mutex: exclusive-member access to a resource

Semaphore: n-member access to a resource

That is, a mutex can be used to syncronize access to a counter, file, database, etc.

A sempahore can do the same thing but supports a fixed number of simultaneous callers. For example, I can wrap my database calls in a semaphore(3) so that my multithreaded app will hit the database with at most 3 simultaneous connections. All attempts will block until one of the three slots opens up. They make things like doing naive throttling really, really easy.

Checking if form has been submitted - PHP


How to close Browser Tab After Submitting a Form?

try onsubmit="submit(); window.close()"

ConnectionTimeout versus SocketTimeout

A connection timeout occurs only upon starting the TCP connection. This usually happens if the remote machine does not answer. This means that the server has been shut down, you used the wrong IP/DNS name, wrong port or the network connection to the server is down.

A socket timeout is dedicated to monitor the continuous incoming data flow. If the data flow is interrupted for the specified timeout the connection is regarded as stalled/broken. Of course this only works with connections where data is received all the time.

By setting socket timeout to 1 this would require that every millisecond new data is received (assuming that you read the data block wise and the block is large enough)!

If only the incoming stream stalls for more than a millisecond you are running into a timeout.

How to save S3 object to a file using boto3

# Preface: File is json with contents: {'name': 'Android', 'status': 'ERROR'}

import boto3
import io

s3 = boto3.resource('s3')

obj = s3.Object('my-bucket', 'key-to-file.json')
data = io.BytesIO()

# object is now a bytes string, Converting it to a dict:
new_dict = json.loads(data.getvalue().decode("utf-8"))

# Should print "Error"

How to pass 2D array (matrix) in a function in C?

I don't know what you mean by "data dont get lost". Here's how you pass a normal 2D array to a function:

void myfunc(int arr[M][N]) { // M is optional, but N is required

int main() {
  int somearr[M][N];

Best way to get the max value in a Spark dataframe column

Another way of doing it:"A")).alias("MAX")).limit(1).collect()[0].MAX

On my data, I got this benchmarks:"A")).alias("MAX")).limit(1).collect()[0].MAX
CPU times: user 2.31 ms, sys: 3.31 ms, total: 5.62 ms
Wall time: 3.7 s"A").rdd.max()[0]
CPU times: user 23.2 ms, sys: 13.9 ms, total: 37.1 ms
Wall time: 10.3 s

df.agg({"A": "max"}).collect()[0][0]
CPU times: user 0 ns, sys: 4.77 ms, total: 4.77 ms
Wall time: 3.75 s

All of them give the same answer

Change the selected value of a drop-down list with jQuery

Just an FYI, you don't need to use CSS classes to accomplish this.

You can write the following line of code to get the correct control name on the client:

$("#<%= statusDDL.ClientID %>").val("2");

ASP.NET will render the control ID correctly inside the jQuery.

NSURLErrorDomain error codes description

I was unable to find name of an error for given code when developing in Swift. For that reason I paste minus codes for NSURLErrorDomain taken from NSURLError.h

    @enum NSURL-related Error Codes
    @abstract Constants used by NSError to indicate errors in the NSURL domain
    NSURLErrorUnknown =             -1,
    NSURLErrorCancelled =           -999,
    NSURLErrorBadURL =              -1000,
    NSURLErrorTimedOut =            -1001,
    NSURLErrorUnsupportedURL =          -1002,
    NSURLErrorCannotFindHost =          -1003,
    NSURLErrorCannotConnectToHost =         -1004,
    NSURLErrorNetworkConnectionLost =       -1005,
    NSURLErrorDNSLookupFailed =         -1006,
    NSURLErrorHTTPTooManyRedirects =        -1007,
    NSURLErrorResourceUnavailable =         -1008,
    NSURLErrorNotConnectedToInternet =      -1009,
    NSURLErrorRedirectToNonExistentLocation =   -1010,
    NSURLErrorBadServerResponse =       -1011,
    NSURLErrorUserCancelledAuthentication =     -1012,
    NSURLErrorUserAuthenticationRequired =  -1013,
    NSURLErrorZeroByteResource =        -1014,
    NSURLErrorCannotDecodeRawData =             -1015,
    NSURLErrorCannotDecodeContentData =         -1016,
    NSURLErrorCannotParseResponse =             -1017,
    NSURLErrorAppTransportSecurityRequiresSecureConnection NS_ENUM_AVAILABLE(10_11, 9_0) = -1022,
    NSURLErrorFileDoesNotExist =        -1100,
    NSURLErrorFileIsDirectory =         -1101,
    NSURLErrorNoPermissionsToReadFile =     -1102,
    NSURLErrorDataLengthExceedsMaximum NS_ENUM_AVAILABLE(10_5, 2_0) =   -1103,

    // SSL errors
    NSURLErrorSecureConnectionFailed =      -1200,
    NSURLErrorServerCertificateHasBadDate =     -1201,
    NSURLErrorServerCertificateUntrusted =  -1202,
    NSURLErrorServerCertificateHasUnknownRoot = -1203,
    NSURLErrorServerCertificateNotYetValid =    -1204,
    NSURLErrorClientCertificateRejected =   -1205,
    NSURLErrorClientCertificateRequired =   -1206,
    NSURLErrorCannotLoadFromNetwork =       -2000,

    // Download and file I/O errors
    NSURLErrorCannotCreateFile =        -3000,
    NSURLErrorCannotOpenFile =          -3001,
    NSURLErrorCannotCloseFile =         -3002,
    NSURLErrorCannotWriteToFile =       -3003,
    NSURLErrorCannotRemoveFile =        -3004,
    NSURLErrorCannotMoveFile =          -3005,
    NSURLErrorDownloadDecodingFailedMidStream = -3006,
    NSURLErrorDownloadDecodingFailedToComplete =-3007,

    NSURLErrorInternationalRoamingOff NS_ENUM_AVAILABLE(10_7, 3_0) =         -1018,
    NSURLErrorCallIsActive NS_ENUM_AVAILABLE(10_7, 3_0) =                    -1019,
    NSURLErrorDataNotAllowed NS_ENUM_AVAILABLE(10_7, 3_0) =                  -1020,
    NSURLErrorRequestBodyStreamExhausted NS_ENUM_AVAILABLE(10_7, 3_0) =      -1021,

    NSURLErrorBackgroundSessionRequiresSharedContainer NS_ENUM_AVAILABLE(10_10, 8_0) = -995,
    NSURLErrorBackgroundSessionInUseByAnotherProcess NS_ENUM_AVAILABLE(10_10, 8_0) = -996,
    NSURLErrorBackgroundSessionWasDisconnected NS_ENUM_AVAILABLE(10_10, 8_0)= -997,

Want custom title / image / description in facebook share link from a flash app

I think this site has the solution, i will test it now. It Seems like facebook has changed the parameters of share.php so, in order to customize share window text and images you have to put parameters in a "p" array.

Check it out.

Tomcat 7 "SEVERE: A child container failed during start"

I have seen this exception while tomcat started and it almost took many hours to figure out the reason. Finally I found out that there were some Spring JARs of a lower version in the lib folder in addition to the Spring jars in the Maven dependencies. The JARs in the lib were automatically added by Eclipse when I added a new Spring Rest controller. I removed those from the lib folder and then let Maven handle the JARs/dependancies and it was fine. Bottom line is if the JARS managed by maven and jars in the WEB-INF/lib causes a classpath issues, you may encounter this error.

How to declare a global variable in JavaScript

Here is a basic example of a global variable that the rest of your functions can access. Here is a live example for you:

var myVariable = 'Hello';
alert('value: ' + myVariable);
alert('value: ' + myVariable);
alert('value: ' + myVariable);

function myFunction1() {
    myVariable = 'Hello 1';

function myFunction2() {
    myVariable = 'Hello 2';

If you are doing this within a jQuery ready() function then make sure your variable is inside the ready() function along with your other functions.

Show message box in case of exception

           // your code
        catch (Exception w)
            MessageDialog msgDialog = new MessageDialog(w.ToString());

Broken references in Virtualenvs

If this was caused by a brew upgrade that upgraded its Python, and you're ok with downgrading to the previous version, try brew switch python [previous version], eg brew switch python 3.6.5. From here.

Extract substring from a string

you can use this code

    public static String getSubString(String mainString, String lastString, String startString) {
    String endString = "";
    int endIndex = mainString.indexOf(lastString);
    int startIndex = mainString.indexOf(startString);
    Log.d("message", "" + mainString.substring(startIndex, endIndex));
    endString = mainString.substring(startIndex, endIndex);
    return endString;

in this mainString is a Super "I_AmANDROID.Devloper" and lastString is a string like"." and startString is like"_". so this function returns "AmANDROID". enjoy your code time.:)

Split string into individual words Java

Yet another method, using StringTokenizer :

String s = "I want to walk my dog";
StringTokenizer tokenizer = new StringTokenizer(s);

while(tokenizer.hasMoreTokens()) {

jQuery - Dynamically Create Button and Attach Event Handler

You were just adding the html string. Not the element you created with a click event listener.

Try This:

    <script type="text/javascript" src=""></script>
    <table id="addNodeTable">
                Row 1
        <tr >
                Row 2
<script type="text/javascript">
    $(document).ready(function() {
        var test = $('<button>Test</button>').click(function () {
        $("#addNodeTable tr:last").append('<tr><td></td></tr>').find("td:last").append(test);


Pretty Printing a pandas dataframe

A simple approach is to output as html, which pandas does out of the box:


How to create a library project in Android Studio and an application project that uses the library project

Documentation Way

This is the recommended way as per the advice given in the Android Studio documentation.

Create a library module

Create a new project to make your library in. Click File > New > New Module > Android Library > Next > (choose name) > Finish. Then add whatever classes and resourced you want to your library.

When you build the module an AAR file will be created. You can find it in project-name/module-name/build/outputs/aar/.

Add your library as a dependency

You can add your library as a dependency to another project like this:

  1. Import your library AAR file with File > New Module > Import .JAR/.AAR Package > Next > (choose file location) > Finish. (Don't import the code, otherwise it will be editable in too many places.)
  2. In the settings.gradle file, make sure your library name is there.

    include ':app', ':my-library-module'
  3. In the app's build.gradle file, add the compile line to the dependencies section:

    dependencies {
        compile project(":my-library-module")
  4. You will be prompted to sync your project with gradle. Do it.

That's it. You should be able to use your library now.


If you want to make your library easily available to a larger audience, consider using JitPac or JCenter.

CSS how to make an element fade in and then fade out?

Use css @keyframes

.elementToFadeInAndOut {
    opacity: 1;
    animation: fade 2s linear;

@keyframes fade {
  0%,100% { opacity: 0 }
  50% { opacity: 1 }

here is a DEMO

.elementToFadeInAndOut {_x000D_
    height: 200px;_x000D_
    background: red;_x000D_
    -webkit-animation: fadeinout 4s linear forwards;_x000D_
    animation: fadeinout 4s linear forwards;_x000D_
@-webkit-keyframes fadeinout {_x000D_
  0%,100% { opacity: 0; }_x000D_
  50% { opacity: 1; }_x000D_
@keyframes fadeinout {_x000D_
  0%,100% { opacity: 0; }_x000D_
  50% { opacity: 1; }_x000D_
<div class=elementToFadeInAndOut></div>

Reading: Using CSS animations

You can clean the code by doing this:

.elementToFadeInAndOut {_x000D_
    height: 200px;_x000D_
    background: red;_x000D_
    -webkit-animation: fadeinout 4s linear forwards;_x000D_
    animation: fadeinout 4s linear forwards;_x000D_
    opacity: 0;_x000D_
@-webkit-keyframes fadeinout {_x000D_
  50% { opacity: 1; }_x000D_
@keyframes fadeinout {_x000D_
  50% { opacity: 1; }_x000D_
<div class=elementToFadeInAndOut></div>

How do we change the URL of a working GitLab install?

There are detailed notes on this that helped me completely, located here.

Jonathon Reinhart has already answered with the key bit, to edit /etc/gitlab/gitlab.rb, alter the external_url and then run sudo gitlab-ctl reconfigure; sudo gitlab-ctl restart

However I needed to go a bit further and docs I linked above explained it. So what I ended up with looks like:

external_url ''
nginx['ssl_certificate'] = "/www/ssl/"
nginx['ssl_certificate_key'] = "/www/ssl/"
nginx['proxy_set_headers'] = {
 "X-Forwarded-Proto" => "http",

Above, I've explicitly declared where my SSL goodies are on this server. And that's of course followed by

sudo gitlab-ctl reconfigure
sudo gitlab-ctl restart

Also, when you switch the omnibus package to https, the bundled nginx will only serve on port 443. Since all my stuff is reached via reverse proxy, this part was potentially significant.

As I went through this, I screwed something up and it helpful to find the actual nginx logs, this lead me there:

sudo gitlab-ctl tail nginx

how to drop database in sqlite?

SQLite database FAQ: How do I drop a SQLite database?

People used to working with other databases are used to having a "drop database" command, but in SQLite there is no similar command. The reason? In SQLite there is no "database server" -- SQLite is an embedded database, and your database is entirely contained in one file. So there is no need for a SQLite drop database command.

To "drop" a SQLite database, all you have to do is delete the SQLite database file you were accessing.

copy from

Changing MongoDB data store directory

In debian/ubuntu, you'll need to edit the /etc/init.d/mongodb script. Really, this file should be pulling the settings from /etc/mongodb.conf but it doesn't seem to pull the default directory (probably a bug)

This is a bit of a hack, but adding these to the script made it start correctly:




DAEMON_OPTS=${DAEMON_OPTS:-"--unixSocketPrefix=$RUNDIR --config $CONF run"}


DAEMON_OPTS=${DAEMON_OPTS:-"--unixSocketPrefix=$RUNDIR --dbpath $DBDIR --config $CONF run"}

Skip first couple of lines while reading lines in Python file

If it's a table.

pd.read_table("path/to/file", sep="\t", index_col=0, skiprows=17)

read file in classpath

Change . to / as the path separator and use getResourceAsStream:

reader = new BufferedReader(new InputStreamReader(


reader = new BufferedReader(new InputStreamReader(

Note the leading slash when using Class.getResourceAsStream() vs ClassLoader.getResourceAsStream. getSystemResourceAsStream uses the system classloader which isn't what you want.

I suspect that using slashes instead of dots would work for ClassPathResource too.

How to get a Color from hexadecimal Color String

XML file saved at res/values/colors.xml:

<?xml version="1.0" encoding="utf-8"?>
   <color name="opaque_red">#f00</color>
   <color name="translucent_red">#80ff0000</color>

This application code retrieves the color resource:

Resources res = getResources();
int color = res.getColor(R.color.opaque_red);

This layout XML applies the color to an attribute:


How to call on a function found on another file?

Small addition to @user995502's answer on how to run the program.

g++ player.cpp main.cpp -o main.out && ./main.out

Flask Error: "Method Not Allowed The method is not allowed for the requested URL"

I had the same problem, and my solving was to replace :

return redirect(url_for('index'))


return render_template('indexo.html',data=Todos.query.all())

in my POST and DELETE route.

Checking if a string is empty or null in Java

You can leverage Apache Commons StringUtils.isEmpty(str), which checks for empty strings and handles null gracefully.


System.out.println(StringUtils.isEmpty("")); // true
System.out.println(StringUtils.isEmpty(null)); // true

Google Guava also provides a similar, probably easier-to-read method: Strings.isNullOrEmpty(str).


System.out.println(Strings.isNullOrEmpty("")); // true
System.out.println(Strings.isNullOrEmpty(null)); // true

When you use 'badidea' or 'thisisunsafe' to bypass a Chrome certificate/HSTS error, does it only apply for the current site?

This is specific for each site. So if you type that once, you will only get through that site and all other sites will need a similar type-through.

It is also remembered for that site and you have to click on the padlock to reset it (so you can type it again):

enter image description here

Needless to say use of this "feature" is a bad idea and is unsafe - hence the name.

You should find out why the site is showing the error and/or stop using it until they fix it. HSTS specifically adds protections for bad certs to prevent you clicking through them. The fact it's needed suggests there is something wrong with the https connection - like the site or your connection to it has been hacked.

The chrome developers also do change this periodically. They changed it recently from badidea to thisisunsafe so everyone using badidea, suddenly stopped being able to use it. You should not depend on it. As Steffen pointed out in the comments below, it is available in the code should it change again though they now base64 encode it to make it more obscure. The last time they changed they put this comment in the commit:

Rotate the interstitial bypass keyword

The security interstitial bypass keyword hasn't changed in two years and awareness of the bypass has been increased in blogs and social media. Rotate the keyword to help prevent misuse.

I think the message from the Chrome team is clear - you should not use it. It would not surprise me if they removed it completely in future.

If you are using this when using a self-signed certificate for local testing then why not just add your self-signed certificate certificate to your computer's certificate store so you get a green padlock and do not have to type this? Note Chrome insists on a SAN field in certificates now so if just using the old subject field then even adding it to the certificate store will not result in a green padlock.

If you leave the certificate untrusted then certain things do not work. Caching for example is completely ignored for untrusted certificates. As is HTTP/2 Push.

HTTPS is here to stay and we need to get used to using it properly - and not bypassing the warnings with a hack that is liable to change and doesn't work the same as a full HTTPS solution.

“Origin null is not allowed by Access-Control-Allow-Origin” error for request made by application running from a file:// URL

As long as the requested server supports the JSON data format, use the JSONP (JSON Padding) interface. It allows you to make external domain requests without proxy servers or fancy header stuff.

jQuery If DIV Doesn't Have Class "x"

jQuery has the hasClass() function that returns true if any element in the wrapped set contains the specified class

if (!$(this).hasClass("selected")) {
    //do stuff

Take a look at my example of use

  • If you hover over a div, it fades as normal speed to 100% opacity if the div does not contain the 'selected' class
  • If you hover out of a div, it fades at slow speed to 30% opacity if the div does not contain the 'selected' class
  • Clicking the button adds 'selected' class to the red div. The fading effects no longer work on the red div

Here is the code for it

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<html xmlns="" xml:lang="en" lang="en">
<script src=""></script>
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<style type="text/css" media="screen">
body { background-color: #FFF; font: 16px Helvetica, Arial; color: #000; }

<!-- jQuery code here -->
<script type="text/javascript">
$(function() {

$('#myButton').click(function(e) {

$('.thumbs').bind('click',function(e) { alert('You clicked ' + ); } );

$('.thumbs').hover(fadeItIn, fadeItOut);


function fadeItIn(e) {
if (!$('selected')) 
    $('normal', 1.0); 

function fadeItOut(e) { 
  if (!$('selected'))
    $('slow', 0.3); 

<div id="div1" class="thumbs" style=" background-color: #0f0; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both;"> 
One div with a thumbs class
<div id="div2" class="thumbs" style=" background-color: #f00; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both;">
Another one with a thumbs class
<input type="button" id="myButton" value="add 'selected' class to red div" />


this is just a guess, but are you trying to achieve something like this?

  • Both divs start at 30% opacity
  • Hovering over a div fades to 100% opacity, hovering out fades back to 30% opacity. Fade effects only work on elements that don't have the 'selected' class
  • Clicking a div adds/removes the 'selected' class

jQuery Code is here-

$(function() {

$('.thumbs').bind('click',function(e) { $('selected'); } );
$('.thumbs').hover(fadeItIn, fadeItOut);
$('.thumbs').css('opacity', 0.3);


function fadeItIn(e) {
if (!$('selected')) 
    $('normal', 1.0); 

function fadeItOut(e) { 
  if (!$('selected'))
    $('slow', 0.3); 

<div id="div1" class="thumbs" style=" background-color: #0f0; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both; cursor:pointer;"> 
One div with a thumbs class
<div id="div2" class="thumbs" style=" background-color: #f00; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both; cursor:pointer;">
Another one with a thumbs class

Difference between uint32 and uint32_t

uint32_t is defined in the standard, in

18.4.1 Header <cstdint> synopsis [cstdint.syn]

namespace std {
typedef unsigned integer type uint32_t; // optional

uint32 is not, it's a shortcut provided by some compilers (probably as typedef uint32_t uint32) for ease of use.

Return string Input with parse.string

As you see in an error error: cannot find symbol return String.parseString(input); there is no method parseString in String class. There is no need to parse it as long as JOptionPane.showInputDialog(prompt); already returns a string.

Python list directory, subdirectory, and files

Couldn't comment so writing answer here. This is the clearest one-line I have seen:

import os
[os.path.join(path, name) for path, subdirs, files in os.walk(root) for name in files]

XSLT equivalent for JSON

it is very possible to convert JSON using XSLT: you need JSON2SAX deserializer and SAX2JSON serializer.

Sample code in Java:

Random number from a range in a Bash Script

Or on OS-X the following works for me:

$ gsort --random-sort

Finding which process was killed by Linux OOM killer

Try this out:

grep "Killed process" /var/log/syslog

'Access denied for user 'root'@'localhost' (using password: NO)'

Firstly, go to the folder support-files on terminal, and start the server by mysql.server start, Secondly, go to the folder bin on terminal or type /usr/local/mysql/bin/mysqladmin -u root -p password

It would ask you for the old temporary password which was given to you while installing Mysql, type that and type in your new password and it would work.

Is there a Visual Basic 6 decompiler?

I have used VB Decompiler Lite ( in the past, and although it does not give you the original source code, it does give you a lot of information such as method names, some variable strings, etc. With more knowledge (or with the full version) it might be possible to get even more than this.

Get name of current script in Python

all that answers are great, but have some problems You might not see at the first glance.

lets define what we want - we want the name of the script that was executed, not the name of the current module - so __file__ will only work if it is used in the executed script, not in an imported module. sys.argv is also questionable - what if your program was called by pytest ? or pydoc runner ? or if it was called by uwsgi ?

and - there is a third method of getting the script name, I havent seen in the answers - You can inspect the stack.

Another problem is, that You (or some other program) can tamper around with sys.argv and __main__.__file__ - it might be present, it might be not. It might be valid, or not. At least You can check if the script (the desired result) exists !

the library lib_programname does exactly that :

  • check if __main__ is present
  • check if __main__.__file__ is present
  • does give __main__.__file__ a valid result (does that script exist ?)
  • if not: check sys.argv:
  • is there pytest, docrunner, etc in the sys.argv ? --> if yes, ignore that
  • can we get a valid result here ?
  • if not: inspect the stack and get the result from there possibly
  • if also the stack does not give a valid result, then throw an Exception.

by that way, my solution is working so far with test, uwsgi, pytest, pycharm pytest , pycharm docrunner (doctest), dreampie, eclipse

there is also a nice blog article about that problem from Dough Hellman, "Determining the Name of a Process from Python"

BTW, it will change again in python 3.9 : the file attribute of the main module became an absolute path, rather than a relative path. These paths now remain valid after the current directory is changed by os.chdir()

So I rather want to take care of one small module, instead of skimming my codebase if it should be changed somewere ...

Disclaimer: I'm the author of the lib_programname library.

MySQL the right syntax to use near '' at line 1 error

the problem is because you have got the query over multiple lines using the " " that PHP is actually sending all the white spaces in to MySQL which is causing it to error out.

Either put it on one line or append on each line :o)

Sqlyog must be trimming white spaces on each line which explains why its working.


$qr2="INSERT INTO wp_bp_activity
 (this stuff)component,
     (is)      `type`,
    (a)        `action`,
  (problem)  content,

No MediaTypeFormatter is available to read an object of type 'String' from content with media type 'text/plain'

Try using ReadAsStringAsync() instead.

 var foo = resp.Content.ReadAsStringAsync().Result;

The reason why it ReadAsAsync<string>() doesn't work is because ReadAsAsync<> will try to use one of the default MediaTypeFormatter (i.e. JsonMediaTypeFormatter, XmlMediaTypeFormatter, ...) to read the content with content-type of text/plain. However, none of the default formatter can read the text/plain (they can only read application/json, application/xml, etc).

By using ReadAsStringAsync(), the content will be read as string regardless of the content-type.

Git error on git pull (unable to update local ref)

This error with (unable to update local ref) can also happen if you have changed passwords recently and there's some fancy stuff integrating your Windows and Linux logins.

Comparing two byte arrays in .NET

P/Invoke powers activate!

[DllImport("msvcrt.dll", CallingConvention=CallingConvention.Cdecl)]
static extern int memcmp(byte[] b1, byte[] b2, long count);

static bool ByteArrayCompare(byte[] b1, byte[] b2)
    // Validate buffers are the same length.
    // This also ensures that the count does not exceed the length of either buffer.  
    return b1.Length == b2.Length && memcmp(b1, b2, b1.Length) == 0;

Does Python support short-circuiting?

Yep, both and and or operators short-circuit -- see the docs.

Stop MySQL service windows

Easy way to shutdown mySQL server for Windows7 :

My Computer > Manage > Services and Application > Services > select "MySQL 56"(the name depends upon the version of MySQL installed.) three options are present at left top corner. Stop the Service pause the Service Restart the Service

choose Stop the service > to stop the server

Again to start you can come to the same location or we can chose tools options on mySQL GUI Server > Startup/Shutdown > Choose to Startup or Shutdown

PS: some times it is not possible to stop the server from the GUI even though the options are provided. so is the reason the above alternative method is provided.

share the ans. to improve. thanks

How to add a new column to an existing sheet and name it?

Use insert method from range, for example

Sub InsertColumn()
        Columns("C:C").Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
        Range("C1").Value = "Loc"
End Sub

How to use paginator from material angular?

The issue in the original question is that you are not capturing "page" event, to resolve this you need to add (page)='yourEventHandler($event)' as an attribute in the md-paginator tag.

check a working example here

You can also check the API docs here

How to make sure you don't get WCF Faulted state exception?

If the transfer mode is Buffered then make sure that the values of MaxReceivedMessageSize and MaxBufferSize is same. I just resolved the faulted state issue this way after grappling with it for hours and thought i'll post it here if it helps someone.

How to use Bootstrap in an Angular project?

If you plan on using Bootstrap 4 which is required with the angular-ui team's ng-bootstrap that is mentioned in this thread, you'll want to use this instead (NOTE: you don't need to include the JS file):

  <link rel="stylesheet" href="" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">

You can also reference this locally after running npm install [email protected] --save by pointing to the file in your styles.scss file, assuming you're using SASS:

@import '../../node_modules/bootstrap/dist/css/bootstrap.min.css';

How to expand 'select' option width after the user wants to select an option


function PopulateDropdown() {
        type: "POST",
        url: "../CommonWebService.asmx/GetData",
        data: "{}",
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (msg) {
            $.each(msg.d, function () {
            $("select[id^='MyDropDown']").css("width", "auto");  
        error: function (e1) {
            alert("Error - " + e1.toString());

The below code will solve your problem of dropdownlist width by adding this code after insertion of Data to dropdownlist.

$("select[id^='MyDropDown']").css("width", "auto");

Angular - Use pipes in services and components

This answer is now outdated

recommend using DI approach from other answers instead of this approach

Original answer:

You should be able to use the class directly

new DatePipe().transform(myDate, 'yyyy-MM-dd');

For instance

var raw = new Date(2015, 1, 12);
var formatted = new DatePipe().transform(raw, 'yyyy-MM-dd');

Eclipse EGit Checkout conflict with files: - EGit doesn't want to continue

Right click on the project and select [replace with] -> Head Revision .Now select pull changes in current branch or pull changes from upstream.

Angular 2 change event on every keypress

The secret event that keeps angular ngModel synchronous is the event call input. Hence the best answer to your question should be:

<input type="text" [(ngModel)]="mymodel" (input)="valuechange($event)" />

How to use a PHP class from another file?

In this case, it appears that you've already included the file somewhere. But for class files, you should really "include" them using require_once to avoid that sort of thing; it won't include the file if it already has been. (And you should usually use require[_once], not include[_once], the difference being that require will cause a fatal error if the file doesn't exist, instead of just issuing a warning.)

Convert Json Array to normal Java list

How about using java.util.Arrays?

List<String> list = Arrays.asList((String[])jsonArray.toArray())

Comparing Class Types in Java

If you had two Strings and compared them using == by calling the getClass() method on them, it would return true. What you get is a reference on the same object.

This is because they are both references on the same class object. This is true for all classes in a java application. Java only loads the class once, so you have only one instance of a given class at a given time.

String hello  = "Hello";
String world = "world";

if (hello.getClass() == world.getClass()) {
} // prints true

Warning: mysqli_real_escape_string() expects exactly 2 parameters, 1 given... what I do wrong?

The following works perfectly:-


Now, the $connect is my variable containing my connection to the database. You only left out the connection variable. Include it and it shall work perfectly.

PostgreSQL, checking date relative to "today"

select * from mytable where mydate > now() - interval '1 year';

If you only care about the date and not the time, substitute current_date for now()

What's the difference between TRUNCATE and DELETE in SQL

By issuing a TRUNCATE TABLE statement, you are instructing SQL Server to delete every record within a table, without any logging or transaction processing taking place.

How to get JS variable to retain value after page refresh?

You can do that by storing cookies on client side.

How to pass command line arguments to a shell alias?

You cannot in ksh, but you can in csh.

alias mkcd 'mkdir \!^; cd \!^1'

In ksh, function is the way to go. But if you really really wanted to use alias:

alias mkcd='_(){ mkdir $1; cd $1; }; _'

How to select element using XPATH syntax on Selenium for Python?

Check this blog by Martin Thoma. I tested the below code on MacOS Mojave and it worked as specified.

> def get_browser():
>     """Get the browser (a "driver")."""
>     # find the path with 'which chromedriver'
>     path_to_chromedriver = ('/home/moose/GitHub/algorithms/scraping/'
>                             'venv/bin/chromedriver')
>     download_dir = "/home/moose/selenium-download/"
>     print("Is directory: {}".format(os.path.isdir(download_dir)))
>     from import Options
>     chrome_options = Options()
>     chrome_options.add_experimental_option('prefs', {
>         "plugins.plugins_list": [{"enabled": False,
>                                   "name": "Chrome PDF Viewer"}],
>         "download": {
>             "prompt_for_download": False,
>             "default_directory": download_dir
>         }
>     })
>     browser = webdriver.Chrome(path_to_chromedriver,
>                                chrome_options=chrome_options)
>     return browser

Using a Python subprocess call to invoke a Python script

Windows? Unix?

Unix will need a shebang and exec attribute to work:

#!/usr/bin/env python

as the first line of script and:

chmod u+x

at command-line or


as mentioned previously.

Windows should work if you add the shell=True parameter to the "call" call.

Why can't DateTime.ParseExact() parse "9/1/2009" using "M/d/yyyy"

Set DateTimePicker's Format property to custom and CustomFormat prperty to M/dd/yyyy.

Perform an action in every sub-directory using Bash

the accepted answer will break on white spaces if the directory names have them, and the preferred syntax is $() for bash/ksh. Use GNU find -exec option with +; eg

find .... -exec mycommand +; #this is same as passing to xargs

or use a while loop

find .... | while read -r D
    # use variable `D` or whatever variable name you defined instead here

make script execution to unlimited

You'll have to set it to zero. Zero means the script can run forever. Add the following at the start of your script:

ini_set('max_execution_time', 0);

Refer to the PHP documentation of max_execution_time

Note that:


will have the same effect.

What's the difference between a web site and a web application?

Semantics.... generally a website contains static HTML pages and a web application performs some type of work. For example, a website for a realtor may give information about the realtor, where a web application for the realtor may list current properties and manage the contact information for the realtor themselves.

How do I compile C++ with Clang?

Open a Terminal window and navigate to your project directory. Run these sets of commands, depending on which compiler you have installed:

To compile multiple C++ files using clang++:

$ clang++ *.cpp 
$ ./a.out 

To compile multiple C++ files using g++:

$ g++ -c *.cpp 
$ g++ -o temp.exe *.o
$ ./temp.exe

PHP "pretty print" json_encode

PHP has JSON_PRETTY_PRINT option since 5.4.0 (release date 01-Mar-2012).

This should do the job:

$json = json_decode($string);
echo json_encode($json, JSON_PRETTY_PRINT);


Note: Don't forget to echo "<pre>" before and "</pre>" after, if you're printing it in HTML to preserve formatting ;)

Spring Boot how to hide passwords in properties file

UPDATE: I noticed folks down-voting this, so I have to say that although this is not an ideal solution, but this works and acceptable in some use-cases. Cloudfoundry uses Environment variables to inject credentials when a Service is binded to an application. More info

And also if your system is not shared, then for local development this is also acceptable. Of course, the more safe and secure way is explained in Answer by @J-Alex.


If you want to hide your passwords then the easiest solution is to use Environment variables in file or directly in your code.



Then in your configuration class:

private Environment environment;

[...]//Inside a method

In your configuration class:

private String herokuPath;

[...]//Inside a method

Note: You might have to restart after setting the environment variable. For windows:

In Windows

Refer this Documentation for more info.

How can I change Eclipse theme?

In the eclipse Version: 2019-09 R (4.13.0) on windows Go to Window > preferences > Appearance Select the required theme for dark theme to choose Dark and click on Ok. enter image description here

What is the difference between sscanf or atoi to convert a string to an integer?

Combining R.. and PickBoy answers for brevity

long strtol (const char *String, char **EndPointer, int Base)

// examples
strtol(s, NULL, 10);
strtol(s, &s, 10);

Set variable in jinja

Nice shorthand for Multiple variable assignments

{% set label_cls, field_cls = "col-md-7", "col-md-3" %}

How can I change the user on Git Bash?

For Mac Users

I am using Mac and I was facing the same problem while I was trying to push a project from Android Studio. The reason for that is another user had previously logged into GitHub and his credentials were saved in Keychain Access.

The solution is to delete all the information store in keychain for that process

enter image description here

How do you send a Firebase Notification to all devices via CURL?

For anyone wondering how to do it in cordova hybrid app:

  • go to index.js -> inside the function onDeviceReady() write :


(It's important to write it at the top of the function!)

  • then, in the same file (index.js) find :

    function subscribe(){

     FirebasePlugin.subscribe("write_here_your_topic", function(){
         logError("Failed to subscribe to topic", error);

and write your own topic here -> "write_here_your_topic"

How to checkout in Git by date?

Going further with the rev-list option, if you want to find the most recent merge commit from your master branch into your production branch (as a purely hypothetical example):

git checkout `git rev-list -n 1 --merges --first-parent --before="2012-01-01" production`

I needed to find the code that was on the production servers as of a given date. This found it for me.

Is there a simple way to use button to navigate page as a link does in angularjs

With bootstrap you can use

<a href="#/new-page.html" class="btn btn-primary">

Loop through files in a folder using VBA?

Dir takes wild cards so you could make a big difference adding the filter for test up front and avoiding testing each file

Sub LoopThroughFiles()
    Dim StrFile As String
    StrFile = Dir("c:\testfolder\*test*")
    Do While Len(StrFile) > 0
        Debug.Print StrFile
        StrFile = Dir
End Sub

One or more types required to compile a dynamic expression cannot be found. Are you missing references to Microsoft.CSharp.dll and System.Core.dll?

Make sure that your project is targeting the .NET framework 4.0. Visual Studio 2010 supports .NET 3.5 framework target also, but .NET 3.5 does not support the dynamic keyword.

You can adjust the framework version in the project properties. See for more info.

Declare a const array

As an alternative, to get around the elements-can-be-modified issue with a readonly array, you can use a static property instead. (The individual elements can still be changed, but these changes will only be made on the local copy of the array.)

public static string[] Titles 
        return new string[] { "German", "Spanish", "Corrects", "Wrongs"};

Of course, this will not be particularly efficient as a new string array is created each time.

CSS Change List Item Background Color with Class

1) You can use the !important rule, like this:

  background-color:red !important;

See for more info.

2) In your example you can also get the red background by using ul.nav li.selected instead of just .selected. This makes the selector more specific.

See for more info.

Extracting text from HTML file using Python

I know there's plenty of answers here already but I think newspaper3k also deserves a mention. I recently needed to complete a similar task of extracting the text from articles on the web and this library has done an excellent job of achieving this so far in my tests. It ignores the text found in menu items and side bars as well as any JavaScript that appears on the page as the OP requests.

from newspaper import Article

article = Article(url)

If you already have the HTML files downloaded you can do something like this:

article = Article('')

It even has a few NLP features for summarizing the topics of articles:


Setting an environment variable before a command in Bash is not working for the second command in a pipe

How about exporting the variable, but only inside the subshell?:

(export FOO=bar && somecommand someargs | somecommand2)

Keith has a point, to unconditionally execute the commands, do this:

(export FOO=bar; somecommand someargs | somecommand2)

Difference between "\n" and Environment.NewLine

Depends on the platform. On Windows it is actually "\r\n".

From MSDN:

A string containing "\r\n" for non-Unix platforms, or a string containing "\n" for Unix platforms.

Convert a List<T> into an ObservableCollection<T>

ObservableCollection < T > has a constructor overload which takes IEnumerable < T >

Example for a List of int:

ObservableCollection<int> myCollection = new ObservableCollection<int>(myList);

One more example for a List of ObjectA:

ObservableCollection<ObjectA> myCollection = new ObservableCollection<ObjectA>(myList as List<ObjectA>);

How can I get all a form's values that would be submitted without submitting

If your form tag is like

<form action="" method="post" id="BookPackageForm">

Then fetch the form element by using forms object.

var formEl = document.forms.BookPackageForm;

Get the data from the form by using FormData objects.

var formData = new FormData(formEl);

Get the value of the fields by the form data object.

var name = formData.get('name');

What is the 'instanceof' operator used for in Java?

The java instanceof operator is used to test whether the object is an instance of the specified type (class or subclass or interface).

The instanceof in java is also known as type comparison operator as it compares the instance with type. It returns either true or false. If we apply the instanceof operator with any variable that has null value, it returns false.

From JDK 14+ which includes JEP 305 we can also do "Pattern Matching" for instanceof

Patterns basically test that a value has a certain type, and can extract information from the value when it has the matching type. Pattern matching allows a more clear and efficient expression of common logic in a system, namely the conditional removal of components from objects.

Before Java 14

if (obj instanceof String) {
    String str = (String) obj; // need to declare and cast again the object
    .. str.contains(..) ..
     str = ....

Java 14 enhancements

if (!(obj instanceof String str)) {
    .. str.contains(..) .. // no need to declare str object again with casting
} else {
    .. str....

We can also combine the type check and other conditions together

if (obj instanceof String str && str.length() > 4) {.. str.contains(..) ..}

The use of pattern matching in instanceof should reduce the overall number of explicit casts in Java programs.

PS: instanceOf will only match when the object is not null, then only it can be assigned to str.

Delete empty rows

I believe that your problem is that you're checking for an empty string using double quotes instead of single quotes. Try just changing to:

DELETE FROM table WHERE edit_user=''

Is there more to an interface than having the correct methods

Interfaces are a way to make your code more flexible. What you do is this:

Ibox myBox=new Rectangle();

Then, later, if you decide you want to use a different kind of box (maybe there's another library, with a better kind of box), you switch your code to:

Ibox myBox=new OtherKindOfBox();

Once you get used to it, you'll find it's a great (actually essential) way to work.

Another reason is, for example, if you want to create a list of boxes and perform some operation on each one, but you want the list to contain different kinds of boxes. On each box you could do:


(assuming IBox has a close() method) even though the actual class of myBox changes depending on which box you're at in the iteration.

Examples of GoF Design Patterns in Java's core libraries

You can find an overview of a lot of design patterns in Wikipedia. It also mentions which patterns are mentioned by GoF. I'll sum them up here and try to assign as many pattern implementations as possible, found in both the Java SE and Java EE APIs.

Creational patterns

Abstract factory (recognizeable by creational methods returning the factory itself which in turn can be used to create another abstract/interface type)

Builder (recognizeable by creational methods returning the instance itself)

Factory method (recognizeable by creational methods returning an implementation of an abstract/interface type)

Prototype (recognizeable by creational methods returning a different instance of itself with the same properties)

Singleton (recognizeable by creational methods returning the same instance (usually of itself) everytime)

Structural patterns

Adapter (recognizeable by creational methods taking an instance of different abstract/interface type and returning an implementation of own/another abstract/interface type which decorates/overrides the given instance)

Bridge (recognizeable by creational methods taking an instance of different abstract/interface type and returning an implementation of own abstract/interface type which delegates/uses the given instance)

  • None comes to mind yet. A fictive example would be new LinkedHashMap(LinkedHashSet<K>, List<V>) which returns an unmodifiable linked map which doesn't clone the items, but uses them. The java.util.Collections#newSetFromMap() and singletonXXX() methods however comes close.

Composite (recognizeable by behavioral methods taking an instance of same abstract/interface type into a tree structure)

Decorator (recognizeable by creational methods taking an instance of same abstract/interface type which adds additional behaviour)

Facade (recognizeable by behavioral methods which internally uses instances of different independent abstract/interface types)

Flyweight (recognizeable by creational methods returning a cached instance, a bit the "multiton" idea)

Proxy (recognizeable by creational methods which returns an implementation of given abstract/interface type which in turn delegates/uses a different implementation of given abstract/interface type)

Behavioral patterns

Chain of responsibility (recognizeable by behavioral methods which (indirectly) invokes the same method in another implementation of same abstract/interface type in a queue)

Command (recognizeable by behavioral methods in an abstract/interface type which invokes a method in an implementation of a different abstract/interface type which has been encapsulated by the command implementation during its creation)

Interpreter (recognizeable by behavioral methods returning a structurally different instance/type of the given instance/type; note that parsing/formatting is not part of the pattern, determining the pattern and how to apply it is)

Iterator (recognizeable by behavioral methods sequentially returning instances of a different type from a queue)

Mediator (recognizeable by behavioral methods taking an instance of different abstract/interface type (usually using the command pattern) which delegates/uses the given instance)

Memento (recognizeable by behavioral methods which internally changes the state of the whole instance)

Observer (or Publish/Subscribe) (recognizeable by behavioral methods which invokes a method on an instance of another abstract/interface type, depending on own state)

State (recognizeable by behavioral methods which changes its behaviour depending on the instance's state which can be controlled externally)

Strategy (recognizeable by behavioral methods in an abstract/interface type which invokes a method in an implementation of a different abstract/interface type which has been passed-in as method argument into the strategy implementation)

Template method (recognizeable by behavioral methods which already have a "default" behaviour defined by an abstract type)

Visitor (recognizeable by two different abstract/interface types which has methods defined which takes each the other abstract/interface type; the one actually calls the method of the other and the other executes the desired strategy on it)

Google Maps v2 - set both my location and zoom in

You cannot animate two things (like zoom in and go to my location) in one google map.
So use move and animate Camera to zoom


How to convert List<string> to List<int>?

I know it's old post, but I thought this is a good addition: You can use List<T>.ConvertAll<TOutput>

List<int> integers = strings.ConvertAll(s => Int32.Parse(s));

Floating point comparison functions for C#

Here is a much-expanded version of Simon Hewitt's class:

/// <summary>
/// Safely converts a <see cref="float"/> to an <see cref="int"/> for floating-point comparisons.
/// </summary>
public struct FloatToInt : IEquatable<FloatToInt>, IEquatable<float>, IEquatable<int>, IComparable<FloatToInt>, IComparable<float>, IComparable<int>
    /// <summary>
    /// Initializes a new instance of the <see cref="FloatToInt"/> class.
    /// </summary>
    /// <param name="floatValue">The <see cref="float"/> value to be converted to an <see cref="int"/>.</param>
    public FloatToInt(float floatValue)
        : this()
        FloatValue = floatValue;

    /// <summary>
    /// Gets the floating-point value as an integer.
    /// </summary>
    public readonly int IntValue;

    /// <summary>
    /// Gets the floating-point value.
    /// </summary>
    public readonly float FloatValue;

    /// <summary>
    /// Indicates whether the current object is equal to another object of the same type.
    /// </summary>
    /// <returns>
    /// true if the current object is equal to the <paramref name="other"/> parameter; otherwise, false.
    /// </returns>
    /// <param name="other">An object to compare with this object.</param>
    public bool Equals(FloatToInt other)
        return other.IntValue == IntValue;

    /// <summary>
    /// Indicates whether the current object is equal to another object of the same type.
    /// </summary>
    /// <returns>
    /// true if the current object is equal to the <paramref name="other"/> parameter; otherwise, false.
    /// </returns>
    /// <param name="other">An object to compare with this object.</param>
    public bool Equals(float other)
        return IntValue == new FloatToInt(other).IntValue;

    /// <summary>
    /// Indicates whether the current object is equal to another object of the same type.
    /// </summary>
    /// <returns>
    /// true if the current object is equal to the <paramref name="other"/> parameter; otherwise, false.
    /// </returns>
    /// <param name="other">An object to compare with this object.</param>
    public bool Equals(int other)
        return IntValue == other;

    /// <summary>
    /// Compares the current object with another object of the same type.
    /// </summary>
    /// <returns>
    /// A value that indicates the relative order of the objects being compared. The return value has the following meanings: Value Meaning Less than zero This object is less than the <paramref name="other"/> parameter.Zero This object is equal to <paramref name="other"/>. Greater than zero This object is greater than <paramref name="other"/>. 
    /// </returns>
    /// <param name="other">An object to compare with this object.</param>
    public int CompareTo(FloatToInt other)
        return IntValue.CompareTo(other.IntValue);

    /// <summary>
    /// Compares the current object with another object of the same type.
    /// </summary>
    /// <returns>
    /// A value that indicates the relative order of the objects being compared. The return value has the following meanings: Value Meaning Less than zero This object is less than the <paramref name="other"/> parameter.Zero This object is equal to <paramref name="other"/>. Greater than zero This object is greater than <paramref name="other"/>. 
    /// </returns>
    /// <param name="other">An object to compare with this object.</param>
    public int CompareTo(float other)
        return IntValue.CompareTo(new FloatToInt(other).IntValue);

    /// <summary>
    /// Compares the current object with another object of the same type.
    /// </summary>
    /// <returns>
    /// A value that indicates the relative order of the objects being compared. The return value has the following meanings: Value Meaning Less than zero This object is less than the <paramref name="other"/> parameter.Zero This object is equal to <paramref name="other"/>. Greater than zero This object is greater than <paramref name="other"/>. 
    /// </returns>
    /// <param name="other">An object to compare with this object.</param>
    public int CompareTo(int other)
        return IntValue.CompareTo(other);

    /// <summary>
    /// Indicates whether this instance and a specified object are equal.
    /// </summary>
    /// <returns>
    /// true if <paramref name="obj"/> and this instance are the same type and represent the same value; otherwise, false.
    /// </returns>
    /// <param name="obj">Another object to compare to. </param><filterpriority>2</filterpriority>
    public override bool Equals(object obj)
        if (ReferenceEquals(null, obj))
            return false;
        if (obj.GetType() != typeof(FloatToInt))
            return false;
        return Equals((FloatToInt)obj);

    /// <summary>
    /// Returns the hash code for this instance.
    /// </summary>
    /// <returns>
    /// A 32-bit signed integer that is the hash code for this instance.
    /// </returns>
    /// <filterpriority>2</filterpriority>
    public override int GetHashCode()
        return IntValue;

    /// <summary>
    /// Implicitly converts from a <see cref="FloatToInt"/> to an <see cref="int"/>.
    /// </summary>
    /// <param name="value">A <see cref="FloatToInt"/>.</param>
    /// <returns>An integer representation of the floating-point value.</returns>
    public static implicit operator int(FloatToInt value)
        return value.IntValue;

    /// <summary>
    /// Implicitly converts from a <see cref="FloatToInt"/> to a <see cref="float"/>.
    /// </summary>
    /// <param name="value">A <see cref="FloatToInt"/>.</param>
    /// <returns>The floating-point value.</returns>
    public static implicit operator float(FloatToInt value)
        return value.FloatValue;

    /// <summary>
    /// Determines if two <see cref="FloatToInt"/> instances have the same integer representation.
    /// </summary>
    /// <param name="left">A <see cref="FloatToInt"/>.</param>
    /// <param name="right">A <see cref="FloatToInt"/>.</param>
    /// <returns>true if the two <see cref="FloatToInt"/> have the same integer representation; otherwise, false.</returns>
    public static bool operator ==(FloatToInt left, FloatToInt right)
        return left.IntValue == right.IntValue;

    /// <summary>
    /// Determines if two <see cref="FloatToInt"/> instances have different integer representations.
    /// </summary>
    /// <param name="left">A <see cref="FloatToInt"/>.</param>
    /// <param name="right">A <see cref="FloatToInt"/>.</param>
    /// <returns>true if the two <see cref="FloatToInt"/> have different integer representations; otherwise, false.</returns>
    public static bool operator !=(FloatToInt left, FloatToInt right)
        return !(left == right);

How do I run Redis on Windows?

you can install Redis by following this article: but for going straight, you can download it by this link: after downloading, go to the directory which you like to put your files,then extract the zip file, then open a command prompt and go to the directory where you extracted your file, then type "redis-server" and hit enter(for opening redis-cli open command and route to redis directory, but instead of "redis-server" execute "redis-cli").

Hex colors: Numeric representation for "transparent"?

Transparency is a property outside the color itself, also known as alpha component. You can't code it as RGB.

If you want a transparent background, you can do this:

background: transparent;

Additionally, I don't know if it might be helpful or not but, you could set the opacity property:

  opacity: 0.5;
  filter: alpha(opacity=50);

You need both in order to get it working in IE and all other decent browsers.

JOptionPane - input dialog box program

After that you have to parse the results. Suppose results are in integers, then

int testint1 = Integer.parse(test1);

Similarly others should be parsed. Now the results should be checked for two higher marks in them, by using if statement After that take out the average. Connection reset

I also had this problem with a Java program trying to send a command on a server via SSH. The problem was with the machine executing the Java code. It didn't have the permission to connect to the remote server. The write() method was doing alright, but the read() method was throwing a Connection reset. I fixed this problem with adding the client SSH key to the remote server known keys.

Image library for Python 3

The "friendly PIL fork" Pillow works on Python 2 and 3. Check out the Github project for support matrix and so on.

AngularJS open modal on button click

Hope this will help you .

Here is Html code:-

    <div ng-controller="MyController" class="container">
      <h1>Modal example</h1>
      <button ng-click="open()" class="btn btn-primary">Test Modal</button>

      <modal title="Login form" visible="showModal">
        <form role="form">


AngularJs code:-

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

mymodal.controller('MyController', function ($scope) {
    $scope.showModal = false;
    $ = function(){
    $scope.showModal = !$scope.showModal;

mymodal.directive('modal', function () {
    return {
      template: '<div class="modal fade">' + 
          '<div class="modal-dialog">' + 
            '<div class="modal-content">' + 
              '<div class="modal-header">' + 
                '<button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>' + 
                '<h4 class="modal-title">{{ title }}</h4>' + 
              '</div>' + 
              '<div class="modal-body" ng-transclude></div>' + 
            '</div>' + 
          '</div>' + 
      restrict: 'E',
      transclude: true,
      link: function postLink(scope, element, attrs) {
        scope.title = attrs.title;

        scope.$watch(attrs.visible, function(value){
          if(value == true)

        $(element).on('', function(){
            scope.$parent[attrs.visible] = true;

        $(element).on('', function(){
            scope.$parent[attrs.visible] = false;

Check this--jsfiddle

How to get the containing form of an input?

I needed to use element.attr('form') instead of element.form.

I use Firefox on Fedora 12.

How to change the bootstrap primary color?

The correct way to change the default primary colour in Bootstrap 4.x using SASS, or any other colours like secondary, success and so on.

Create the following SASS file and import Bootstrap SASS as indicated:

// (Required) Import Bootstrap
@import "bootstrap/functions";
@import "bootstrap/variables";
@import "bootstrap/mixins";

$primary: blue;
$secondary: green;
$my-color: red;

$theme-colors: (
  primary: $primary,
  secondary: $secondary,
  my-color: $my-color

// Add below your SASS or CSS code

// (Required) Import Bootstrap
@import "bootstrap/bootstrap";

JFrame Maximize window

If you're using a JFrame, try this

JFrame frame = new JFrame();

Is there a "null coalescing" operator in JavaScript?

If || as a replacement of C#'s ?? isn't good enough in your case, because it swallows empty strings and zeros, you can always write your own function:

 function $N(value, ifnull) {
    if (value === null || value === undefined)
      return ifnull;
    return value;

 var whatIWant = $N(someString, 'Cookies!');

Get method arguments using Spring AOP?

You have a few options:

First, you can use the JoinPoint#getArgs() method which returns an Object[] containing all the arguments of the advised method. You might have to do some casting depending on what you want to do with them.

Second, you can use the args pointcut expression like so:

// use '..' in the args expression if you have zero or more parameters at that point
@Before("execution(* && args(yourString,..)")

then your method can instead be defined as

public void logBefore(JoinPoint joinPoint, String yourString) 

Webview load html from assets directory

protected void onCreate(Bundle savedInstanceState) {
        WebView wb = new WebView(this);

keep your .html in `asset` folder

How can I read input from the console using the Scanner class in Java?

  1. To read input:

    Scanner scanner = new Scanner(;
    String input = scanner.nextLine();
  2. To read input when you call a method with some arguments/parameters:

    if (args.length != 2) {
        System.err.println("Utilizare: java Grep <fisier> <cuvant>");
    try {
        grep(args[0], args[1]);
    } catch (IOException e) {

Inserting an image with PHP and FPDF

I figured it out, and it's actually pretty straight forward.

Set your variable:

$image1 = "img/products/image1.jpg";

Then ceate a cell, position it, then rather than setting where the image is, use the variable you created above with the following:

$this->Cell( 40, 40, $pdf->Image($image1, $pdf->GetX(), $pdf->GetY(), 33.78), 0, 0, 'L', false );

Now the cell will move up and down with content if other cells around it move.

Hope this helps others in the same boat.

C++ for each, pulling from vector elements

This is how it would be done in a loop in C++(11):

   for (const auto& attack : m_attack)
        if (attack->m_num == input)

There is no for each in C++. Another option is to use std::for_each with a suitable functor (this could be anything that can be called with an Attack* as argument).

Git/GitHub can't push to master

I had this issue after upgrading the Git client, and suddenly my repository could not push.

I found that some old remote had the wrong value of url, even through my currently active remote had the same value for url and was working fine.

But there was also the pushurl param, so adding it for the old remote worked for me:


[remote "origin"]
    url = git://
    fetch = +refs/heads/*:refs/remotes/origin/*
    pushurl = [email protected]:user/repo.git

NOTE: This part of file "config" was unused for ages, but the new client complained about the wrong URL:

[remote "composer"]
    url = git://
    fetch = +refs/heads/*:refs/remotes/composer/*

So I added the pushurl param to the old remote:

[remote "composer"]
    url = git://
    fetch = +refs/heads/*:refs/remotes/composer/*
    pushurl = [email protected]:user/repo.git

Ruby: character to ascii from a string

puts "string".split('').map(&:ord).to_s

What MIME type should I use for CSV?

RFC 7111

There is an RFC which covers it and says to use text/csv.

This RFC updates RFC 4180.


Recently I discovered an explicit mimetype for Excel application/ It was registered with IANA in '96. Note the concerns raised about being at the mercy of the sender and having your machine violated.

Media Type: application/

Name Microsoft Excel (tm)

Required parameters: None

Optional parameters: name

Encoding considerations: base64 preferred

Security considerations: As with most application types this data is intended for interpretation by a program that understands the data on the recipient's system. Recipients need to understand that they are at the "mercy" of the sender, when receiving this type of data, since data will be executed on their system, and the security of their machines can be violated.

OID { org-id ms-files(4) ms-excel (3) }

Object type spreadsheet

Comments This Media Type/OID is used to identify Microsoft Excel generically (i.e., independent of version, subtype, or platform format).

I wasn't aware that vendor extensions were allowed. Check out this answer to find out more - thanks starbeamrainbowlabs for the reference.

Identifier not found error on function call

You have to define void swapCase before the main definition.

using favicon with css

You don't need to - if the favicon is place in the root at favicon.ico, browsers will automatically pick it up.

If you don't see it working, clear your cache etc, it does work without the markup. You only need to use the code if you want to call it something else, or put it on a CDN for instance.

Can you detect "dragging" in jQuery?

For this simplest way is touch start, touch move and touch end. That is working for both PC and touch device just check it in jquery documentation and hope this is the best solution for you. good luck

SQL to add column and comment in table in single command

You can use below query to update or create comment on already created table.


COMMENT ON COLUMN TableName.ColumnName IS 'comment text';


COMMENT ON COLUMN TAB_SAMBANGI.MY_COLUMN IS 'This is a comment on my column...';

PostgreSQL IF statement

From the docs

IF boolean-expression THEN

So in your above example the code should look as follows:

IF select count(*) from orders > 0
  DELETE from orders
  INSERT INTO orders values (1,2,3);

You were missing: END IF;

How to switch between python 2.7 to python 3 from command line?

They are 3 ways you can achieve this using the py command (py-launcher) in python 3, virtual environment or configuring your default python system path. For illustration purpose, you may see tutorial

How to Update a Component without refreshing full page - Angular

To refresh the component at regular intervals I found this the best method. In the ngOnInit method setTimeOut function

ngOnInit(): void {
  setTimeout(() => { this.ngOnInit() }, 1000 * 10)
//10 is the number of seconds

Why can't I find SQL Server Management Studio after installation?

Generally if the installation went smoothly, it will create the desktop icons/folders. Maybe check the installation summary log to see if there's any underlying errors.

It should be located C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Log(date stamp)\

Encrypt and decrypt a String in java

    public String encrypt(String str) {
        try {
            // Encode the string into bytes using utf-8
            byte[] utf8 = str.getBytes("UTF8");

            // Encrypt
            byte[] enc = ecipher.doFinal(utf8);

            // Encode bytes to base64 to get a string
            return new sun.misc.BASE64Encoder().encode(enc);
        } catch (javax.crypto.BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch ( e) {
        return null;

    public String decrypt(String str) {
        try {
            // Decode base64 to get bytes
            byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

            // Decrypt
            byte[] utf8 = dcipher.doFinal(dec);

            // Decode using utf-8
            return new String(utf8, "UTF8");
        } catch (javax.crypto.BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch ( e) {
        return null;

Here's an example that uses the class:

try {
    // Generate a temporary key. In practice, you would save this key.
    // See also Encrypting with DES Using a Pass Phrase.
    SecretKey key = KeyGenerator.getInstance("DES").generateKey();

    // Create encrypter/decrypter class
    DesEncrypter encrypter = new DesEncrypter(key);

    // Encrypt
    String encrypted = encrypter.encrypt("Don't tell anybody!");

    // Decrypt
    String decrypted = encrypter.decrypt(encrypted);
} catch (Exception e) {

How do you configure an OpenFileDialog to select folders?

The Ookii Dialogs for WPF library has a class that provides an implementation of a folder browser dialog for WPF.

Ookii Folder Browser Dialog

There's also a version that works with Windows Forms.

Why does LayoutInflater ignore the layout_width and layout_height layout parameters I've specified?

I've investigated this issue, referring to the LayoutInflater docs and setting up a small sample demonstration project. The following tutorials shows how to dynamically populate a layout using LayoutInflater.

Before we get started see what LayoutInflater.inflate() parameters look like:

  • resource: ID for an XML layout resource to load (e.g., R.layout.main_page)
  • root: Optional view to be the parent of the generated hierarchy (if attachToRoot is true), or else simply an object that provides a set of LayoutParams values for root of the returned hierarchy (if attachToRoot is false.)
  • attachToRoot: Whether the inflated hierarchy should be attached to the root parameter? If false, root is only used to create the correct subclass of LayoutParams for the root view in the XML.

  • Returns: The root View of the inflated hierarchy. If root was supplied and attachToRoot is true, this is root; otherwise it is the root of the inflated XML file.

Now for the sample layout and code.

Main layout (main.xml):

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

Added into this container is a separate TextView, visible as small red square if layout parameters are successfully applied from XML (red.xml):

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

Now LayoutInflater is used with several variations of call parameters

public class InflaterTest extends Activity {

    private View view;

    public void onCreate(Bundle savedInstanceState) {

      ViewGroup parent = (ViewGroup) findViewById(;

      // result: layout_height=wrap_content layout_width=match_parent
      view = LayoutInflater.from(this).inflate(, null);

      // result: layout_height=100 layout_width=100
      view = LayoutInflater.from(this).inflate(, null);
      parent.addView(view, 100, 100);

      // result: layout_height=25dp layout_width=25dp
      // view=textView due to attachRoot=false
      view = LayoutInflater.from(this).inflate(, parent, false);

      // result: layout_height=25dp layout_width=25dp 
      // parent.addView not necessary as this is already done by attachRoot=true
      // view=root due to parent supplied as hierarchy root and attachRoot=true
      view = LayoutInflater.from(this).inflate(, parent, true);

The actual results of the parameter variations are documented in the code.

SYNOPSIS: Calling LayoutInflater without specifying root leads to inflate call ignoring the layout parameters from the XML. Calling inflate with root not equal null and attachRoot=true does load the layout parameters, but returns the root object again, which prevents further layout changes to the loaded object (unless you can find it using findViewById()). The calling convention you most likely would like to use is therefore this one:

loadedView = LayoutInflater.from(context)
                .inflate(R.layout.layout_to_load, parent, false);

To help with layout issues, the Layout Inspector is highly recommended.

Generating a PDF file from React Components

Rendering react as pdf is generally a pain, but there is a way around it using canvas.

The idea is to convert : HTML -> Canvas -> PNG (or JPEG) -> PDF

To achieve the above, you'll need :

  1. html2canvas &
  2. jsPDF

import React, {Component, PropTypes} from 'react';_x000D_
// download html2canvas and jsPDF and save the files in app/ext, or somewhere else_x000D_
// the built versions are directly consumable_x000D_
// import {html2canvas, jsPDF} from 'app/ext';_x000D_
export default class Export extends Component {_x000D_
  constructor(props) {_x000D_
  printDocument() {_x000D_
    const input = document.getElementById('divToPrint');_x000D_
      .then((canvas) => {_x000D_
        const imgData = canvas.toDataURL('image/png');_x000D_
        const pdf = new jsPDF();_x000D_
        pdf.addImage(imgData, 'JPEG', 0, 0);_x000D_
        // pdf.output('dataurlnewwindow');_x000D_"download.pdf");_x000D_
  render() {_x000D_
    return (<div>_x000D_
      <div className="mb5">_x000D_
        <button onClick={this.printDocument}>Print</button>_x000D_
      <div id="divToPrint" className="mt4" {...css({_x000D_
        backgroundColor: '#f5f5f5',_x000D_
        width: '210mm',_x000D_
        minHeight: '297mm',_x000D_
        marginLeft: 'auto',_x000D_
        marginRight: 'auto'_x000D_
        <div>Note: Here the dimensions of div are same as A4</div> _x000D_
        <div>You Can add any component here</div>_x000D_

The snippet will not work here because the required files are not imported.

An alternate approach is being used in this answer, where the middle steps are dropped and you can simply convert from HTML to PDF. There is an option to do this in the jsPDF documentation as well, but from personal observation, I feel that better accuracy is achieved when dom is converted into png first.

Update 0: September 14, 2018

The text on the pdfs created by this approach will not be selectable. If that's a requirement, you might find this article helpful.

invalid types 'int[int]' for array subscript

You are subscripting a three-dimensional array myArray[10][10][10] four times myArray[i][t][x][y]. You will probably need to add another dimension to your array. Also consider a container like Boost.MultiArray, though that's probably over your head at this point.

Pass array to MySQL stored routine

I'm not sure if this is fully answering the question (it isn't), but it's the solution I came up with for my similar problem. Here I try to just use LOCATE() just once per delimiter.

-- *****************************************************************************
-- test_PVreplace


delimiter //
CREATE FUNCTION test_PVreplace (
   str TEXT,   -- String to do search'n'replace on
   pv TEXT     -- Parameter/value pairs 'p1=v1|p2=v2|p3=v3'

-- Replace specific tags with specific values.

   DECLARE idx0 INT DEFAULT 1;   -- 1-origined, not 0-origined

   -- P/V string *must* end with a delimiter.

   IF (RIGHT (pv, 1) <> '|') THEN
      SET pv = CONCAT (pv, '|');
      END IF;

   -- Find all the P/V pairs.

   SELECT LOCATE ('|', pv, idx0) INTO idx;
   WHILE (idx > 0) DO
      SET len = idx - idx0;
      SELECT SUBSTRING(pv, idx0, len) INTO sPV;

      -- Found a P/V pair.  Break it up.

      SELECT LOCATE ('=', sPV) INTO iPV;
      IF (iPV = 0) THEN
         SET sP = sPV;
         SET sV = '';
         SELECT SUBSTRING(sPV, 1, iPV-1) INTO sP;
         END IF;

      -- Do the substitution(s).

      SELECT REPLACE (str, sP, sV) INTO str;

      -- Do next P/V pair.

      SET idx0 = idx + 1;
      SELECT LOCATE ('|', pv, idx0) INTO idx;
      END WHILE;
   RETURN (str);
delimiter ;

SELECT test_PVreplace ('%one% %two% %three%', '%one%=1|%two%=2|%three%=3');
SELECT test_PVreplace ('%one% %two% %three%', '%one%=I|%two%=II|%three%=III');
SELECT test_PVreplace ('%one% %two% %three% - %one% %two% %three%', '%one%=I|%two%=II|%three%=III');
SELECT test_PVreplace ('%one% %two% %three% - %one% %two% %three%', '');
SELECT test_PVreplace ('%one% %two% %three% - %one% %two% %three%', NULL);
SELECT test_PVreplace ('%one% %two% %three%', '%one%=%two%|%two%=%three%|%three%=III');

How to remove an id attribute from a div using jQuery?

I'm not sure what jQuery api you're looking at, but you should only have to specify id.


How can I make a button redirect my page to another page?

Just another variation:

    <button name="redirect" onClick="redirect()">

    <script type="text/javascript">
    function redirect()
    var url = "http://www.(url).com";

How to find MySQL process list and to kill those processes?

select GROUP_CONCAT(stat SEPARATOR ' ') from (select concat('KILL ',id,';') as stat from information_schema.processlist) as stats;

Then copy and paste the result back into the terminal. Something like:

KILL 2871; KILL 2879; KILL 2874; KILL 2872; KILL 2866;

Select mySQL based only on month and year

Suppose you have a database field created_at Where you take value from timestamp. You want to search by Year & Month from created_at date.

YEAR(date(created_at))=2019 AND MONTH(date(created_at))=2

SQL Server: converting UniqueIdentifier to string in a case statement

It is possible to use the convert function here, but 36 characters are enough to hold the unique identifier value:

convert(nvarchar(36), requestID) as requestID

How to embed YouTube videos in PHP?

You have to ask users to store the 11 character code from the youtube video.

For e.g.

The eleven character code is : Ahg6qcgoay4

You then take this code and place it in your database. Then wherever you want to place the youtube video in your page, load the character from the database and put the following code:-

e.g. for Ahg6qcgoay4 it will be :

<object width="425" height="350" data="" type="application/x-shockwave-flash"><param name="src" value="" /></object>

Replacing column values in a pandas DataFrame

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

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

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

What is the difference between printf() and puts() in C?

(This is pointed out in a comment by Zan Lynx, but I think it deserves an aswer - given that the accepted answer doesn't mention it).

The essential difference between puts(mystr); and printf(mystr); is that in the latter the argument is interpreted as a formatting string. The result will be often the same (except for the added newline) if the string doesn't contain any control characters (%) but if you cannot rely on that (if mystr is a variable instead of a literal) you should not use it.

So, it's generally dangerous -and conceptually wrong- to pass a dynamic string as single argument of printf:

  char * myMessage;
  // ... myMessage gets assigned at runtime, unpredictable content
  printf(myMessage);  // <--- WRONG! (what if myMessage contains a '%' char?) 
  puts(myMessage);    // ok
  printf("%s\n",myMessage); // ok, equivalent to the previous, perhaps less efficient

The same applies to fputs vs fprintf (but fputs doesn't add the newline).

Importing a CSV file into a sqlite3 database table using Python

import csv, sqlite3

def _get_col_datatypes(fin):
    dr = csv.DictReader(fin) # comma is default delimiter
    fieldTypes = {}
    for entry in dr:
        feildslLeft = [f for f in dr.fieldnames if f not in fieldTypes.keys()]        
        if not feildslLeft: break # We're done
        for field in feildslLeft:
            data = entry[field]

        # Need data to decide
        if len(data) == 0:

        if data.isdigit():
            fieldTypes[field] = "INTEGER"
            fieldTypes[field] = "TEXT"
    # TODO: Currently there's no support for DATE in sqllite

if len(feildslLeft) > 0:
    raise Exception("Failed to find all the columns data types - Maybe some are empty?")

return fieldTypes

def escapingGenerator(f):
    for line in f:
        yield line.encode("ascii", "xmlcharrefreplace").decode("ascii")

def csvToDb(csvFile,dbFile,tablename, outputToFile = False):

    # TODO: implement output to file

    with open(csvFile,mode='r', encoding="ISO-8859-1") as fin:
        dt = _get_col_datatypes(fin)

        reader = csv.DictReader(fin)

        # Keep the order of the columns name just as in the CSV
        fields = reader.fieldnames
        cols = []

        # Set field and type
        for f in fields:
            cols.append("\"%s\" %s" % (f, dt[f]))

        # Generate create table statement:
        stmt = "create table if not exists \"" + tablename + "\" (%s)" % ",".join(cols)
        con = sqlite3.connect(dbFile)
        cur = con.cursor()

        reader = csv.reader(escapingGenerator(fin))

        # Generate insert statement:
        stmt = "INSERT INTO \"" + tablename + "\" VALUES(%s);" % ','.join('?' * len(cols))

        cur.executemany(stmt, reader)

Address already in use: JVM_Bind java

That error means that the you are trying to create a new ServerSocket on a port already in use by another ServerSocket. So try to make your application closing all sockets and connections you know about and be sure your application is completely terminated. Also check if there is another proces you launched by your program.

mySQL select IN range

You can't, but you can use BETWEEN

SELECT job FROM mytable WHERE id BETWEEN 10 AND 15

Note that BETWEEN is inclusive, and will include items with both id 10 and 15.

If you do not want inclusion, you'll have to fall back to using the > and < operators.

SELECT job FROM mytable WHERE id > 10 AND id < 15

How to force deletion of a python object?

In general, to make sure something happens no matter what, you use

from exceptions import NameError

    f = open(x)
except ErrorType as e:
    pass # handle the error
    except NameError: pass

finally blocks will be run whether or not there is an error in the try block, and whether or not there is an error in any error handling that takes place in except blocks. If you don't handle an exception that is raised, it will still be raised after the finally block is excecuted.

The general way to make sure a file is closed is to use a "context manager".

with open(x) as f:
    # do stuff

This will automatically close f.

For your question #2, bar gets closed on immediately when it's reference count reaches zero, so on del foo if there are no other references.

Objects are NOT created by __init__, they're created by __new__.

When you do foo = Foo() two things are actually happening, first a new object is being created, __new__, then it is being initialized, __init__. So there is no way you could possibly call del foo before both those steps have taken place. However, if there is an error in __init__, __del__ will still be called because the object was actually already created in __new__.

Edit: Corrected when deletion happens if a reference count decreases to zero.

Closure in Java 7

A closure is a block of code that can be referenced (and passed around) with access to the variables of the enclosing scope.

Since Java 1.1, anonymous inner class have provided this facility in a highly verbose manner. They also have a restriction of only being able to use final (and definitely assigned) local variables. (Note, even non-final local variables are in scope, but cannot be used.)

Java SE 8 is intended to have a more concise version of this for single-method interfaces*, called "lambdas". Lambdas have much the same restrictions as anonymous inner classes, although some details vary randomly.

Lambdas are being developed under Project Lambda and JSR 335.

*Originally the design was more flexible allowing Single Abstract Methods (SAM) types. Unfortunately the new design is less flexible, but does attempt to justify allowing implementation within interfaces.

Linux error while loading shared libraries: cannot open shared object file: No such file or directory

I got this error and I think its the same reason of yours

error while loading shared libraries: cannot open shared object 
file: No such file or directory

Try this. Fix permissions on files:

cd /opt/Popcorn (or wherever it is) 
chmod -R 555 * (755 if not ok) 
chown -R root:root *

“sudo su” to get permissions on your filesystem.

Kubernetes how to make Deployment to update image

UPDATE 2019-06-24

Based on the @Jodiug comment if you have a 1.15 version you can use the command:

kubectl rollout restart deployment/demo

Read more on the issue:

Well there is an interesting discussion about this subject on the kubernetes GitHub project. See the issue:

From the solutions described there, I would suggest one of two.


1.Prepare deployment

apiVersion: extensions/v1beta1
kind: Deployment
  name: demo
  replicas: 1
        app: demo
      - name: demo
        imagePullPolicy: Always


sed -ie "s/THIS_STRING_IS_REPLACED_DURING_BUILD/$(date)/g" deployment.yml
kubectl apply -f deployment.yml

Second (one liner):

kubectl patch deployment web -p \
  "{\"spec\":{\"template\":{\"metadata\":{\"labels\":{\"date\":\"`date +'%s'`\"}}}}}"

Of course the imagePullPolicy: Always is required on both cases.


Try this:

select CONVERT(datetime, convert(varchar(10), 20120103))

Visual Studio 2008 Product Key in Registry?

I found the product key for Visual Studio 2008 Professional under a slightly different key:


it was listed without the dashes as stated above.

What is a web service endpoint?

A endpoint is a URL for web service.And Endpoints also is a distributed API.

The Simple Object Access Protocol (SOAP) endpoint is a URL. It identifies the location on the built-in HTTP service where the web services listener listens for incoming requests.


Stop setInterval call in JavaScript

In nodeJS you can you use the "this" special keyword within the setInterval function.

You can use this this keyword to clearInterval, and here is an example:

    function clear() {
       return clear;
, 1000)

When you print the value of this special keyword within the function you outpout a Timeout object Timeout {...}

How to select a radio button by default?

Use the checked attribute.

<input type="radio" name="imgsel"  value="" checked /> 


<input type="radio" name="imgsel"  value="" checked="checked" /> 

How do I schedule jobs in Jenkins?

Try using 0 8 * * *. It should work

What are the most widely used C++ vector/matrix math/linear algebra libraries, and their cost and benefit tradeoffs?

So I'm a pretty critical person, and figure if I'm going to invest in a library, I'd better know what I'm getting myself into. I figure it's better to go heavy on the criticism and light on the flattery when scrutinizing; what's wrong with it has many more implications for the future than what's right. So I'm going to go overboard here a little bit to provide the kind of answer that would have helped me and I hope will help others who may journey down this path. Keep in mind that this is based on what little reviewing/testing I've done with these libs. Oh and I stole some of the positive description from Reed.

I'll mention up top that I went with GMTL despite it's idiosyncrasies because the Eigen2 unsafeness was too big of a downside. But I've recently learned that the next release of Eigen2 will contain defines that will shut off the alignment code, and make it safe. So I may switch over.

Update: I've switched to Eigen3. Despite it's idiosyncrasies, its scope and elegance are too hard to ignore, and the optimizations which make it unsafe can be turned off with a define.


Benefits: LGPL MPL2, Clean, well designed API, fairly easy to use. Seems to be well maintained with a vibrant community. Low memory overhead. High performance. Made for general linear algebra, but good geometric functionality available as well. All header lib, no linking required.

Idiocyncracies/downsides: (Some/all of these can be avoided by some defines that are available in the current development branch Eigen3)

  • Unsafe performance optimizations result in needing careful following of rules. Failure to follow rules causes crashes.
    • you simply cannot safely pass-by-value
    • use of Eigen types as members requires special allocator customization (or you crash)
    • use with stl container types and possibly other templates required special allocation customization (or you will crash)
    • certain compilers need special care to prevent crashes on function calls (GCC windows)


Benefits: LGPL, Fairly Simple API, specifically designed for graphics engines. Includes many primitive types geared towards rendering (such as planes, AABB, quatenrions with multiple interpolation, etc) that aren't in any other packages. Very low memory overhead, quite fast, easy to use. All header based, no linking necessary.


  • API is quirky
    • what might be myVec.x() in another lib is only available via myVec[0] (Readability problem)
      • an array or stl::vector of points may cause you to do something like pointsList[0][0] to access the x component of the first point
    • in a naive attempt at optimization, removed cross(vec,vec) and replaced with makeCross(vec,vec,vec) when compiler eliminates unnecessary temps anyway
    • normal math operations don't return normal types unless you shut off some optimization features e.g.: vec1 - vec2 does not return a normal vector so length( vecA - vecB ) fails even though vecC = vecA - vecB works. You must wrap like: length( Vec( vecA - vecB ) )
    • operations on vectors are provided by external functions rather than members. This may require you to use the scope resolution everywhere since common symbol names may collide
    • you have to do
        length( makeCross( vecA, vecB ) )
        gmtl::length( gmtl::makeCross( vecA, vecB ) )
      where otherwise you might try
        vecA.cross( vecB ).length()
  • not well maintained
    • still claimed as "beta"
    • documentation missing basic info like which headers are needed to use normal functionalty
      • Vec.h does not contain operations for Vectors, VecOps.h contains some, others are in Generate.h for example. cross(vec&,vec&,vec&) in VecOps.h, [make]cross(vec&,vec&) in Generate.h
  • immature/unstable API; still changing.
    • For example "cross" has moved from "VecOps.h" to "Generate.h", and then the name was changed to "makeCross". Documentation examples fail because still refer to old versions of functions that no-longer exist.


Can't tell because they seem to be more interested in the fractal image header of their web page than the content. Looks more like an academic project than a serious software project.

Latest release over 2 years ago.

Apparently no documentation in English though supposedly there is something in French somewhere.

Cant find a trace of a community around the project.


Benefits: Old and mature.


  • old as dinosaurs with really crappy APIs

SQL query to check if a name begins and ends with a vowel

The below one worked for me in MySQL:


Groovy Shell warning "Could not open/create prefs root node ..."

I was able to resolve the problem by manually creating the following registry key:


Objective-C - Remove last character from string

In your controller class, create an action method you will hook the button up to in Interface Builder. Inside that method you can trim your string like this:

if ([string length] > 0) {
    string = [string substringToIndex:[string length] - 1];
} else {
    //no characters to delete... attempting to do so will result in a crash

If you want a fancy way of doing this in just one line of code you could write it as:

string = [string substringToIndex:string.length-(string.length>0)];

*Explanation of fancy one-line code snippet:

If there is a character to delete (i.e. the length of the string is greater than 0)
     (string.length>0) returns 1 thus making the code return:
          string = [string substringToIndex:string.length-1];

If there is NOT a character to delete (i.e. the length of the string is NOT greater than 0)
     (string.length>0) returns 0 thus making the code return:
          string = [string substringToIndex:string.length-0];
     Which prevents crashes.

How can I send an inner <div> to the bottom of its parent <div>?

You may not want absolute positioning because it breaks the reflow: in some circumstances, a better solution is to make the grandparent element display:table; and the parent element display:table-cell;vertical-align:bottom;. After doing this, you should be able to give the the child elements display:inline-block; and they will automagically flow towards the bottom of the parent.

how to destroy bootstrap modal window completely?

My approach would be to use the clone() method of jQuery. It creates a copy of your element, and that's what you want : a copy of your first unaltered modal, that you can replace at your wish : Demo (jsfiddle)

var myBackup = $('#myModal').clone();

// Delegated events because we make a copy, and the copied button does not exist onDomReady
$('body').on('click','#myReset',function() {
    var myClone = myBackup.clone();

The markup I used is the most basic, so you just need to bind on the right elements / events, and you should have your wizard reset.

Be careful to bind with delegated events, or rebind at each reset the inner elements of your modal so that each new modal behave the same way.

How can I export Excel files using JavaScript?

If you can generate the Excel file on the server, that is probably the best way. With Excel you can add formatting and get the output to look better. Several Excel options have already been mentioned. If you have a PHP backend, you might consider phpExcel.

If you are trying to do everything on the client in javascript, I don't think Excel is an option. You could create a CSV file and create a data URL to allow the user to download it.

I created a JSFiddle to demonstrate:

This javascript (assuming you are using jQuery) will take the values out of input boxes in a table and build a CSV formatted string:

var csv = "";
$("table").find("tr").each(function () {
    var sep = "";
    $(this).find("input").each(function () {
        csv += sep + $(this).val();
        sep = ",";
    csv += "\n";

If you wish, you can drop the data into a tag on the page (in my case a tag with an id of "csv"):


You can generate a URL to that text with this code:

window.URL = window.URL || window.webkiURL;
var blob = new Blob([csv]);
var blobURL = window.URL.createObjectURL(blob);

Finally, this will add a link to download that data:

attr("href", blobURL).
attr("download", "data.csv").
text("Download Data").

How to make a transparent HTML button?

<div class="button_style">
This is your button value

background-color: Transparent;
border: none;             /* Your can add different style/properties of button Here*/

what is the size of an enum type data in C++?

This is a C++ interview test question not homework.

Then your interviewer needs to refresh his recollection with how the C++ standard works. And I quote:

For an enumeration whose underlying type is not fixed, the underlying type is an integral type that can represent all the enumerator values defined in the enumeration.

The whole "whose underlying type is not fixed" part is from C++11, but the rest is all standard C++98/03. In short, the sizeof(months_t) is not 4. It is not 2 either. It could be any of those. The standard does not say what size it should be; only that it should be big enough to fit any enumerator.

why the all size is 4 bytes ? not 12 x 4 = 48 bytes ?

Because enums are not variables. The members of an enum are not actual variables; they're just a semi-type-safe form of #define. They're a way of storing a number in a reader-friendly format. The compiler will transform all uses of an enumerator into the actual numerical value.

Enumerators are just another way of talking about a number. january is just shorthand for 0. And how much space does 0 take up? It depends on what you store it in.

Are there constants in JavaScript?

If it is worth mentioning, you can define constants in angular using $provide.constant()

angularApp.constant('YOUR_CONSTANT', 'value');

Could not resolve Spring property placeholder

Your property file location is

This is rather unusual, it means that must be located either at the top level of WEB-INF/classes or at the top-level of one of the jars inside WEB-INF/lib. Usually it's good practice to either use a dedicated folder for properties or keep them close to the context files that use them.

So my suggestion is this: Is your properties file perhaps next to your context file? If so, it's not on the classpath (see this question: Is WEB-INF in the CLASSPATH?).

The classpath: prefix maps to a ClassPathResource, but you probably need a ServletContextResource, and you'll get that from a WebApplicationContext using the syntax without prefix:

<context:property-placeholder location="" />