Programs & Examples On #Subscriber

Schema validation failed with the following errors: Data path ".builders['app-shell']" should have required property 'class'

I got the same error when upgraded angular from 6 to 8.

Simple update angular cli to latest version & node version to 10+.

1) Visit this link to get the latest node version. Angular 8 requires 10+.
2) Execute npm i @angular/cli@latest to update cli.

This is what I have currently

enter image description here

Jquery AJAX: No 'Access-Control-Allow-Origin' header is present on the requested resource

If you are using NodeJs for your server side, just add these to your route and you will be Ok

     res.header("Access-Control-Allow-Origin", "*");
     res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");

Your route will then look somehow like this'/odin', function(req, res, next) {
      res.header("Access-Control-Allow-Origin", "*");
      res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");

    return res.json({Name:, Phone:});

Client side for Ajax call

 var sendingData = {
   name: "Odinfono Emmanuel",
   phone: "1234567890"


        url: '',            
        method: 'POST',
        type: 'json',
        data: sendingData,
        success: function (response) {
        error: function (error) {

You should have something like this in your browser console as response

{ name: "Odinfono Emmanuel", phone: "1234567890"}

Enjoy coding....

Cannot find control with name: formControlName in angular reactive form

I tried to generate a form dynamically because the amount of questions depend on an object and for me the error was fixed when I added ngDefaultControl to my mat-form-field.

    <form [formGroup]="questionsForm">
        <ng-container *ngFor="let question of questions">
            <mat-form-field [formControlName]="" ngDefaultControl>
                <textarea matInput rows="3" required></textarea>
        <button mat-raised-button (click)="sendFeedback()">Submit all questions</button>

In sendFeedback() I get the value from my dynamic form by selecting the formgroup's value as such

  sendFeedbackAsAgent():void {
    if (this.questionsForm.valid) {

Angular2 material dialog has issues - Did you add it to @NgModule.entryComponents?

You need to use entryComponents under @NgModule.

This is for dynamically added components that are added using ViewContainerRef.createComponent(). Adding them to entryComponents tells the offline template compiler to compile them and create factories for them.

The components registered in route configurations are added automatically to entryComponents as well because router-outlet also uses ViewContainerRef.createComponent() to add routed components to the DOM.

So your code will be like

  declarations: [
  entryComponents: [DialogResultExampleDialog]

BehaviorSubject vs Observable?

BehaviorSubject vs Observable : RxJS has observers and observables, Rxjs offers a multiple classes to use with data streams, and one of them is a BehaviorSubject.

Observables : Observables are lazy collections of multiple values over time.

BehaviorSubject:A Subject that requires an initial value and emits its current value to new subscribers.

 // RxJS v6+
import { BehaviorSubject } from 'rxjs';

const subject = new BehaviorSubject(123);

//two new subscribers will get initial value => output: 123, 123

//two subscribers will get new value => output: 456, 456;

//new subscriber will get latest value (456) => output: 456

//all three subscribers will get new value => output: 789, 789, 789;

// output: 123, 123, 456, 456, 456, 789, 789, 789

There is no argument given that corresponds to the required formal parameter - .NET Error

You have a constructor which takes 2 parameters. You should write something like:

new ErrorEventArg(errorMsv, lastQuery)

It's less code and easier to read.


Or, in order for your way to work, you can try writing a default constructor for ErrorEventArg which would have no parameters, like this:

public ErrorEventArg() {}

How to make one Observable sequence wait for another to complete before emitting?

Here's a custom operator written with TypeScript that waits for a signal before emitting results:

export function waitFor<T>(
    signal$: Observable<any>
) {
    return (source$: Observable<T>) =>
        new Observable<T>(observer => {
            // combineLatest emits the first value only when
            // both source and signal emitted at least once
                .subscribe(([v]) =>;

You can use it like this:

   .subscribe(value => ...);

Adding subscribers to a list using Mailchimp's API v3

If it helps anyone, here is what I got working in Python using the Python Requests library instead of CURL.

As explained by @staypuftman above, you will need your API Key and List ID from MailChimp and make sure your API Key suffix and URL prefix (i.e. us5) match.


# To add a single contact to MailChimp (using MailChimp v3.0 API), requires:
#   + MailChimp API Key
#   + MailChimp List Id for specific list
#   + MailChimp API URL for adding a single new contact
# Note: the API URL has a 3/4 character location subdomain at the front of the URL string. 
# It can vary depending on where you are in the world. To determine yours, check the last 
# 3/4 characters of your API key. The API URL location subdomain must match API Key 
# suffix e.g. us5, us13, us19 etc. but in this example, us5.
# (suggest you put the following 3 values in 'settings' or 'secrets' file)
MAILCHIMP_API_KEY = 'your-api-key-here-us5'
MAILCHIMP_LIST_ID = 'your-list-id-here'

    # Create new contact data and convert into JSON as this is what MailChimp expects in the API
    # I've hardcoded some test data but use what you get from your form as appropriate
    new_contact_data_dict = {
        "email_address": "[email protected]",              # 'email_address' is a mandatory field
        "status": "subscribed",                           # 'status' is a mandatory field
        "merge_fields": {                                 # 'merge_fields' are optional:
            "FNAME": "John",                  
            "LNAME": "Smith"
    new_contact_data_json = json.dumps(new_contact_data_dict)

    # Create the new contact using MailChimp API using Python 'Requests' library
    req =
        auth=('user', MAILCHIMP_API_KEY),
        headers={"content-type": "application/json"}

    # debug info if required - .text and .json also list the 'merge_fields' names for use in contact JSON above
    # print req.status_code
    # print req.text
    # print req.json()

    if req.status_code == 200:
        # success - do anything you need to do
        # fail - do anything you need to do - but here is a useful debug message
        mailchimp_fail = 'MailChimp call failed calling this URL: {0}\n' \
                         'Returned this HTTP status code: {1}\n' \
                         'Returned this response text: {2}' \
                         .format(req.url, str(req.status_code), req.text)

JQuery Datatables : Cannot read property 'aDataSort' of undefined

In my case I solved the problem by establishing a valid column number when applying the order property inside the script where you configure the data table.

var table = $('#mytable').DataTable({
     order: [[ 1, "desc" ]],

When do you use map vs flatMap in RxJava?

I just wanted to add that with flatMap, you don't really need to use your own custom Observable inside the function and you can rely on standard factory methods/operators:

Observable.from(jsonFile).flatMap(new Func1<File, Observable<String>>() {
    @Override public Observable<String> call(final File file) {
        try {
            String json = new Gson().toJson(new FileReader(file), Object.class);
            return Observable.just(json);
        } catch (FileNotFoundException ex) {
            return Observable.<String>error(ex);

Generally, you should avoid throwing (Runtime-) exceptions from onXXX methods and callbacks if possible, even though we placed as many safeguards as we could in RxJava.

How to POST the data from a modal form of Bootstrap?

You CAN include a modal within a form. In the Bootstrap documentation it recommends the modal to be a "top level" element, but it still works within a form.

You create a form, and then the modal "save" button will be a button of type="submit" to submit the form from within the modal.

<form asp-action="AddUsersToRole" method="POST" class="mb-3">

    @await Html.PartialAsync("~/Views/Users/_SelectList.cshtml", Model.Users)

    <div class="modal fade" id="role-select-modal" tabindex="-1" role="dialog" aria-labelledby="role-select-modal" aria-hidden="true">
        <div class="modal-dialog" role="document">
            <div class="modal-content">
                <div class="modal-header">
                    <h5 class="modal-title" id="exampleModalLabel">Select a Role</h5>
                <div class="modal-body">
                <div class="modal-footer">
                    <button type="submit" class="btn btn-primary">Add Users to Role</button>
                    <button type="button" class="btn btn-secondary" data-dismiss="modal">Cancel</button>


You can post (or GET) your form data to any URL. By default it is the serving page URL, but you can change it by setting the form action. You do not have to use ajax.

Mozilla documentation on form action


Try this:

INSERT INTO `center_course_fee` (`fk_course_id`,`fk_center_code`,`course_fee`) VALUES ('69', '4920153', '6000') ON DUPLICATE KEY UPDATE `course_fee` = '6000';

Found 'OR 1=1/* sql injection in my newsletter database

'OR 1=1 is an attempt to make a query succeed no matter what
The /* is an attempt to start a multiline comment so the rest of the query is ignored.

An example would be

SELECT userid 
FROM users 
WHERE username = ''OR 1=1/*' 
    AND password = ''
    AND domain = ''

As you can see if you were to populate the username field without escaping the ' no matter what credentials the user passes in the query would return all userids in the system likely granting access to the attacker (possibly admin access if admin is your first user). You will also notice the remainder of the query would be commented out because of the /* including the real '.

The fact that you can see the value in your database means that it was escaped and that particular attack did not succeed. However, you should investigate if any other attempts were made.

java.sql.SQLException: - ORA-01000: maximum open cursors exceeded

This problem mainly happens when you are using connection pooling because when you close connection that connection go back to the connection pool and all cursor associated with that connection never get closed as the connection to database is still open. So one alternative is to decrease the idle connection time of connections in pool, so may whenever connection sits idle in connection for say 10 sec , connection to database will get closed and new connection created to put in pool.

SQL Server Error : String or binary data would be truncated

You're trying to write more data than a specific column can store. Check the sizes of the data you're trying to insert against the sizes of each of the fields.

In this case transaction_status is a varchar(10) and you're trying to store 19 characters to it.

JMS Topic vs Queues

A JMS topic is the type of destination in a 1-to-many model of distribution. The same published message is received by all consuming subscribers. You can also call this the 'broadcast' model. You can think of a topic as the equivalent of a Subject in an Observer design pattern for distributed computing. Some JMS providers efficiently choose to implement this as UDP instead of TCP. For topic's the message delivery is 'fire-and-forget' - if no one listens, the message just disappears. If that's not what you want, you can use 'durable subscriptions'.

A JMS queue is a 1-to-1 destination of messages. The message is received by only one of the consuming receivers (please note: consistently using subscribers for 'topic client's and receivers for queue client's avoids confusion). Messages sent to a queue are stored on disk or memory until someone picks it up or it expires. So queues (and durable subscriptions) need some active storage management, you need to think about slow consumers.

In most environments, I would argue, topics are the better choice because you can always add additional components without having to change the architecture. Added components could be monitoring, logging, analytics, etc. You never know at the beginning of the project what the requirements will be like in 1 year, 5 years, 10 years. Change is inevitable, embrace it :-)

Export to CSV using MVC, C# and jQuery

Simple excel file create in mvc 4

public ActionResult results() { return File(new System.Text.UTF8Encoding().GetBytes("string data"), "application/csv", "filename.csv"); }

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

Assuming you are running on a *nix platform, use cron and the php executable.


There are quite a number of questions asking for "running php without cron" on SO already. Here's one:

Schedule scripts without using CRON

That said, the exec() answer above sounds very promising :)

How to send 100,000 emails weekly?

Short answer: While it's technically possible to send 100k e-mails each week yourself, the simplest, easiest and cheapest solution is to outsource this to one of the companies that specialize in it (I did say "cheapest": there's no limit to the amount of development time (and therefore money) that you can sink into this when trying to DIY).

Long answer: If you decide that you absolutely want to do this yourself, prepare for a world of hurt (after all, this is e-mail/e-fail we're talking about). You'll need:

  • e-mail content that is not spam (otherwise you'll run into additional major roadblocks on every step, even legal repercussions)
  • in addition, your content should be easy to distinguish from spam - that may be a bit hard to do in some cases (I heard that a certain pharmaceutical company had to all but abandon e-mail, as their brand names are quite common in spams)
  • a configurable SMTP server of your own, one which won't buckle when you dump 100k e-mails onto it (your ISP's upstream server won't be sufficient here and you'll make the ISP violently unhappy; we used two dedicated boxes)
  • some mail wrapper (e.g. PhpMailer if PHP's your poison of choice; using PHP's mail() is horrible enough by itself)
  • your own sender function to run in a loop, create the mails and pass them to the wrapper (note that you may run into PHP's memory limits if your app has a memory leak; you may need to recycle the sending process periodically, or even better, decouple the "creating e-mails" and "sending e-mails" altogether)

Surprisingly, that was the easy part. The hard part is actually sending it:

  • some servers will ban you when you send too many mails close together, so you need to shuffle and watch your queue (e.g. send one mail to [email protected], then three to other domains, only then another to [email protected])
  • you need to have correct PTR, SPF, DKIM records
  • handling remote server timeouts, misconfigured DNS records and other network pleasantries
  • handling invalid e-mails (and no, regex is the wrong tool for that)
  • handling unsubscriptions (many legitimate newsletters have been reclassified as spam due to many frustrated users who couldn't unsubscribe in one step and instead chose to "mark as spam" - the spam filters do learn, esp. with large e-mail providers)
  • handling bounces and rejects ("no such mailbox [email protected]","mailbox [email protected] full")
  • handling blacklisting and removal from blacklists (Sure, you're not sending spam. Some recipients won't be so sure - with such large list, it will happen sometimes, no matter what precautions you take. Some people (e.g. your not-so-scrupulous competitors) might even go as far to falsely report your mailings as spam - it does happen. On average, it takes weeks to get yourself removed from a blacklist.)

And to top it off, you'll have to manage the legal part of it (various federal, state, and local laws; and even different tangles of laws once you send outside the U.S. (note: you have no way of finding if [email protected] lives in Southwest Elbonia, the country with world's most draconian antispam laws)).

I'm pretty sure I missed a few heads of this hydra - are you still sure you want to do this yourself? If so, there'll be another wave, this time merely the annoying problems inherent in sending an e-mail. (You see, SMTP is a store-and-forward protocol, which means that your e-mail will be shuffled across many SMTP servers around the Internet, in the hope that the next one is a bit closer to the final recipient. Basically, the e-mail is sent to an SMTP server, which puts it into its forward queue; when time comes, it will forward it further to a different SMTP server, until it reaches the SMTP server for the given domain. This forward could happen immediately, or in a few minutes, or hours, or days, or never.) Thus, you'll see the following issues - most of which could happen en route as well as at the destination:

  • the remote SMTP servers don't want to talk to your SMTP server
  • your mails are getting marked as spam (<blink> is not your friend here, nor is <font color=...>)
  • your mails are delivered days, even weeks late (contrary to popular opinion, SMTP is designed to make a best effort to deliver the message sometime in the future - not to deliver it now)
  • your mails are not delivered at all (already sent from e-mail server on hop #4, not sent yet from server on hop #5, the server that currently holds the message crashes, data is lost)
  • your mails are mangled by some braindead server en route (this one is somewhat solvable with base64 encoding, but then the size goes up and the e-mail looks more suspicious)
  • your mails are delivered and the recipients seem not to want them ("I'm sure I didn't sign up for this, I remember exactly what I did a year ago" (of course you do, sir))
  • users with various versions of Microsoft Outlook and its special handling of Internet mail
  • wizard's apprentice mode (a self-reinforcing positive feedback loop - in other words, automated e-mails as replies to automated e-mails as replies to...; you really don't want to be the one to set this off, as you'd anger half the internet at yourself)

and it'll be your job to troubleshoot and solve this (hint: you can't, mostly). The people who run a legit mass-mailing businesses know that in the end you can't solve it, and that they can't solve it either - and they have the reasons well researched, documented and outlined (maybe even as a Powerpoint presentation - complete with sounds and cool transitions - that your bosses can understand), as they've had to explain this a million times before. Plus, for the problems that are actually solvable, they know very well how to solve them.

If, after all this, you are not discouraged and still want to do this, go right ahead: it's even possible that you'll find a better way to do this. Just know that the road ahead won't be easy - sending e-mail is trivial, getting it delivered is hard.


Maybe try this

Select cust.*

From dbo.Customers cust
Left Join dbo.Subscribers subs on cust.Customer_ID = subs.Customer_ID
Where subs.Customer_Id Is Null

Best Practice to Use HttpClient in Multithreaded Environment

With HttpClient 4.5 you can do this:

CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(new PoolingHttpClientConnectionManager()).build();

Note that this one implements Closeable (for shutting down of the connection manager).

What is the behavior difference between return-path, reply-to and from?

for those who got here because the title of the question:

I use Reply-To: address with webforms. when someone fills out the form, the webpage sends an automatic email to the page's owner. the From: is the automatic mail sender's address, so the owner knows it is from the webform. but the Reply-To: address is the one filled in in the form by the user, so the owner can just hit reply to contact them.

Sending mass email using PHP

First off, using the mail() function that comes with PHP is not an optimal solution. It is easily marked as spammed, and you need to set up header to ensure that you are sending HTML emails correctly. As for whether the code snippet will work, it would, but I doubt you will get HTML code inside it correctly without specifying extra headers

I'll suggest you take a look at SwiftMailer, which has HTML support, support for different mime types and SMTP authentication (which is less likely to mark your mail as spam).

add column to mysql table if it does not exist

Procedure from Jake is very simple and good solution for adding new columns, but with one additional line:


you can add new columns later there, and it will work next time too:

delimiter ;;
create procedure foo ()
    declare continue handler for 1060 begin end;
    alter table atable add subscriber_surname varchar(64);
    alter table atable add subscriber_address varchar(254);
call foo();;

How to open a new window on form submit

I found a solution to this also. This page helped me today so, I am re-posting here too.

/** This is the script that will redraw current screen and submit to paypal. */
echo '<script>'."\n" ;
echo 'function serverNotifySelected()'."\n" ;
echo '{'."\n" ;
echo '\'\', \'PayPalPayment\');'."\n" ;
echo '    document.forms[\'paypal_form\'].submit();'."\n" ;
echo '    document.forms[\'server_responder\'].submit();'."\n" ;
echo '}'."\n" ;
echo '</script>'."\n" ;

/** This form will be opened in a new window called PayPalPayment. */
echo '<form action="" name="paypal_form" method="post" target="PayPalPayment">'."\n" ;
echo '<input type="hidden" name="cmd" value="_s-xclick">'."\n" ;
echo '<input type="hidden" name="custom" value="'.$transaction_start.'">'."\n" ;
echo '<input type="hidden" name="hosted_button_id" value="'.$single_product->hosted_button_id.'">'."\n" ;
echo '<table>'."\n" ;
echo '    <tr>'."\n";
echo '        <td><input type="hidden" name="'.$single_product->hide_name_a.'" value="'.$single_product->hide_value_a.'">Local</td>'."\n" ;
echo '    </tr>'."\n" ;
echo '    <tr>'."\n" ;
echo '        <td>'."\n" ;
echo '        <input type="hidden" name="'.$single_product->hide_name_b.'" value="'.$single_product->hide_value_b.'" />'.$single_product->short_desc.' $'.$adj_price.' USD'."\n" ;
                // <select name="os0">
                //     <option value="1 Day">1 Day $1.55 USD</option>
                //     <option value="All Day">All Day $7.50 USD</option>
                //     <option value="3 Day">3 Day $23.00 USD</option>
                //     <option value="31 Day">31 Day $107.00 USD</option>
                // </select>
echo '        </td>'."\n" ;
echo '    </tr>'."\n" ;
echo '</table>'."\n" ;
echo '<input type="hidden" name="currency_code" value="USD">'."\n" ;
echo '</form>'."\n" ;

/** This form will redraw the current page for approval. */
echo '<form action="ProductApprove.php" name="server_responder" method="post" target="_top">'."\n" ;
echo '<input type="hidden" name="trans" value="'.$transaction_start.'">'."\n" ;
echo '<input type="hidden" name="prod_id" value="'.$this->product_id.'">'."\n" ;
echo '</form>'."\n" ;

/** No form here just an input and a button.  onClick will handle all the forms */
echo '<input type="image" src="" border="0" alt="PayPal - The safer, easier way to pay online!" onclick="serverNotifySelected()">'."\n" ;
echo '<img alt="" border="0" src="" width="1" height="1">'."\n" ;

The above code is the code for one button. You press the button and it will redraw the current screen from purchase to pre-approval. At the same time it opens a new window and hands that new window over to PayPal.

Collection was modified; enumeration operation may not execute

This way should cover a situation of concurrency when the function is called again while is still executing (and items need used only once):

 while (list.Count > 0)
    string Item = list[0];
    // do here what you need to do with item

If the function get called while is still executing items will not reiterate from the first again as they get deleted as soon as they get used. Should not affect performance much for small lists.

How to create User/Database in script for Docker Postgres

EDIT - since Jul 23, 2015

The official postgres docker image will run .sql scripts found in the /docker-entrypoint-initdb.d/ folder.

So all you need is to create the following sql script:



and add it in your Dockerfile:


FROM library/postgres
COPY init.sql /docker-entrypoint-initdb.d/

But since July 8th, 2015, if all you need is to create a user and database, it is easier to just make use to the POSTGRES_USER, POSTGRES_PASSWORD and POSTGRES_DB environment variables:

docker run -e POSTGRES_USER=docker -e POSTGRES_PASSWORD=docker -e POSTGRES_DB=docker library/postgres

or with a Dockerfile:

FROM library/postgres

for images older than Jul 23, 2015

From the documentation of the postgres Docker image, it is said that

[...] it will source any *.sh script found in that directory [/docker-entrypoint-initdb.d] to do further initialization before starting the service

What's important here is "before starting the service". This means your script will be executed before the postgres service would be started, hence the error message "could not connect to database postgres".

After that there is another useful piece of information:

If you need to execute SQL commands as part of your initialization, the use of Postgres single user mode is highly recommended.

Agreed this can be a bit mysterious at the first look. What it says is that your initialization script should start the postgres service in single mode before doing its actions. So you could change your make_db.ksh script as follows and it should get you closer to what you want:

NOTE, this has changed recently in the following commit. This will work with the latest change:

export PGUSER=postgres
psql <<- EOSQL
    CREATE USER docker;

Previously, the use of --single mode was required:

gosu postgres postgres --single <<- EOSQL
    CREATE USER docker;

How to call MVC Action using Jquery AJAX and then submit form in MVC?

Assuming that your button is in a form, you are not preventing the default behaviour of the button click from happening i.e. Your AJAX call is made in addition to the form submission; what you're very likely seeing is one of

  1. the form submission happens faster than the AJAX call returns
  2. the form submission causes the browser to abort the AJAX request and continues with submitting the form.

So you should prevent the default behaviour of the button click

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

    // prevent the default event behaviour    

        url: "/Home/SaveDetailedInfo",
        type: "POST",
        data: JSON.stringify({ 'Options': someData}),
        dataType: "json",
        traditional: true,
        contentType: "application/json; charset=utf-8",
        success: function (data) {

            // perform your save call here

            if (data.status == "Success") {
            } else {
                alert("Error occurs on the Database level!");
        error: function () {
            alert("An error has occured!!!");

How to remove element from array in forEach loop?

I understood that you want to remove from the array using a condition and have another array that has items removed from the array. Is right?

How about this?

var review = ['a', 'b', 'c', 'ab', 'bc'];_x000D_
var filtered = [];_x000D_
for(var i=0; i < review.length;) {_x000D_
  if(review[i].charAt(0) == 'a') {_x000D_
console.log("review", review);_x000D_
console.log("filtered", filtered);

Hope this help...

By the way, I compared 'for-loop' to 'forEach'.

If remove in case a string contains 'f', a result is different.

var review = ["of", "concat", "copyWithin", "entries", "every", "fill", "filter", "find", "findIndex", "flatMap", "flatten", "forEach", "includes", "indexOf", "join", "keys", "lastIndexOf", "map", "pop", "push", "reduce", "reduceRight", "reverse", "shift", "slice", "some", "sort", "splice", "toLocaleString", "toSource", "toString", "unshift", "values"];_x000D_
var filtered = [];_x000D_
for(var i=0; i < review.length;) {_x000D_
  if( review[i].includes('f')) {_x000D_
  }else {_x000D_
console.log("review", review);_x000D_
console.log("filtered", filtered);_x000D_
 * review [  "concat",  "copyWithin",  "entries",  "every",  "includes",  "join",  "keys",  "map",  "pop",  "push",  "reduce",  "reduceRight",  "reverse",  "slice",  "some",  "sort",  "splice",  "toLocaleString",  "toSource",  "toString",  "values"] _x000D_
review = ["of", "concat", "copyWithin", "entries", "every", "fill", "filter", "find", "findIndex", "flatMap", "flatten", "forEach", "includes", "indexOf", "join", "keys", "lastIndexOf", "map", "pop", "push", "reduce", "reduceRight", "reverse", "shift", "slice", "some", "sort", "splice", "toLocaleString", "toSource", "toString", "unshift", "values"];_x000D_
filtered = [];_x000D_
review.forEach(function(item,i, object) {_x000D_
  if( item.includes('f')) {_x000D_
console.log("review", review);_x000D_
console.log("filtered", filtered);_x000D_
 * review [  "concat",  "copyWithin",  "entries",  "every",  "filter",  "findIndex",  "flatten",  "includes",  "join",  "keys",  "map",  "pop",  "push",  "reduce",  "reduceRight",  "reverse",  "slice",  "some",  "sort",  "splice",  "toLocaleString",  "toSource",  "toString",  "values"]_x000D_

And remove by each iteration, also a result is different.

var review = ["of", "concat", "copyWithin", "entries", "every", "fill", "filter", "find", "findIndex", "flatMap", "flatten", "forEach", "includes", "indexOf", "join", "keys", "lastIndexOf", "map", "pop", "push", "reduce", "reduceRight", "reverse", "shift", "slice", "some", "sort", "splice", "toLocaleString", "toSource", "toString", "unshift", "values"];_x000D_
var filtered = [];_x000D_
for(var i=0; i < review.length;) {_x000D_
console.log("review", review);_x000D_
console.log("filtered", filtered);_x000D_
review = ["of", "concat", "copyWithin", "entries", "every", "fill", "filter", "find", "findIndex", "flatMap", "flatten", "forEach", "includes", "indexOf", "join", "keys", "lastIndexOf", "map", "pop", "push", "reduce", "reduceRight", "reverse", "shift", "slice", "some", "sort", "splice", "toLocaleString", "toSource", "toString", "unshift", "values"];_x000D_
filtered = [];_x000D_
review.forEach(function(item,i, object) {_x000D_
console.log("review", review);_x000D_
console.log("filtered", filtered);

How to develop a soft keyboard for Android?

A good place to start is the sample application provided on the developer docs.

  • Guidelines would be to just make it as usable as possible. Take a look at the others available on the market to see what you should be aiming for
  • Yes, services can do most things, including internet; provided you have asked for those permissions
  • You can open activities and do anything you like n those if you run into a problem with doing some things in the keyboard. For example HTC's keyboard has a button to open the settings activity, and another to open a dialog to change languages.

Take a look at other IME's to see what you should be aiming for. Some (like the official one) are open source.

How to search multiple columns in MySQL?

You can use the AND or OR operators, depending on what you want the search to return.

SELECT title FROM pages WHERE my_col LIKE %$param1% AND another_col LIKE %$param2%;

Both clauses have to match for a record to be returned. Alternatively:

SELECT title FROM pages WHERE my_col LIKE %$param1% OR another_col LIKE %$param2%;

If either clause matches then the record will be returned.

For more about what you can do with MySQL SELECT queries, try the documentation.

jquery data selector

At the moment I'm selecting like this:


Which seems to work just fine, but it would be nice if jQuery was able to select by that attribute without the 'data-' prefix.

I haven't tested this with data added to elements via jQuery dynamically, so that could be the downfall of this method.

Trying to SSH into an Amazon Ec2 instance - permission error

Well, looking at your post description I feel there were 2 mistakes done by you:-

  1. Set correct permissions for the private key. Below command should help you to set correct file permision.

    chmod 0600 mykey.pem

  2. Wrong ec2 user you are trying to login.

    Looking at your debug log I think you have spawned an Amazon linux instance. The default user for that instance type is ec2-user . If the instance would have been ubuntu then your default user would have been ubuntu .

    ssh -i privatekey.pem default_ssh_user@server_ip

   For an Amazon Linux AMI, the default user name is ec2-user.

   For a Centos AMI, the default user name is centos.

   For a Debian AMI, the default user name is admin or root.

   For a Fedora AMI, the default user name is ec2-user or fedora.

   For a RHEL AMI, the default user name is ec2-user or root.

   For a SUSE AMI, the default user name is ec2-user or root.

   For an Ubuntu AMI, the default user name is ubuntu.

   Otherwise, if ec2-user and root don't work, check with the AMI provider.


jQuery UI: Datepicker set year range dropdown to 100 years

I wanted to implement the datepicker to select the birthdate and I had troubles changing the yearRange as it doesn't seemed to work with my version (1.5). I updated to the newest jquery-ui datepicker version here:

Then I found out they provide this very helpful on-the-fly tool, so you can config your whole datepicker and see what settings you have to use.

That's how I found out that the option


is the option I was looking for and I didn't find any results searching the web.

So for other users: If you also want to provide the datepicker to change the birthdate, I suggest to use this code options:

    startView: 2,
    maxViewMode: 2,
    daysOfWeekHighlighted: "1,2",
    defaultViewDate: { year: new Date().getFullYear()-20, month: 01, day: 01 }

When opening the datepicker you will start with the view to select the years, 20 years ago relative to the current year.

How to get the last five characters of a string using Substring() in C#?

string input = "OneTwoThree";
(if input.length >5)
string str=input.substring(input.length-5,5);

IIS Config Error - This configuration section cannot be used at this path

Follow the below steps to unlock the handlers at the parent level:

1) In the connections tree(in IIS), go to your server node and then to your website.

2) For the website, in the right window you will see configuration editor under Management.

3) Double click on the configuration editor.

4) In the window that opens, on top you will find a drop down for sections. Choose "system.webServer/handlers" from the drop down.

5) On the right side, there is another drop down. Choose "ApplicationHost.Config "

6) On the right most pane, you will find "Unlock Section" under "Section" heading. Click on that.

7) Once the handlers at the applicationHost is unlocked, your website should run fine.

How to Convert Boolean to String

I'm not a fan of the accepted answer as it converts anything which evaluates to false to "false" no just boolean and vis-versa.

Anyway here's my O.T.T answer, it uses the var_export function.

var_export works with all variable types except resource, I have created a function which will perform a regular cast to string ((string)), a strict cast (var_export) and a type check, depending on the arguments provided..


    function to_string($var, $strict = false, $expectedtype = null){

            return trigger_error(__FUNCTION__ . '() expects at least 1 parameter, 0 given', E_USER_WARNING);
        if($expectedtype !== null  && gettype($var) !== $expectedtype){
            return trigger_error(__FUNCTION__ . '() expects parameter 1 to be ' . $expectedtype .', ' . gettype($var) . ' given', E_USER_WARNING);
            return $var;
        if($strict && !is_resource($var)){
            return var_export($var, true);
        return (string) $var;


    function bool_to_string($var){
        return func_num_args() ? to_string($var, true, 'boolean') : to_string();        


    function object_to_string($var){
        return func_num_args() ? to_string($var, true, 'object') : to_string();        


    function array_to_string($var){
        return func_num_args() ? to_string($var, true, 'array') : to_string();        

Is there a decent wait function in C++?

Lots of people have suggested POSIX sleep, Windows Sleep, Windows system("pause"), C++ cin.get()… there's even a DOS getch() in there, from roughly the late 1920s.

Please don't do any of these.

None of these solutions would pass code review in my team. That means, if you submitted this code for inclusion in our products, your commit would be blocked and you would be told to go and find another solution. (One might argue that things aren't so serious when you're just a hobbyist playing around, but I propose that developing good habits in your pet projects is what will make you a valued professional in a business organisation, and keep you hired.)

Keeping the console window open so you can read the output of your program is not the responsibility of your program! When you add a wait/sleep/block to the end of your program, you are violating the single responsibility principle, creating a massive abstraction leak, and obliterating the re-usability/chainability of your program. It no longer takes input and gives output — it blocks for transient usage reasons. This is very non-good.

Instead, you should configure your environment to keep the prompt open after your program has finished its work. Your Batch script wrapper is a good approach! I can see how it would be annoying to have to keep manually updating, and you can't invoke it from your IDE. You could make the script take the path to the program to execute as a parameter, and configure your IDE to invoke it instead of your program directly.

An interim, quick-start approach would be to change your IDE's run command from cmd.exe <myprogram> or <myprogram>, to cmd.exe /K <myprogram>. The /K switch to cmd.exe makes the prompt stay open after the program at the given path has terminated. This is going to be slightly more annoying than your Batch script solution, because now you have to type exit or click on the red 'X' when you're done reading your program's output, rather than just smacking the space bar.

I assume usage of an IDE, because otherwise you're already invoking from a command prompt, and this would not be a problem in the first place. Furthermore, I assume the use of Windows (based on detail given in the question), but this answer applies to any platform… which is, incidentally, half the point.

Jenkins pipeline how to change to another folder

Use WORKSPACE environment variable to change workspace directory.

If doing using Jenkinsfile, use following code :

    sh "pwd"

Scroll to the top of the page after render in react.js

If all want to do is something simple here is a solution that will work for everybody

add this mini function

        top: 0,
        behavior: "smooth"

call the function as following from the footer of the page

<a className="scroll-to-top rounded" style={{display: "inline"}} onClick={this.scrollTop}>TOP</a>

if you want to add nice styles here is the css

.scroll-to-top {_x000D_
  position: fixed;_x000D_
  right: 1rem;_x000D_
  bottom: 1rem;_x000D_
  display: none;_x000D_
  width: 2.75rem;_x000D_
  height: 2.75rem;_x000D_
  text-align: center;_x000D_
  color: #fff;_x000D_
  background: rgba(90, 92, 105, 0.5);_x000D_
  line-height: 46px;_x000D_

How to replace special characters in a string?

Following the example of the Andrzej Doyle's answer, I think the better solution is to use org.apache.commons.lang3.StringUtils.stripAccents():

package bla.bla.utility;

import org.apache.commons.lang3.StringUtils;

public class UriUtility {
    public static String normalizeUri(String s) {
        String r = StringUtils.stripAccents(s);
        r = r.replace(" ", "_");
        r = r.replaceAll("[^\\.A-Za-z0-9_]", "");
        return r;

What is the height of iPhone's onscreen keyboard?



  1. 5S, SE, 5, 5C (320 × 568) keyboardSize = (0.0, 352.0, 320.0, 216.0) keyboardSize = (0.0, 315.0, 320.0, 253.0)

2.6S,6,7,8:(375 × 667) : keyboardSize = (0.0, 407.0, 375.0, 260.

3.6+,6S+, 7+ , 8+ : (414 × 736) keyboardSize = (0.0, 465.0, 414.0, 271.0)

4.XS, X :(375 X 812) keyboardSize = (0.0, 477.0, 375.0, 335.0)

5.XR,XSMAX((414 x 896) keyboardSize = (0.0, 550.0, 414.0, 346.0)

How to use WebRequest to POST some data and read response?


// Create a request using a URL that can receive a post. 
WebRequest request = WebRequest.Create (" ");
// Set the Method property of the request to POST.
request.Method = "POST";
// Create POST data and convert it to a byte array.
string postData = "This is a test that posts this string to a Web server.";
byte[] byteArray = Encoding.UTF8.GetBytes (postData);
// Set the ContentType property of the WebRequest.
request.ContentType = "application/x-www-form-urlencoded";
// Set the ContentLength property of the WebRequest.
request.ContentLength = byteArray.Length;
// Get the request stream.
Stream dataStream = request.GetRequestStream ();
// Write the data to the request stream.
dataStream.Write (byteArray, 0, byteArray.Length);
// Close the Stream object.
dataStream.Close ();
// Get the response.
WebResponse response = request.GetResponse ();
// Display the status.
Console.WriteLine (((HttpWebResponse)response).StatusDescription);
// Get the stream containing content returned by the server.
dataStream = response.GetResponseStream ();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader (dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd ();
// Display the content.
Console.WriteLine (responseFromServer);
// Clean up the streams.
reader.Close ();
dataStream.Close ();
response.Close ();

Take into account that the information must be sent in the format key1=value1&key2=value2

Call a python function from jinja2

If you are doing it with Django, you can just pass the function with the context:

context = {
    'title':'My title',
    'str': str,
return render(request, 'index.html', context)

Now you will be able to use the str function in jinja2 template

Declare a variable in DB2 SQL

I'm coming from a SQL Server background also and spent the past 2 weeks figuring out how to run scripts like this in IBM Data Studio. Hope it helps.

CREATE VARIABLE v_lookupid INTEGER DEFAULT (4815162342); --where 4815162342 is your variable data 
DROP VARIABLE v_lookupid; 

Android Endless List

I've been working in another solution very similar to that, but, I am using a footerView to give the possibility to the user download more elements clicking the footerView, I am using a "menu" which is shown above the ListView and in the bottom of the parent view, this "menu" hides the bottom of the ListView, so, when the listView is scrolling the menu disappear and when scroll state is idle, the menu appear again, but when the user scrolls to the end of the listView, I "ask" to know if the footerView is shown in that case, the menu doesn't appear and the user can see the footerView to load more content. Here the code:


listView.setOnScrollListener(new OnScrollListener() {

    public void onScrollStateChanged(AbsListView view, int scrollState) {
        // TODO Auto-generated method stub
        if(scrollState == SCROLL_STATE_IDLE) {
            if(footerView.isShown()) {
            } else {
            } else {

    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) {


Click event doesn't work on dynamically generated elements

Also you can use onclick="do_something(this)"inside element

PHP and MySQL Select a Single Value

mysql_* extension has been deprecated in 2013 and removed completely from PHP in 2018. You have two alternatives PDO or MySQLi.


The simpler option is PDO which has a neat helper function fetchColumn():

$stmt = $pdo->prepare("SELECT id FROM Users WHERE username=?");
$stmt->execute([ $_GET["username"] ]);
$value = $stmt->fetchColumn();

Proper PDO tutorial


You can do the same with MySQLi, but it is more complicated:

$stmt = $mysqliConn->prepare('SELECT id FROM Users WHERE username=?');
$stmt->bind_param("s", $_GET["username"]);
$data = $stmt->get_result()->fetch_assoc();
$value = $data ? $data['id'] : null;

fetch_assoc() could return NULL if there are no rows returned from the DB, which is why I check with ternary if there was any data returned.

How to create a jQuery function (a new jQuery method or plugin)?

You can write your own jQuery plugins(function which can be called on selected elements) like below:

(function( $ ){
    $.fn.myFunc = function(param1, param2){
        //this - jquery object holds your selected elements
})( jQuery );

Call it later like:

$('div').myFunc(1, null);

RSpec: how to test if a method was called?

The below should work

describe "#foo"
  it "should call 'bar' with appropriate arguments" do
     expect(subject).to have_received(:bar).with("Invalid number of arguments")


Adding a HTTP header to the Angular HttpClient doesn't send the header, why?

I was with Angular 8 and the only thing which worked for me was this:

  getCustomHeaders(): HttpHeaders {
    const headers = new HttpHeaders()
      .set('Content-Type', 'application/json')
      .set('Api-Key', 'xxx');
    return headers;

Node Version Manager install - nvm command not found

Check your .bash_profile, .zshrc, or .profile file. You most likely had a problem during the installation.

You should have the following at the end of one of those files.

[[ -s $HOME/.nvm/ ]] && . $HOME/.nvm/  # This loads NVM

The . $HOME/.nvm/ is the same as source $HOME/.nvm/

See: Sourcing a File

You can also check to see if you have a .nvm folder.

ls -a | grep .nvm

If you're missing that folder then the installation failed to run the git command. This could be due to being behind a proxy. Try running the following instead.

git clone .nvm

Public free web services for testing soap client

There is a bunch on here:

Just google for "Free WebService" or "Open WebService" and you'll find tons of open SOAP endpoints.

Remember, you can get a WSDL from any ASMX endpoint by adding ?WSDL to the url.

T-SQL: Selecting rows to delete via joins

you can run this query:-

Delete from TableA 
TableA a, TableB b 
where a.Bid=b.Bid
AND [my filter condition]

Why use Redux over Facebook Flux?

I'm an early adopter and implemented a mid-large single page application using the Facebook Flux library.

As I'm a little late to the conversation I'll just point out that despite my best hopes Facebook seem to consider their Flux implementation to be a proof of concept and it has never received the attention it deserves.

I'd encourage you to play with it, as it exposes more of the inner working of the Flux architecture which is quite educational, but at the same time it does not provide many of the benefits that libraries like Redux provide (which aren't that important for small projects, but become very valuable for bigger ones).

We have decided that moving forward we will be moving to Redux and I suggest you do the same ;)

Check if string ends with one of the strings from a list

another way which can return the list of matching strings is

sample = "alexis has the control"
matched_strings = filter(sample.endswith, ["trol", "ol", "troll"])
print matched_strings
['trol', 'ol']

How can I profile C++ code running on Linux?

I assume you're using GCC. The standard solution would be to profile with gprof.

Be sure to add -pg to compilation before profiling:

cc -o myprog myprog.c utils.c -g -pg

I haven't tried it yet but I've heard good things about google-perftools. It is definitely worth a try.

Related question here.

A few other buzzwords if gprof does not do the job for you: Valgrind, Intel VTune, Sun DTrace.

How to use: while not in

In your case, ('AND' and 'OR' and 'NOT') evaluates to "NOT", which may or may not be in your list...

while 'AND' not in MyList and 'OR' not in MyList and 'NOT' not in MyList:
    print 'No Boolean Operator'

Is it wrong to place the <script> tag after the </body> tag?

Yes. But if you do add the code outside it most likely will not be the end of the world since most browsers will fix it, but it is still a bad practice to get into.

What are some alternatives to ReSharper?

A comprehensive list:

  • CodeRush, by DevExpress. (Considered the main alternative) Either this or ReSharper is the way to go. You cannot go wrong with either. Both have their fans, both are powerful, both have talented teams constantly improving them. We have all benefited from the competition between these two. I won't repeat the many good discussions/comparisons about them that can be found on Stack Overflow and elsewhere. 1

  • JustCode, by Telerik. This is new, still with kinks, but initial reports are positive. An advantage could be liscensing with other Telerik products and integration with them. 1

  • Many of the new Visual Studio 2010 features. See what's been added vs. what you need, it could be that the core install takes care of what you are interested in now.

  • Visual Assist X, More than 50 features make Visual Assist X an incredible productivity tool. Pick a category and learn more, or download a free trial and discover them all. 2

  • VSCommands, VSCommands provides code navigation and generation improvements which will make your everyday coding tasks blazing fast and, together with tens of essential IDE enhancements, it will take your productivity to another level. VSCommands comes in two flavours: Lite (free) and Pro (paid). 3

  • BrockSoft VSAid, VSAid (Visual Studio Aid) is a Microsoft Visual Studio add-in available, at no cost, for both personal and commercial use. Primarily aimed at Visual C++ developers (though useful for any Visual Studio project or solution), VSAid adds a new toolbar to the IDE which adds productivity-enhancing features such as being able to find and open project files quickly and cycle through related files at the click of a mouse button (or the stroke of a key!). 4

Should I use 'has_key()' or 'in' on Python dicts?

has_key is a dictionary method, but in will work on any collection, and even when __contains__ is missing, in will use any other method to iterate the collection to find out.

Why is using "" for array iteration a bad idea?

Because it will iterate over properties belonging to objects up the prototype chain if you're not careful.

You can use for.. in, just be sure to check each property with hasOwnProperty.

Javascript - How to detect if document has loaded (IE 7/Firefox 3)

Mozila Firefox says that onreadystatechange is an alternative to DOMContentLoaded.

// alternative to DOMContentLoaded
document.onreadystatechange = function () {
    if (document.readyState == "complete") {

In DOMContentLoaded the Mozila's doc says:

The DOMContentLoaded event is fired when the document has been completely loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading (the load event can be used to detect a fully-loaded page).

I think load event should be used for a full document+resources loading.

How to include PHP files that require an absolute path?

This should work

$root = realpath($_SERVER["DOCUMENT_ROOT"]);

include "$root/inc/include1.php";

Edit: added imporvement by aussieviking

Could not create work tree dir ''.: Permission denied

Tested On Ubuntu 20, sudo chown -R $USER:$USER /var/www

How do I add to the Windows PATH variable using setx? Having weird problems

This works perfectly:

for /f "usebackq tokens=2,*" %A in (`reg query HKCU\Environment /v PATH`) do set my_user_path=%B

setx PATH "C:\Python27;C:\Python27\Scripts;%my_user_path%"

The 1st command gets the USER environment variable 'PATH', into 'my_user_path' variable The 2nd line prepends the 'C:\Python27;C:\Python27\Scripts;' to the USER environment variable 'PATH'

Python string class like StringBuilder in C#?

I have used the code of Oliver Crow (link given by Andrew Hare) and adapted it a bit to tailor Python 2.7.3. (by using timeit package). I ran on my personal computer, Lenovo T61, 6GB RAM, Debian GNU/Linux 6.0.6 (squeeze).

Here is the result for 10,000 iterations:

method1:  0.0538418292999 secs
process size 4800 kb
method2:  0.22602891922 secs
process size 4960 kb
method3:  0.0605459213257 secs
process size 4980 kb
method4:  0.0544030666351 secs
process size 5536 kb
method5:  0.0551080703735 secs
process size 5272 kb
method6:  0.0542731285095 secs
process size 5512 kb

and for 5,000,000 iterations (method 2 was ignored because it ran tooo slowly, like forever):

method1:  5.88603997231 secs
process size 37976 kb
method3:  8.40748500824 secs
process size 38024 kb
method4:  7.96380496025 secs
process size 321968 kb
method5:  8.03666186333 secs
process size 71720 kb
method6:  6.68192911148 secs
process size 38240 kb

It is quite obvious that Python guys have done pretty great job to optimize string concatenation, and as Hoare said: "premature optimization is the root of all evil" :-)

Changing :hover to touch/click for mobile devices

I am a CSS noob but I have noticed that hover will work for touch screens so long as it's a "hoverable" element: image, link, button. You can do it all with CSS using the following trick.

Change your div background to an actual image tag within the div or create a dummy link around the entire div, it will then register as a hover when you touch the image.

Doing this will mean that you need the rest of your page to also be "hoverable" so when you touch outside of the image it recognizes that info-slide:hover has ended. My trick is to make all of my other content dummy links.

It's not very elegant but it works.

How to handle a single quote in Oracle SQL

I found the above answer giving an error with Oracle SQL, you also must use square brackets, below;

SQL> SELECT Q'[Paddy O'Reilly]' FROM DUAL;

Result: Paddy O'Reilly

Razor If/Else conditional operator syntax

You need to put the entire ternary expression in parenthesis. Unfortunately that means you can't use "@:", but you could do something like this:

@(deletedView ? "Deleted" : "Created by")

Razor currently supports a subset of C# expressions without using @() and unfortunately, ternary operators are not part of that set.

Difference between using gradlew and gradle

gradlew is a wrapper(w - character) that uses gradle.

Under the hood gradlew performs three main things:

  • Download and install the correct gradle version
  • Parse the arguments
  • Call a gradle task

Using Gradle Wrapper we can distribute/share a project to everybody to use the same version and Gradle's functionality(compile, build, install...) even if it has not been installed.

To create a wrapper run:

gradle wrapper

This command generate: will contain the information about the Gradle distribution

*./ Is used on Unix to specify the current directory

How to comment out particular lines in a shell script

for single line comment add # at starting of a line
for multiple line comments add ' (single quote) from where you want to start & add ' (again single quote) at the point where you want to end the comment line.

Why when a constructor is annotated with @JsonCreator, its arguments must be annotated with @JsonProperty?

It is possible to avoid constructor annotations with jdk8 where optionally the compiler will introduce metadata with the names of the constructor parameters. Then with jackson-module-parameter-names module Jackson can use this constructor. You can see an example at post Jackson without annotations

Java8: HashMap<X, Y> to HashMap<X, Z> using Stream / Map-Reduce / Collector

A generic solution like so

public static <X, Y, Z> Map<X, Z> transform(Map<X, Y> input,
        Function<Y, Z> function) {
    return input
                    Collectors.toMap((entry) -> entry.getKey(),
                            (entry) -> function.apply(entry.getValue())));


Map<String, String> input = new HashMap<String, String>();
input.put("string1", "42");
input.put("string2", "41");
Map<String, Integer> output = transform(input,
            (val) -> Integer.parseInt(val));

How to round a floating point number up to a certain decimal place?

Here is a simple function to do this for you:

def precision(num,x):
    return "{0:.xf}".format(round(num))

Here, num is the decimal number. x is the decimal up to where you want to round a floating number.

The advantage over other implementation is that it can fill zeros at the right end of the decimal to make a deciaml number up to x decimal places.

Example 1:

precision(10.2, 9)

will return

10.200000000 (up to 9 decimal points)

Example 2:

precision(10.2231, 2)

will return

10.22 (up to two decimal points)

How to get the selected item of a combo box to a string variable in c#

SelectedText = this.combobox.SelectionBoxItem.ToString();

Oracle to_date, from mm/dd/yyyy to dd-mm-yyyy

You don't need to muck about with extracting parts of the date. Just cast it to a date using to_date and the format in which its stored, then cast that date to a char in the format you want. Like this:

select to_char(to_date('1/10/2011','mm/dd/yyyy'),'mm-dd-yyyy') from dual

JWT refresh token flow

Based in this implementation with Node.js of JWT with refresh token:

1) In this case they use a uid and it's not a JWT. When they refresh the token they send the refresh token and the user. If you implement it as a JWT, you don't need to send the user, because it would inside the JWT.

2) They implement this in a separated document (table). It has sense to me because a user can be logged in in different client applications and it could have a refresh token by app. If the user lose a device with one app installed, the refresh token of that device could be invalidated without affecting the other logged in devices.

3) In this implementation it response to the log in method with both, access token and refresh token. It seams correct to me.

Add hover text without javascript like we hover on a user's reputation

This can also be done in CSS, for more customisability:

.hoverable {
  position: relative;

.hoverable>.hoverable__tooltip {
  display: none;

.hoverable:hover>.hoverable__tooltip {
  display: inline;
  position: absolute;
  top: 1em;
  left: 1em;
  background: #888;
  border: 1px solid black;
<div class="hoverable">
  <span class="hoverable__main">Main text</span>
  <span class="hoverable__tooltip">Hover text</span>

(Obviously, styling can be improved)

How to display the string html contents into webbrowser control?

Try this:

webBrowser1.DocumentText =
    "<html><body>Please enter your name:<br/>" +
    "<input type='text' name='userName'/><br/>" +
    "<a href=''>continue</a>" +

How do I include a path to libraries in g++

To specify a directory to search for (binary) libraries, you just use -L:


To specify the actual library name, you use -l:

-lfoo  # (links libfoo.a or

To specify a directory to search for include files (different from libraries!) you use -I:


So I think what you want is something like

g++ -g -Wall -I/data[...]/lib testing.cpp fileparameters.cpp main.cpp -o test

These compiler flags (amongst others) can also be found at the GNU GCC Command Options manual:

How to add headers to a multicolumn listbox in an Excel userform using VBA

There is very easy solution to show headers at the top of multi columns list box. Just change the property value to "true" for "columnheads" which is false by default.

After that Just mention the data range in property "rowsource" excluding header from the data range and header should be at first top row of data range then it will pick the header automatically and you header will be freezed.

if suppose you have data in range "A1:H100" and header at "A1:H1" which is the first row then your data range should be "A2:H100" which needs to mention in property "rowsource" and "columnheads" perperty value should be true

Regards, Asif Hameed

C++, copy set to vector

set<T> s;
vector<T> v;
v.assign(s.begin(), s.end());

How do I get the application exit code from a Windows command line?

A pseudo environment variable named errorlevel stores the exit code:

echo Exit Code is %errorlevel%

Also, the if command has a special syntax:

if errorlevel

See if /? for details.


@echo off
if errorlevel 1 (
   echo Failure Reason Given is %errorlevel%
   exit /b %errorlevel%

Warning: If you set an environment variable name errorlevel, %errorlevel% will return that value and not the exit code. Use (set errorlevel=) to clear the environment variable, allowing access to the true value of errorlevel via the %errorlevel% environment variable.

UIButton action in table view cell

The accepted answer is good and simple approach but have limitation of information it can hold with tag. As sometime more information needed.

You can create a custom button and add properties as many as you like they will hold info you wanna pass:

class CustomButton: UIButton {
    var orderNo = -1
    var clientCreatedDate = Date(timeIntervalSince1970: 1)

Make button of this type in Storyboard or programmatically:

protocol OrderStatusDelegate: class {
    func orderStatusUpdated(orderNo: Int, createdDate: Date)

class OrdersCell: UITableViewCell {
    @IBOutlet weak var btnBottom: CustomButton!
    weak var delegate: OrderStatusDelegate?

While configuring the cell add values to these properties:

 func configureCell(order: OrderRealm, index: Int) {
     btnBottom.orderNo = Int(order.orderNo)
     btnBottom.clientCreatedDate = order.clientCreatedDate

When tapped access those properties in button's action (within cell's subclass) that can be sent through delegate:

@IBAction func btnBumpTapped(_ sender: Any) {
    if let button = sender as? CustomButton {
        let orderNo = button.orderNo
        let createdDate = button.clientCreatedDate
        delegate?.orderStatusUpdated(orderNo: orderNo, createdDate: createdDate)

What are the use cases for selecting CHAR over VARCHAR in SQL?

In some SQL databases, VARCHAR will be padded out to its maximum size in order to optimize the offsets, This is to speed up full table scans and indexes.

Because of this, you do not have any space savings by using a VARCHAR(200) compared to a CHAR(200)

How to convert dd/mm/yyyy string into JavaScript Date object?

You can use toLocaleString(). This is a javascript method.

var event = new Date("01/02/1993");_x000D_
var options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };_x000D_
console.log(event.toLocaleString('en', options));_x000D_
// expected output: "Saturday, January 2, 1993"

Almost all formats supported. Have look on this link for more details.

String Concatenation in EL

With EL 2 you can do the following:

#{'this'.concat(' is').concat(' a').concat(' test!')}

How do I find all files containing specific text on Linux?

grep can be used even if we're not looking for a string.

Simply running,

grep -RIl "" .

will print out the path to all text files, i.e. those containing only printable characters.

Adding a splash screen to Flutter apps

The code from Jaldhi Bhatt doesn't works for me.

Flutter throws a 'Navigator operation requested with a context that does not include a Navigator.'

I fixed the code wrapping the Navigator consumer component inside of another component that initialize the Navigator context using routes, as mentioned in this article.

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:my-app/view/main-view.dart';

class SplashView extends StatelessWidget {

  Widget build(BuildContext context) {
    return new MaterialApp(
        home: Builder(
          builder: (context) => new _SplashContent(),
        routes: <String, WidgetBuilder>{
          '/main': (BuildContext context) => new MainView()}

class _SplashContent extends StatefulWidget{

  _SplashContentState createState() => new _SplashContentState();

class _SplashContentState extends State<_SplashContent>
    with SingleTickerProviderStateMixin {

  var _iconAnimationController;
  var _iconAnimation;

  startTimeout() async {
    var duration = const Duration(seconds: 3);
    return new Timer(duration, handleTimeout);

  void handleTimeout() {
    Navigator.pushReplacementNamed(context, "/main");

  void initState() {

    _iconAnimationController = new AnimationController(
        vsync: this, duration: new Duration(milliseconds: 2000));

    _iconAnimation = new CurvedAnimation(
        parent: _iconAnimationController, curve: Curves.easeIn);
    _iconAnimation.addListener(() => this.setState(() {}));



  Widget build(BuildContext context) {
    return new Center(
        child: new Image(
          image: new AssetImage("images/logo.png"),
          width: _iconAnimation.value * 100,
          height: _iconAnimation.value * 100,

Loading a .json file into c# program

As mentioned in the other answer I would recommend using json.NET. You can download the package using NuGet. Then to deserialize your json files into C# objects you can do something like;

   JsonSerializer serializer = new JsonSerializer();
   MyObject obj = serializer.Deserialize<MyObject>(File.ReadAllText(@".\path\to\json\config\file.json");

The above code assumes that you have something like

public class MyObject
    public string prop1 { get; set; };
    public string prop2 { get; set; };

And your json looks like;


I prefer using the generic deserialize method which will deserialize json into an object assuming that you provide it with a type who's definition matches the json's. If there are discrepancies between the two it could throw, or not set values, or just ignore things in the json, depends on what the problem is. If the json definition exactly matches the C# types definition then it just works.

Setting UILabel text to bold

Use font property of UILabel:

label.font = UIFont(name:"HelveticaNeue-Bold", size: 16.0)

or use default system font to bold text:

label.font = UIFont.boldSystemFont(ofSize: 16.0)

Android "hello world" pushnotification example

Update 2016:

GCM is being replaced with FCM

Update 2015:

Have a look at - Google replaced C2DM with GCM Demo Implementation / How To

Update 2014:

1) You need to check on the server what HTTP response you are getting from the Google servers. Make sure it is a 200 OK response, so you know the message was sent. If you get another response (302, etc) then the message is not being sent successfully.

2) You also need to check that the Registration ID you are using is correct. If you provide the wrong Registration ID (as a destination for the message - specifying the app, on a specific device) then the Google servers cannot successfully send it.

3) You also need to check that your app is successfully registering with the Google servers, to receive push notifications. If the registration fails, you will not receive messages.

First Answer 2014

Here is a good question you may should have a look at it: How to add a push notification in my own android app

Also here is a good blog with a really simple how to:

CSS: How can I set image size relative to parent height?

Use max-width property of CSS, like this :


What is the iOS 6 user agent string?


Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25


Mozilla/5.0 (iPad; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25

For a complete list and more details about the iOS user agent check out these 2 resources:
Safari User Agent Strings (
Complete List of iOS User-Agent Strings (

Java - Opposite of .contains (does not contain)


if (inventory.contains("bread") && !inventory.contains("water"))


if (inventory.contains("bread")) {
    if (!inventory.contains("water")) {
        // do something here

How to implement WiX installer upgrade?

I'm using the latest version of WiX (3.0) and couldn't get the above working. But this did work:

<Product Id="*" UpgradeCode="PUT-GUID-HERE" ... >

<Upgrade Id="PUT-GUID-HERE">
  <UpgradeVersion OnlyDetect="no" Property="PREVIOUSFOUND"
     Minimum=""  IncludeMinimum="yes"
     Maximum="" IncludeMaximum="no" />

Note that PUT-GUID-HERE should be the same as the GUID that you have defined in the UpgradeCode property of the Product.

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

One of the main benefits of using streams is that it gives the ability to process data in a declarative way, that is, using a functional style of programming. It also gives multi-threading capability for free meaning there is no need to write any extra multi-threaded code to make your stream concurrent.

Assuming the reason you are exploring this style of programming is that you want to exploit these benefits then your first code sample is potentially not functional since the foreach method is classed as being terminal (meaning that it can produce side-effects).

The second way is preferred from functional programming point of view since the map function can accept stateless lambda functions. More explicitly, the lambda passed to the map function should be

  1. Non-interfering, meaning that the function should not alter the source of the stream if it is non-concurrent (e.g. ArrayList).
  2. Stateless to avoid unexpected results when doing parallel processing (caused by thread scheduling differences).

Another benefit with the second approach is if the stream is parallel and the collector is concurrent and unordered then these characteristics can provide useful hints to the reduction operation to do the collecting concurrently.

open_basedir restriction in effect. File(/) is not within the allowed path(s):

If used ispconfig3:

Go to Website section -> Options -> PHP open_basedir:

enter image description here

  • In this field has described allowed paths and each path is separated with ":"

/var/www/clients/client2/web3/image:/var/www/clients/client2/web3/web:/var/www/... and so on

  • So here must put the path that you want to have access, in my case is:


  • The problem appears because:

When a script tries to access the filesystem, for example using include, or fopen(), the location of the file is checked. When the file is outside the specified directory-tree, PHP will refuse to access it.

Render a string in HTML and preserve spaces and linebreaks

I was trying the white-space: pre-wrap; technique stated by pete but if the string was continuous and long it just ran out of the container, and didn't warp for whatever reason, didn't have much time to investigate.. but if you too are having the same problem, I ended up using the <pre> tags and the following css and everything was good to go..

pre {
font-size: inherit;
color: inherit;
border: initial;
padding: initial;
font-family: inherit;

How can I represent an 'Enum' in Python?

On 2013-05-10, Guido agreed to accept PEP 435 into the Python 3.4 standard library. This means that Python finally has builtin support for enumerations!

There is a backport available for Python 3.3, 3.2, 3.1, 2.7, 2.6, 2.5, and 2.4. It's on Pypi as enum34.


>>> from enum import Enum
>>> class Color(Enum):
...     red = 1
...     green = 2
...     blue = 3


>>> print(
>>> print(repr(
< 1>


>>> for color in Color:
...   print(color)

Programmatic access:

>>> Color(1)
>>> Color['blue']

For more information, refer to the proposal. Official documentation will probably follow soon.

How to connect to Mysql Server inside VirtualBox Vagrant?

This worked for me: Connect to MySQL in Vagrant

username: vagrant password: vagrant

sudo apt-get update sudo apt-get install build-essential zlib1g-dev
git-core sqlite3 libsqlite3-dev sudo aptitude install mysql-server

sudo nano /etc/mysql/my.cnf change: bind-address            =

mysql -u root -p

use mysql GRANT ALL ON *.* to root@'' IDENTIFIED BY
'jarvis'; FLUSH PRIVILEGES; exit

sudo /etc/init.d/mysql restart

# -*- mode: ruby -*-
# vi: set ft=ruby : do |config| = "lucid32"

  config.vm.box_url = ""

  #config.vm.boot_mode = :gui

  # Assign this VM to a host-only network IP, allowing you to access
it   # via the IP. Host-only networks can talk to the host machine as
well as   # any other machines on the same network, but cannot be
accessed (through this   # network interface) by any external
networks.   # :hostonly, ""

  # Assign this VM to a bridged network, allowing you to connect
directly to a   # network using the host's network device. This makes
the VM appear as another   # physical device on your network.   # :bridged

  # Forward a port from the guest to the host, which allows for
outside   # computers to access the VM, whereas host only networking
does not.   # config.vm.forward_port 80, 8080

  config.vm.forward_port 3306, 3306 :hostonly, ""


Why is SQL server throwing this error: Cannot insert the value NULL into column 'id'?

As id is PK it MUST be unique and not null. If you do not mention any field in the fields list for insert it'll be supposed to be null or default value. Set identity (i.e. autoincrement) for this field if you do not want to set it manualy every time.

How do I concatenate two lists in Python?

This is quite simple, and I think it was even shown in the tutorial:

>>> listone = [1,2,3]
>>> listtwo = [4,5,6]
>>> listone + listtwo
[1, 2, 3, 4, 5, 6]

How to SSH into Docker?

It is a short way but not permanent

first create a container

docker run  ..... -p 22022:2222 .....

port 22022 on your host machine will map on 2222, we change the ssh port on container later , then on your container executing the following commands

apt update && apt install  openssh-server # install ssh server
passwd #change root password

in file /etc/ssh/sshd_config change these : uncomment Port and change it to 2222

Port 2222

uncomment PermitRootLogin to

PermitRootLogin yes

and finally restart ssh server

/etc/init.d/ssh start

you can login to your container now

ssh -p 2022 root@HostIP

Remember : if you restart the container you need to restart ssh server again

How to check if a variable exists in a FreeMarker template?

I think a lot of people are wanting to be able to check to see if their variable is not empty as well as if it exists. I think that checking for existence and emptiness is a good idea in a lot of cases, and makes your template more robust and less prone to silly errors. In other words, if you check to make sure your variable is not null AND not empty before using it, then your template becomes more flexible, because you can throw either a null variable or an empty string into it, and it will work the same in either case.

<#if p?? && p?has_content>1</#if>

Let's say you want to make sure that p is more than just whitespace. Then you could trim it before checking to see if it has_content.

<#if p?? && p?trim?has_content>1</#if>


Please ignore my suggestion -- has_content is all that is needed, as it does a null check along with the empty check. Doing p?? && p?has_content is equivalent to p?has_content, so you may as well just use has_content.

How to calculate UILabel width based on text length?

CGSize expectedLabelSize = [yourString sizeWithFont:yourLabel.font 

What is -[NSString sizeWithFont:forWidth:lineBreakMode:] good for?

this question might have your answer, it worked for me.

For 2014, I edited in this new version, based on the ultra-handy comment by Norbert below! This does everything. Cheers

// yourLabel is your UILabel.

float widthIs = 
  attributes:@{ NSFontAttributeName:self.yourLabel.font }

NSLog(@"the width of yourLabel is %f", widthIs);

Show a child form in the centre of Parent form in C#

There seems to be a confusion between "Parent" and "Owner". If you open a form as MDI-form, i.e. imbedded inside another form, then this surrounding form is the Parent. The form property StartPosition with the value FormStartPosition.CenterParent refers to this one. The parameter you may pass to the Show method is the Owner, not the Parent! This is why frm.StartPosition = FormStartPosition.CenterParent does not work as you may expect.

The following code placed in a form will center it with respect to its owner with some offset, if its StartPosition is set to Manual. The small offset opens the forms in a tiled manner. This is an advantage if the owner and the owned form have the same size or if you open several owned forms.

protected override void OnShown(EventArgs e)
    if (Owner != null && StartPosition == FormStartPosition.Manual) {
        int offset = Owner.OwnedForms.Length * 38;  // approx. 10mm
        Point p = new Point(Owner.Left + Owner.Width / 2 - Width / 2 + offset, Owner.Top + Owner.Height / 2 - Height / 2 + offset);
        this.Location = p;

How to filter empty or NULL names in a QuerySet?

You could do this:


If you need to exclude null values and empty strings, the preferred way to do so is to chain together the conditions like so:


Chaining these methods together basically checks each condition independently: in the above example, we exclude rows where alias is either null or an empty string, so you get all Name objects that have a not-null, not-empty alias field. The generated SQL would look something like:

SELECT * FROM Name WHERE alias IS NOT NULL AND alias != ""

You can also pass multiple arguments to a single call to exclude, which would ensure that only objects that meet every condition get excluded:

Name.objects.exclude(some_field=True, other_field=True)

Here, rows in which some_field and other_field are true get excluded, so we get all rows where both fields are not true. The generated SQL code would look a little like this:

SELECT * FROM Name WHERE NOT (some_field = TRUE AND other_field = TRUE)

Alternatively, if your logic is more complex than that, you could use Django's Q objects:

from django.db.models import Q
Name.objects.exclude(Q(alias__isnull=True) | Q(alias__exact=''))

For more info see this page and this page in the Django docs.

As an aside: My SQL examples are just an analogy--the actual generated SQL code will probably look different. You'll get a deeper understanding of how Django queries work by actually looking at the SQL they generate.

Spring Boot - inject map from application.yml

You can make it even simplier, if you want to avoid extra structures.

    key1: value1
    key2: value2
public class ServiceConfigurationProperties {

  @ConfigurationProperties(prefix = "service.mappings")
  public Map<String, String> serviceMappings() {
    return new HashMap<>();


And then use it as usual, for example with a constructor:

public class Foo {

  private final Map<String, String> serviceMappings;

  public Foo(Map<String, String> serviceMappings) {
    this.serviceMappings = serviceMappings;


MySQL Data - Best way to implement paging?

From the MySQL documentation:

The LIMIT clause can be used to constrain the number of rows returned by the SELECT statement. LIMIT takes one or two numeric arguments, which must both be nonnegative integer constants (except when using prepared statements).

With two arguments, the first argument specifies the offset of the first row to return, and the second specifies the maximum number of rows to return. The offset of the initial row is 0 (not 1):

SELECT * FROM tbl LIMIT 5,10;  # Retrieve rows 6-15

To retrieve all rows from a certain offset up to the end of the result set, you can use some large number for the second parameter. This statement retrieves all rows from the 96th row to the last:

SELECT * FROM tbl LIMIT 95,18446744073709551615;

With one argument, the value specifies the number of rows to return from the beginning of the result set:

SELECT * FROM tbl LIMIT 5;     # Retrieve first 5 rows

In other words, LIMIT row_count is equivalent to LIMIT 0, row_count.

Establish a VPN connection in cmd

I know this is a very old thread but I was looking for a solution to the same problem and I came across this before eventually finding the answer and I wanted to just post it here so somebody else in my shoes would have a shorter trek across the internet.

****Note that you probably have to run cmd.exe as an administrator for this to work**

So here we go, open up the prompt (as an adminstrator) and go to your System32 directory. Then run

C:\Windows\System32>cd ras

Now you'll be in the ras directory. Now it's time to create a temporary file with our connection info that we will then append onto the rasphone.pbk file that will allow us to use the rasdial command.

So to create our temp file run:

C:\Windows\System32\ras>copy con temp.txt

Now it will let you type the contents of the file, which should look like this:

Device=WAN Miniport (IKEv2)

So replace CONNECTION NAME and with the desired connection name and the vpn server address you want.

Make a new line and press Ctrl+Z to finish and save.

Now we will append this onto the rasphone.pbk file that may or may not exist depending on if you already have network connections configured or not. To do this we will run the following command:

C:\Windows\System32\ras>type temp.txt >> rasphone.pbk

This will append the contents of temp.txt to the end of rasphone.pbk, or if rasphone.pbk doesn't exist it will be created. Now we might as well delete our temp file:

C:\Windows\System32\ras>del temp.txt

Now we can connect to our newly configured VPN server with the following command:

C:\Windows\System32\ras>rasdial "CONNECTION NAME" myUsername myPassword

When we want to disconnect we can run:

C:\Windows\System32\ras>rasdial /DISCONNECT

That should cover it! I've included a direct copy and past from the command line of me setting up a connection for and connecting to a canadian vpn server with this method:

Microsoft Windows [Version 6.2.9200]
(c) 2012 Microsoft Corporation. All rights reserved.

C:\Windows\system32>cd ras

C:\Windows\System32\ras>copy con temp.txt
[Canada VPN Connection]
Device=WAN Miniport (IKEv2)
        1 file(s) copied.

C:\Windows\System32\ras>type temp.txt >> rasphone.pbk

C:\Windows\System32\ras>del temp.txt

C:\Windows\System32\ras>rasdial "Canada VPN Connection" justfreevpn 2932
Connecting to Canada VPN Connection...
Verifying username and password...
Connecting to Canada VPN Connection...
Connecting to Canada VPN Connection...
Verifying username and password...
Registering your computer on the network...
Successfully connected to Canada VPN Connection.
Command completed successfully.

C:\Windows\System32\ras>rasdial /DISCONNECT
Command completed successfully.


Hope this helps.

Difference between spring @Controller and @RestController annotation

  • @Controller: This annotation is just a specialized version of @Component and it allows the controller classes to be auto-detected based on classpath scanning.
  • @RestController: This annotation is a specialized version of @Controller which adds @Controller and @ResponseBody annotation automatically so we do not have to add @ResponseBody to our mapping methods.

How to prevent background scrolling when Bootstrap 3 modal open on mobile browsers?

If you use jQuery you can do this with scrollTop

  1. Save the body's vertical scroll position;
  2. Disable scroll on the body;
  3. Show modal;
  4. Close modal;
  5. Reenable scroll on body;
  6. Set saved scroll position.

#modal {_x000D_
    bottom: 0;_x000D_
    position: fixed;_x000D_
    overflow-y: scroll;_x000D_
    overflow-x: hidden;_x000D_
    top: 0;_x000D_
    width: 100%;_x000D_

$('.open-modal').click(function (e) {_x000D_
    scrollTo = $('body').scrollTop();_x000D_
    $('body').css("position", "fixed");_x000D_
$('.close-modal').click(function (e) {_x000D_
    $('body').css("position", "static");_x000D_
    $('body').animate({scrollTop: scrollTo}, 0);_x000D_

How to get the full URL of a Drupal page?

drupal_get_destination() has some internal code that points at the correct place to getthe current internal path. To translate that path into an absolute URL, the url() function should do the trick. If the 'absolute' option is passed in it will generate the full URL, not just the internal path. It will also swap in any path aliases for the current path as well.

$path = isset($_GET['q']) ? $_GET['q'] : '<front>';
$link = url($path, array('absolute' => TRUE));

Disabled form inputs do not appear in the request

I'm updating this answer since is very useful. Just add readonly to the input.

So the form will be:

<form action="/Media/Add">
    <input type="hidden" name="Id" value="123" />
    <input type="textbox" name="Percentage" value="100" readonly/>

How do I reset a sequence in Oracle?

The following script set the sequence to a desired value:

Given a freshly created sequence named PCS_PROJ_KEY_SEQ and table PCS_PROJ:

      PROJ_KEY_MAX       NUMBER := 0;



App not setup: This app is still in development mode


In Settings -> Basic -> Contact Email. (Give your/any email)

STEP 2: in 'App Review' Tab : change

Do you want to make this app and all its live features available to the general public? Yes

And cheers ..

Android SeekBar setOnSeekBarChangeListener

onProgressChanged is called every time you move the cursor.

public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
    textView.setText(String.valueOf(new Integer(progress)));        

so textView should show the progress and alter always if the seekbar is being moved.

Use async await with

A solution using modern-async's map():

import { map } from 'modern-async'

const result = await map(myArray, async (v) => {

The advantage of using that library is that you can control the concurrency using mapLimit() or mapSeries().

Converting Long to Date in Java returns 1970

Works for me. You probably want to multiplz it with 1000, since what you get are the seconds from 1970 and you have to pass the milliseconds from jan 1 1970

EntityType has no key defined error

You don't have to use key attribute all the time. Make sure the mapping file properly addressed the key

this.HasKey(t => t.Key);
this.Property(p => p.Key)

and don't forget to add the mapping in the Repository's OnModelCreating

modelBuilder.Configurations.Add(new PacketHistoryMap());

Eclipse: "'Periodic workspace save.' has encountered a pro?blem."

Just for another data point, none of the above helped my situation. The way I finally got past this issue is that each time Eclipse complained about some folder not being there, I went on my hard drive and created the folder. E.g. after I see

Could not write metadata for '/servers'.
C:\...\.metadata\.plugins\org.eclipse.core.resources\.projects\servers\.markers.snap (The system cannot find the path specified.)

I create the "servers" folder (not the file inside it). This gets me to the next error. I went through 3-4 of these iterations (exiting Eclipse each time to force the save) before the issues went away.

HTH, Mark

Install apps silently, with granted INSTALL_PACKAGES permission

Your first bet is to look into Android's native PackageInstaller. I would recommend modifying that app the way you like, or just extract required functionality.

Specifically, if you look into PackageInstallerActivity and its method onClickListener:

 public void onClick(View v) {
    if(v == mOk) {
        // Start subactivity to actually install the application
        Intent newIntent = new Intent();
        newIntent.setClass(this, InstallAppProgress.class);
    } else if(v == mCancel) {
        // Cancel and finish

Then you'll notice that actual installer is located in InstallAppProgress class. Inspecting that class you'll find that initView is the core installer function, and the final thing it does is call to PackageManager's installPackage function:

public void initView() {
pm.installPackage(mPackageURI, observer, installFlags, installerPackageName);

Next step is to inspect PackageManager, which is abstract class. You'll find installPackage(...) function there. The bad news is that it's marked with @hide. This means it's not directly available (you won't be able to compile with call to this method).

  * @hide
  * ....
  public abstract void installPackage(Uri packageURI,
             IPackageInstallObserver observer, 
             int flags,String installerPackageName); 

But you will be able to access this methods via reflection.

If you are interested in how PackageManager's installPackage function is implemented, take a look at PackageManagerService.


You'll need to get package manager object via Context's getPackageManager(). Then you will call installPackage function via reflection.

Remove stubborn underline from link

You are not applying text-decoration: none; to an anchor (.boxhead a) but to a span element (.boxhead).

Try this:

.boxhead a {
    color: #FFFFFF;
    text-decoration: none;

What is a "web service" in plain English?

Simplified, non-technical explanation: A web serivce allows a PROGRAM to talk to a web page, instead of using your browser to open a web page.

Example: I can go to, and type in my home address, and see a map of where I live in my browser.

But what if you were writing a computer program where you wanted to take an address and show a pretty map, just like Google maps?

Well, you could write a whole new mapping program from scratch, OR you could call a web service that Google maps provides, send it the address, and it will return a graphical map of the location, which you can display in your program.

There is a lot more to it, as some of the other posts go into, but the upshot is that it allows your application to either retrieve information FROM, or submit information TO some resource. Some other examples:

  1. You can use a web service to retrieve information about books at
  2. You can use a similar web service to submit an order to
  3. You could CREATE a web service to allow outside applications to find out about product information within your company
  4. you could create a web service to allow outside applications to submit orders to your company.

System.BadImageFormatException An attempt was made to load a program with an incorrect format

i have same problem what i did i just downloaded 32-bit dll and added it to my bin folder this is solved my problem

Find duplicate entries in a column


  SELECT t.ctn_no
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

...will show you the ctn_no value(s) that have duplicates in your table. Adding criteria to the WHERE will allow you to further tune what duplicates there are:

  SELECT t.ctn_no
   WHERE t.s_ind = 'Y'
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

If you want to see the other column values associated with the duplicate, you'll want to use a self join:

  JOIN (SELECT t.ctn_no
          FROM YOUR_TABLE t
      GROUP BY t.ctn_no
        HAVING COUNT(t.ctn_no) > 1) y ON y.ctn_no = x.ctn_no

Tkinter module not found on Ubuntu

this works for me:

from tkinter import *
root = Tk()
l = Label(root, text="Does it work")

Set date input field's max date to today

A short but may be less readable version of one of the previous answers.

   <script type="text/javascript">

    function DOM_Load (e) {
        $("#datefield").on("click", dateOfBirth_Click);

    function dateOfBirth_Click(e) {
        let today = new Date();
        $("#datefield").prop("max", `${today.getUTCFullYear()}-${(today.getUTCMonth() + 1).toString().padStart(2, "0")}-${today.getUTCDate().toString().padStart(2, "0")}`);


Is there a JSON equivalent of XQuery/XPath?

Json Pointer seem's to be getting growing support too.

How to configure log4j with a properties file

import org.apache.log4j.PropertyConfigurator;

Import this, then:

Properties props = new Properties();
InputStream is = Main.class.getResourceAsStream("/");

try {
} catch (Exception e) {
    // ignore this exception
    log.error("Unable to load log4j properties file.",e);

My java files directory like this:


And log4j directory like this:


How do I mock a static method that returns void with PowerMock?

You can do it the same way you do it with Mockito on real instances. For example you can chain stubs, the following line will make the first call do nothing, then second and future call to getResources will throw the exception :

// the stub of the static method

// the use of the mocked static code
StaticResource.getResource("string"); // do nothing
StaticResource.getResource("string"); // throw Exception

Thanks to a remark of Matt Lachman, note that if the default answer is not changed at mock creation time, the mock will do nothing by default. Hence writing the following code is equivalent to not writing it.


Though that being said, it can be interesting for colleagues that will read the test that you expect nothing for this particular code. Of course this can be adapted depending on how is perceived understandability of the test.

By the way, in my humble opinion you should avoid mocking static code if your crafting new code. At Mockito we think it's usually a hint to bad design, it might lead to poorly maintainable code. Though existing legacy code is yet another story.

Generally speaking if you need to mock private or static method, then this method does too much and should be externalized in an object that will be injected in the tested object.

Hope that helps.


Test method is inconclusive: Test wasn't run. Error?

For who are in rush for test execution, I had to use VS 2017 test explorer to run tests;

enter image description here

enter image description here

What is TypeScript and why would I use it in place of JavaScript?

"TypeScript Fundamentals" -- a Pluralsight video-course by Dan Wahlin and John Papa is a really good, presently (March 25, 2016) updated to reflect TypeScript 1.8, introduction to Typescript.

For me the really good features, beside the nice possibilities for intellisense, are the classes, interfaces, modules, the ease of implementing AMD, and the possibility to use the Visual Studio Typescript debugger when invoked with IE.

To summarize: If used as intended, Typescript can make JavaScript programming more reliable, and easier. It can increase the productivity of the JavaScript programmer significantly over the full SDLC.

Hibernate: get entity by id

In getUserById you shouldn't create a new object (user1) which isn't used. Just assign it to the already (but null) initialized user. Otherwise Hibernate.initialize(user); is actually Hibernate.initialize(null);

Here's the new getUserById (I haven't tested this ;)):

public User getUserById(Long user_id) {
    Session session = null;
    Object user = null;
    try {
        session = HibernateUtil.getSessionFactory().openSession();
        user = (User)session.load(User.class, user_id);
    } catch (Exception e) {
    } finally {
        if (session != null && session.isOpen()) {
    return user;

*ngIf and *ngFor on same element causing error

in html:

<div [ngClass]="{'disabled-field': !show}" *ngFor="let thing of stuff">

in css:

.disabled-field {
    pointer-events: none;
    display: none;

Non-numeric Argument to Binary Operator Error in R

Because your question is phrased regarding your error message and not whatever your function is trying to accomplish, I will address the error.

- is the 'binary operator' your error is referencing, and either CurrentDay or MA (or both) are non-numeric.

A binary operation is a calculation that takes two values (operands) and produces another value (see wikipedia for more). + is one such operator: "1 + 1" takes two operands (1 and 1) and produces another value (2). Note that the produced value isn't necessarily different from the operands (e.g., 1 + 0 = 1).

R only knows how to apply + (and other binary operators, such as -) to numeric arguments:

> 1 + 1
[1] 2
> 1 + 'one'
Error in 1 + "one" : non-numeric argument to binary operator

When you see that error message, it means that you are (or the function you're calling is) trying to perform a binary operation with something that isn't a number.


Your error lies in the use of [ instead of [[. Because Day is a list, subsetting with [ will return a list, not a numeric vector. [[, however, returns an object of the class of the item contained in the list:

> Day <- Transaction(1, 2)["b"]
> class(Day)
[1] "list"
> Day + 1
Error in Day + 1 : non-numeric argument to binary operator

> Day2 <- Transaction(1, 2)[["b"]]
> class(Day2)
[1] "numeric"
> Day2 + 1
[1] 3

Transaction, as you've defined it, returns a list of two vectors. Above, Day is a list contain one vector. Day2, however, is simply a vector.

What's the maximum value for an int in PHP?

From the PHP manual:

The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that's 32 bits signed). PHP does not support unsigned integers. Integer size can be determined using the constant PHP_INT_SIZE, and maximum value using the constant PHP_INT_MAX since PHP 4.4.0 and PHP 5.0.5.

64-bit platforms usually have a maximum value of about 9E18, except on Windows prior to PHP 7, where it was always 32 bit.

How to make program go back to the top of the code instead of closing

You can easily do it with loops, there are two types of loops

For Loops:

for i in range(0,5):
    print 'Hello World'

While Loops:

count = 1
while count <= 5:
    print 'Hello World'
    count += 1

Each of these loops print "Hello World" five times

How to escape the equals sign in properties files

In your specific example you don't need to escape the equals - you only need to escape it if it's part of the key. The properties file format will treat all characters after the first unescaped equals as part of the value.

How to find index of an object by key and value in an javascript array

Using jQuery .each()

var peoples = [_x000D_
  { "attr1": "bob", "attr2": "pizza" },_x000D_
  { "attr1": "john", "attr2": "sushi" },_x000D_
  { "attr1": "larry", "attr2": "hummus" }_x000D_
$.each(peoples, function(index, obj) {_x000D_
   $.each(obj, function(attr, value) {_x000D_
      console.log( attr + ' == ' + value );_x000D_
<script src=""></script>

Using for-loop:

var peoples = [_x000D_
  { "attr1": "bob", "attr2": "pizza" },_x000D_
  { "attr1": "john", "attr2": "sushi" },_x000D_
  { "attr1": "larry", "attr2": "hummus" }_x000D_
for (var i = 0; i < peoples.length; i++) {_x000D_
  for (var key in peoples[i]) {_x000D_
    console.log(key + ' == ' + peoples[i][key]);_x000D_

What is $@ in Bash?

Yes. Please see the man page of bash ( the first thing you go to ) under Special Parameters

Special Parameters

The shell treats several parameters specially. These parameters may only be referenced; assignment to them is not allowed.

* Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, it expands to a single word with the value of each parameter separated by the first character of the IFS special variable. That is, "$*" is equivalent to "$1c$2c...", where c is the first character of the value of the IFS variable. If IFS is unset, the parameters are separated by spaces. If IFS is null, the parameters are joined without intervening separators.

@ Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is, "$@" is equivalent to "$1" "$2" ... If the double-quoted expansion occurs within a word, the expansion of the first parameter is joined with the beginning part of the original word, and the expansion of the last parameter is joined with the last part of the original word. When there are no positional parameters, "$@" and $@ expand to nothing (i.e., they are removed).

Jquery Setting Value of Input Field

You just write this script. use input element for this.


or by id="fsd" you write this code.


pod has unbound PersistentVolumeClaims

You have to define a PersistentVolume providing disc space to be consumed by the PersistentVolumeClaim.

When using storageClass Kubernetes is going to enable "Dynamic Volume Provisioning" which is not working with the local file system.

To solve your issue:

  • Provide a PersistentVolume fulfilling the constraints of the claim (a size >= 100Mi)
  • Remove the storageClass-line from the PersistentVolumeClaim
  • Remove the StorageClass from your cluster

How do these pieces play together?

At creation of the deployment state-description it is usually known which kind (amount, speed, ...) of storage that application will need.
To make a deployment versatile you'd like to avoid a hard dependency on storage. Kubernetes' volume-abstraction allows you to provide and consume storage in a standardized way.

The PersistentVolumeClaim is used to provide a storage-constraint alongside the deployment of an application.

The PersistentVolume offers cluster-wide volume-instances ready to be consumed ("bound"). One PersistentVolume will be bound to one claim. But since multiple instances of that claim may be run on multiple nodes, that volume may be accessed by multiple nodes.

A PersistentVolume without StorageClass is considered to be static.

"Dynamic Volume Provisioning" alongside with a StorageClass allows the cluster to provision PersistentVolumes on demand. In order to make that work, the given storage provider must support provisioning - this allows the cluster to request the provisioning of a "new" PersistentVolume when an unsatisfied PersistentVolumeClaim pops up.

Example PersistentVolume

In order to find how to specify things you're best advised to take a look at the API for your Kubernetes version, so the following example is build from the API-Reference of K8S 1.17:

apiVersion: v1
kind: PersistentVolume
  name: ckan-pv-home
    type: local
    storage: 100Mi
    path: "/mnt/data/ckan"

The PersistentVolumeSpec allows us to define multiple attributes. I chose a hostPath volume which maps a local directory as content for the volume. The capacity allows the resource scheduler to recognize this volume as applicable in terms of resource needs.

Additional Resources:

Get list of filenames in folder with Javascript

The current code will give a list of all files in a folder, assuming it's on the server side you want to list all files:

var fs = require('fs');
var files = fs.readdirSync('/assets/photos/');

What is a loop invariant?

Previous answers have defined a loop invariant in a very good way.

Following is how authors of CLRS used loop invariant to prove correctness of Insertion Sort.

Insertion Sort algorithm(as given in Book):

    for j ? 2 to length[A]
        do key ? A[j]
        // Insert A[j] into the sorted sequence A[1..j-1].
        i ? j - 1
        while i > 0 and A[i] > key
            do A[i + 1] ? A[i]
            i ? i - 1
        A[i + 1] ? key

Loop Invariant in this case: Sub-array[1 to j-1] is always sorted.

Now let us check this and prove that algorithm is correct.

Initialization: Before the first iteration j=2. So sub-array [1:1] is the array to be tested. As it has only one element so it is sorted. Thus invariant is satisfied.

Maintenance: This can be easily verified by checking the invariant after each iteration. In this case it is satisfied.

Termination: This is the step where we will prove the correctness of the algorithm.

When the loop terminates then value of j=n+1. Again loop invariant is satisfied. This means that Sub-array[1 to n] should be sorted.

This is what we want to do with our algorithm. Thus our algorithm is correct.

How to set table name in dynamic SQL query?

This is the best way to get a schema dynamically and add it to the different tables within a database in order to get other information dynamically

select @sql = 'insert #tables SELECT ''[''+SCHEMA_NAME(schema_id)+''.''+name+'']'' AS SchemaTable FROM sys.tables'

exec (@sql)

of course #tables is a dynamic table in the stored procedure

Listing only directories using ls in Bash?

In case you're wondering why output from 'ls -d */' gives you two trailing slashes, like:

[prompt]$ ls -d */
app//  cgi-bin//  lib//        pub//

it's probably because somewhere your shell or session configuration files alias the ls command to a version of ls that includes the -F flag. That flag appends a character to each output name (that's not a plain file) indicating the kind of thing it is. So one slash is from matching the pattern '*/', and the other slash is the appended type indicator.

To get rid of this issue, you could of course define a different alias for ls. However, to temporarily not invoke the alias, you can prepend the command with backslash:

\ls -d */

Best way to pass parameters to jQuery's .load()

In the first case, the data are passed to the script via GET, in the second via POST.

I don't think there are limits to the data size, but the completition of the remote call will of course take longer with great amount of data.

Is the 'as' keyword required in Oracle to define an alias?

According to the select_list Oracle select documentation the AS is optional.

As a personal note I think it is easier to read with the AS

How to set up fixed width for <td>?

In my case I was able to fix that issue by using min-width: 100px instead of width: 100px for the cells th or td.

.table td, .table th {
    min-width: 100px;

How can I set the focus (and display the keyboard) on my EditText programmatically

I tried the top answer by David Merriman and it also didn't work in my case. But I found the suggestion to run this code delayed here and it works like a charm.

val editText = view.findViewById<View>(


    val imm = context.getSystemService(INPUT_METHOD_SERVICE) as? InputMethodManager
    imm?.showSoftInput(editText, InputMethodManager.SHOW_IMPLICIT)
}, 100)

LinkButton Send Value to Code Behind OnClick

Add a CommandName attribute, and optionally a CommandArgument attribute, to your LinkButton control. Then set the OnCommand attribute to the name of your Command event handler.

<asp:LinkButton ID="ENameLinkBtn" runat="server" CommandName="MyValueGoesHere" CommandArgument="OtherValueHere" 
          style="font-weight: 700; font-size: 8pt;" OnCommand="ENameLinkBtn_Command" ><%# Eval("EName") %></asp:LinkButton>

<asp:Label id="Label1" runat="server"/>

Then it will be available when in your handler:

protected void ENameLinkBtn_Command (object sender, CommandEventArgs e)
   Label1.Text = "You chose: " + e.CommandName + " Item " + e.CommandArgument;

More info on MSDN

How to add plus one (+1) to a SQL Server column in a SQL Query

You need both a value and a field to assign it to. The value is TableField + 1, so the assignment is:

SET TableField = TableField + 1

Full width image with fixed height

Set the image's width to 100%, and the image's height will adjust itself:

<img style="width:100%;" id="image" src="...">

If you have a custom CSS, then:


<img id="image" src="...">


    width: 100%;

Also, you could do File -> View Source next time, or maybe Google.

Programmatically navigate using react router V4

As sometimes I prefer to switch routes by Application then by buttons, this is a minimal working example what works for me:

import { Component } from 'react'
import { BrowserRouter as Router, Link } from 'react-router-dom'

class App extends Component {
  constructor(props) {

    /** @type BrowserRouter */
    this.router = undefined

  async handleSignFormSubmit() {
    await magic()

  render() {
    return (
      <Router ref={ el => this.router = el }>
        <Link to="/signin">Sign in</Link>
        <Route path="/signin" exact={true} render={() => (
          <SignPage onFormSubmit={ this.handleSignFormSubmit } />
        )} />

VBA Public Array : how to?

Well, basically what I found is that you can declare the array, but when you set it vba shows you an error.

So I put an special sub to declare global variables and arrays, something like:

Global example(10) As Variant

Sub set_values()

example(1) = 1
example(2) = 1
example(3) = 1
example(4) = 1
example(5) = 1
example(6) = 1
example(7) = 1
example(8) = 1
example(9) = 1
example(10) = 1

End Sub

And whenever I want to use the array, I call the sub first, just in case

call set_values

Msgbox example(5)

Perhaps is not the most correct way, but I hope it works for you

Get JSF managed bean by name in any Servlet related class

I use this:

public static <T> T getBean(Class<T> clazz) {
    try {
        String beanName = getBeanName(clazz);
        FacesContext facesContext = FacesContext.getCurrentInstance();
        return facesContext.getApplication().evaluateExpressionGet(facesContext, "#{" + beanName + "}", clazz);
    //return facesContext.getApplication().getELResolver().getValue(facesContext.getELContext(), null, nomeBean);
    } catch (Exception ex) {
        return null;

public static <T> String getBeanName(Class<T> clazz) {
    ManagedBean managedBean = clazz.getAnnotation(ManagedBean.class);
    String beanName =;

    if (StringHelper.isNullOrEmpty(beanName)) {
        beanName = clazz.getSimpleName();
        beanName = Character.toLowerCase(beanName.charAt(0)) + beanName.substring(1);

    return beanName;

And then call:

MyManageBean bean = getBean(MyManageBean.class);

This way you can refactor your code and track usages without problems.

SQL subquery with COUNT help

Assuming there is a column named business:

SELECT Business, COUNT(*) FROM eventsTable GROUP BY Business

How do I install command line MySQL client on mac?

Open the "MySQL Workbench" DMG file and

# Adjust the path to the version of MySQL Workbench you downloaded
cp "/Volumes/MySQL Workbench 6.3.9.CE/" /usr/local/bin
# Make sure it's executable
chmod +x /usr/local/bin/mysql

Eject the DMG disk

Android Studio - Failed to notify project evaluation listener error

This is neither an exact answer to the question nor a silver bullet. However, if nothing works for you e.g. Invalidate cache & restart, Checking build dependency, Disabling Instant Run (I never advise that) etc.

  1. Add command-line option --stacktrace in Setting > Build, Execution, Deployment > Compiler
  2. Now build/assemble gradle once again. You will have detailed information about the cause. e.g. in my case:

Caused by: org.gradle.internal.resolve.ModuleVersionNotFoundException: Could not find com.squareup.okhttp3:logging-interceptor:3.9.1Net.

I have misspelled the dependency name in module level gradle file. Hope that help

Upload failed You need to use a different version code for your APK because you already have one with version code 2

In my case I had something like this in my AndroidManifest,

      javaCompileOptions {
        annotationProcessorOptions {
            arguments = [
                    'androidManifestFile': 'app\\build\\intermediates\\merged_manifests\\debug\\processDebugManifest\\merged\\AndroidManifest.xml'

here the 'androidManifestFile' location is wrong, changed it to

"androidManifestFile": "$projectDir/src/main/AndroidManifest.xml".toString()

everything worked

How can I show/hide a specific alert with twitter bootstrap?


        function showAlert(){
         setTimeout(function() { 
         }, 5000);


<div class="alert alert-success" id="alert" role="alert" style="display:none;" >YOUR MESSAGE</div>

Java Regex Replace with Capturing Group

How about:

if (regexMatcher.find()) {
    resultString = regexMatcher.replaceAll(
            String.valueOf(3 * Integer.parseInt(;

To get the first match, use #find(). After that, you can use #group(1) to refer to this first match, and replace all matches by the first maches value multiplied by 3.

And in case you want to replace each match with that match's value multiplied by 3:

    Pattern p = Pattern.compile("(\\d{1,2})");
    Matcher m = p.matcher("12 54 1 65");
    StringBuffer s = new StringBuffer();
    while (m.find())
        m.appendReplacement(s, String.valueOf(3 * Integer.parseInt(;

You may want to look through Matcher's documentation, where this and a lot more stuff is covered in detail.

How to send POST in angularjs with multiple params?

You can only send 1 object as a parameter in the body via post. I would change your Post method to

public void Post(ICollection<Product> products)

and in your angular code you would pass up a product array in JSON notation

Convert row names into first column

Or you can use dplyr's add_rownames which does the same thing as David's answer:

df <- tibble::rownames_to_column(df, "VALUE")

UPDATE (mid-2016): (incorporated to the above)

old function called add_rownames() has been deprecated and is being replaced by tibble::rownames_to_column() (same functions, but Hadley refactored dplyr a bit).

In Visual Studio Code How do I merge between two local branches?

Update June 2017 (from VSCode 1.14)

The ability to merge local branches has been added through PR 25731 and commit 89cd05f: accessible through the "Git: merge branch" command.
And PR 27405 added handling the diff3-style merge correctly.

Vahid's answer mention 1.17, but that September release actually added nothing regarding merge.
Only the 1.18 October one added Git conflict markers

From 1.18, with the combination of merge command (1.14) and merge markers (1.18), you truly can do local merges between branches.

Original answer 2016:

The Version Control doc does not mention merge commands, only merge status and conflict support.

Even the latest 1.3 June release does not bring anything new to the VCS front.

This is supported by issue 5770 which confirms you cannot use VS Code as a git mergetool, because:

Is this feature being included in the next iteration, by any chance?

Probably not, this is a big endeavour, since a merge UI needs to be implemented.

That leaves the actual merge to be initiated from command line only.

Git error: src refspec master does not match any

The quick possible answer: When you first successfully clone an empty git repository, the origin has no master branch. So the first time you have a commit to push you must do:

git push origin master

Which will create this new master branch for you. Little things like this are very confusing with git.

If this didn't fix your issue then it's probably a gitolite-related issue:

Your conf file looks strange. There should have been an example conf file that came with your gitolite. Mine looks like this:

repo    phonegap                                                                                                                                                                           
    RW+     =   myusername otherusername                                                                                                                                               

repo    gitolite-admin                                                                                                                                                                         
    RW+     =   myusername                                                                                                                                                               

Please make sure you're setting your conf file correctly.

Gitolite actually replaces the gitolite user's account with a modified shell that doesn't accept interactive terminal sessions. You can see if gitolite is working by trying to ssh into your box using the gitolite user account. If it knows who you are it will say something like "Hi XYZ, you have access to the following repositories: X, Y, Z" and then close the connection. If it doesn't know you, it will just close the connection.

Lastly, after your first git push failed on your local machine you should never resort to creating the repo manually on the server. We need to know why your git push failed initially. You can cause yourself and gitolite more confusion when you don't use gitolite exclusively once you've set it up.

How to implement the Android ActionBar back button?

To achieved this, there are simply two steps,

Step 1: Go to AndroidManifest.xml and in the add the parameter in tag - android:parentActivityName=".home.HomeActivity"

example :

    android:screenOrientation="portrait" />

Step 2: in ActivityDetail add your action for previous page/activity

example :

public boolean onOptionsItemSelected(MenuItem item) {
   switch (item.getItemId()) {
          return true;
   return super.onOptionsItemSelected(item);}

json Uncaught SyntaxError: Unexpected token :

You've told jQuery to expect a JSONP response, which is why jQuery has added the callback=jQuery16406345664265099913_1319854793396&_=1319854793399 part to the URL (you can see this in your dump of the request).

What you're returning is JSON, not JSONP. Your response looks like

{"red" : "#f00"}

and jQuery is expecting something like this:

jQuery16406345664265099913_1319854793396({"red" : "#f00"})

If you actually need to use JSONP to get around the same origin policy, then the server serving colors.json needs to be able to actually return a JSONP response.

If the same origin policy isn't an issue for your application, then you just need to fix the dataType in your jQuery.ajax call to be json instead of jsonp.

Insert NULL value into INT column

Does the column allow null?

Seems to work. Just tested with phpMyAdmin, the column is of type int that allows nulls:

INSERT INTO `database`.`table` (`column`) VALUES (NULL);

Setting Windows PATH for Postgres tools

Settings Windows Path For Postgresql

open my Computer ==>
  right click inside my computer and select properties ==>
    Click on Advanced System Settings ==>
       Environment Variables ==>
          from the System Variables box select "PATH" ==>
             Edit... ==>

then add this at the end of whatever you find their

 ;C:\PostgreSQL\9.2\bin; C:\PostgreSQL\9.2\lib

after that continue to click OK

open cmd/command prompt.... open psql in command prompt with this

psql -U username database

eg. i have a database name FRIENDS and a user MEE.. it will be


you will be then prompted to give the password of the user in question. Thanks

Writing sqlplus output to a file

Also note that the SPOOL output is driven by a few SQLPlus settings:

  • SET LINESIZE nn - maximum line width; if the output is longer it will wrap to display the contents of each result row.

  • SET TRIMSPOOL OFF|ON - if set OFF (the default), every output line will be padded to LINESIZE. If set ON, every output line will be trimmed.

  • SET PAGESIZE nn - number of lines to output for each repetition of the header. If set to zero, no header is output; just the detail.

Those are the biggies, but there are some others to consider if you just want the output without all the SQLPlus chatter.

Loop Through Each HTML Table Column and Get the Data using jQuery

try this

    $("#mprDetailDataTable tr:gt(0)").each(function () {
        var this_row = $(this);
        var productId = $.trim(this_row.find('td:eq(0)').html());//td:eq(0) means first td of this row
        var product = $.trim(this_row.find('td:eq(1)').html())
        var Quantity = $.trim(this_row.find('td:eq(2)').html())

Find a file by name in Visual Studio Code

It's Ctrl+Shift+O / Cmd+Shift+O on mac. You can see it if you close all tabs

AngularJS : ng-model binding not updating when changed with jQuery

AngularJS pass string, numbers and booleans by value while it passes arrays and objects by reference. So you can create an empty object and make your date a property of that object. In that way angular will detect model changes.

In controller


In html

<div ng-controller="yourController">
<input id="selectedDueDate" type="text" ng-model="vm.selectedDate" />

CSS Grid Layout not working in IE11 even with prefixes

The answer has been given by Faisal Khurshid and Michael_B already.
This is just an attempt to make a possible solution more obvious.

For IE11 and below you need to enable grid's older specification in the parent div e.g. body or like here "grid" like so:


then define the amount and width of the columns and rows like e.g. so:

  -ms-grid-columns: 1fr 3fr;
  -ms-grid-rows: 4fr;

finally you need to explicitly tell the browser where your element (item) should be placed in e.g. like so:

  -ms-grid-column: 1;
  -ms-grid-row: 1;

  -ms-grid-column: 2;
  -ms-grid-row: 1;

How to check if the given string is palindrome?


(defun palindrome(x) (string= x (reverse x)))

startForeground fail after upgrade to Android 8.1

Works properly on Andorid 8.1:

Updated sample (without any deprecated code):

public NotificationBattery(Context context) {
    this.mCtx = context;

    mBuilder = new NotificationCompat.Builder(context, CHANNEL_ID)
            .setWhen(System.currentTimeMillis() + 500)

    mRemoteViews = new RemoteViews(context.getPackageName(), R.layout.notification_view_battery);



    mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

    if (AesPrefs.getBooleanRes(R.string.SHOW_BATTERY_NOTIFICATION, true)) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel channel = new NotificationChannel(CHANNEL_ID, context.getString(R.string.notification_title_battery),
            channel.setSound(null, null);
    } else {

Old snipped (it's a different app - not related to the code above):

public int onStartCommand(Intent intent, int flags, final int startId) {
    Log.d(TAG, "onStartCommand");

    String CHANNEL_ONE_ID = "";
    String CHANNEL_ONE_NAME = "Channel One";
    NotificationChannel notificationChannel = null;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
        notificationChannel = new NotificationChannel(CHANNEL_ONE_ID,
        NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

    Bitmap icon = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher);
    Notification notification = new Notification.Builder(getApplicationContext())

    Intent notificationIntent = new Intent(getApplicationContext(), MainActivity.class);
    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
    notification.contentIntent = PendingIntent.getActivity(getApplicationContext(), 0, notificationIntent, 0);

    startForeground(START_FOREGROUND_ID, notification);

    return START_STICKY;

URL to load resources from the classpath in Java

In a Spring Boot app, I used the following to get the file URL,


Daemon Threads Explanation

Let's say you're making some kind of dashboard widget. As part of this, you want it to display the unread message count in your email box. So you make a little thread that will:

  1. Connect to the mail server and ask how many unread messages you have.
  2. Signal the GUI with the updated count.
  3. Sleep for a little while.

When your widget starts up, it would create this thread, designate it a daemon, and start it. Because it's a daemon, you don't have to think about it; when your widget exits, the thread will stop automatically.

Mongoose: CastError: Cast to ObjectId failed for value "[object Object]" at path "_id"

Had the same problem, I just coerced the id into a string.

My schema:

const product = new mongooseClient.Schema({
    retailerID: { type: mongoose.SchemaTypes.ObjectId, required: true, index: true }

And then, when inserting:

retailerID: `${retailer._id}`

Format SQL in SQL Server Management Studio

Late answer, but hopefully worthwhile: The Poor Man's T-SQL Formatter is an open-source (free) T-SQL formatter with complete T-SQL batch/script support (any DDL, any DML), SSMS Plugin, command-line bulk formatter, and other options.

It's available for immediate/online use at, and just today graduated to "version 1.0" (it was in beta version for a few months), having just acquired support for MERGE statements, OUTPUT clauses, and other finicky stuff.

The SSMS Add-in allows you to set your own hotkey (default is Ctrl-K, Ctrl-F, to match Visual Studio), and formats the entire script or just the code you have selected/highlighted, if any. Output formatting is customizable.

In SSMS 2008 it combines nicely with the built-in intelli-sense, effectively providing more-or-less the same base functionality as Red Gate's SQL Prompt (SQL Prompt does, of course, have extra stuff, like snippets, quick object scripting, etc).

Feedback/feature requests are more than welcome, please give it a whirl if you get the chance!

Disclosure: This is probably obvious already but I wrote this library/tool/site, so this answer is also shameless self-promotion :)

python pandas dataframe columns convert to dict key and value

You can also do this if you want to play around with pandas. However, I like punchagan's way.

# replicating your dataframe
lake = pd.DataFrame({'co tp': ['DE Lake', 'Forest', 'FR Lake', 'Forest'], 
                 'area': [10, 20, 30, 40], 
                 'count': [7, 5, 2, 3]})
lake.set_index('co tp', inplace=True)

# to get key value using pandas
area_dict = lake.set_index('area').T.to_dict('records')[0]

output: {10: 7, 20: 5, 30: 2, 40: 3}

NumPy first and last element from array

>>> test = [1,23,4,6,7,8]
>>> from itertools import izip_longest
>>> for e in izip_longest(test, reversed(test)):
    print e

(1, 8)
(23, 7)
(4, 6)
(6, 4)
(7, 23)
(8, 1)

Another option

>>> test = [1,23,4,6,7,8]
>>> start, end = iter(test), reversed(test)
>>> try:
    while True:
        print map(next, [start, end])
except StopIteration:

[1, 8]
[23, 7]
[4, 6]
[6, 4]
[7, 23]
[8, 1]

Get text from pressed button

The view you get passed in on onClick() is the Button you are looking for.

public void onClick(View v) {
    // 1) Possibly check for instance of first 
    Button b = (Button)v;
    String buttonText = b.getText().toString();

1) If you are using a non-anonymous class as onClickListener, you may want to check for the type of the view before casting it, as it may be something different than a Button.

Finding child element of parent pure javascript

Just adding another idea you could use a child selector to get immediate children

document.querySelectorAll(".parent > .child1");

should return all the immediate children with class .child1

What's the best way to determine which version of Oracle client I'm running?

You should put a semicolon at the end of select * from v$version;.

Like this you will get all info you need...

If you are looking just for Oracle for example you can do as:

SQL> select * from v$version where banner like 'Oracle%';

Excel VBA Loop on columns

If you want to stick with the same sort of loop then this will work:

Option Explicit

Sub selectColumns()

Dim topSelection As Integer
Dim endSelection As Integer
topSelection = 2
endSelection = 10

Dim columnSelected As Integer
columnSelected = 1
   With Excel.ThisWorkbook.ActiveSheet
        .Range(.Cells(columnSelected, columnSelected), .Cells(endSelection, columnSelected)).Select
   End With
   columnSelected = columnSelected + 1
Loop Until columnSelected > 10

End Sub


If in reality you just want to loop through every cell in an area of the spreadsheet then use something like this:

Sub loopThroughCells()

'this is the starting point
Dim rwMin As Integer
Dim colMin As Integer
rwMin = 2
colMin = 2

'this is the ending point
Dim rwMax As Integer
Dim colMax As Integer
rwMax = 10
colMax = 5

Dim rwIndex As Integer
Dim colIndex As Integer

For rwIndex = rwMin To rwMax
        For colIndex = colMin To colMax
            Cells(rwIndex, colIndex).Select
        Next colIndex
Next rwIndex

End Sub

Difference between Ctrl+Shift+F and Ctrl+I in Eclipse

Ctrl+Shift+F formats the selected line(s) or the whole source code if you haven't selected any line(s) as per the format specified in your Eclipse, while Ctrl+I gives proper indent to the selected line(s) or the current line if you haven't selected any line(s). try this. or more precisely

The Ant editor that ships with Eclipse can be used to reformat

XML/XHTML/HTML code (with a few configuration options in Window > Preferences > Ant > Editor).

You can right-click a file then

Open With... > Other... > Internal Editors > Ant Editor

Or add a file association between .html (or .xhtml) and that editor with

Window > Preferences > General > Editors > File Associations

Once open in the editor, hit ESC then CTRL-F to reformat.

In VBA get rid of the case sensitivity when comparing words?

There is a statement you can issue at the module level:

Option Compare Text

This makes all "text comparisons" case insensitive. This means the following code will show the message "this is true":

Option Compare Text

Sub testCase()
  If "UPPERcase" = "upperCASE" Then
    MsgBox "this is true: option Compare Text has been set!"
  End If
End Sub

See for example . I'm not sure it will completely solve the problem for all instances (such as the Application.Match function) but it will take care of all the if a=b statements. As for Application.Match - you may want to convert the arguments to either upper case or lower case using the LCase function.

How to use SQL LIKE condition with multiple values in PostgreSQL?

Following query helped me. Instead of using LIKE, you can use ~*.

select id, name from hosts where name ~* 'julia|lena|jack';

How to set dialog to show in full screen?

EDIT Until such time as StackOverflow allows us to version our answers, this is an answer that works for Android 3 and below. Please don't downvote it because it's not working for you now, because it definitely works with older Android versions.

You should only need to add one line to your onCreateDialog() method:

protected Dialog onCreateDialog(int id) {
    //all other dialog stuff (which dialog to display)

    //this line is what you need:
    dialog.getWindow().setFlags(LayoutParams.FLAG_FULLSCREEN, LayoutParams.FLAG_FULLSCREEN);

    return dialog;

Get full URL and query string in Servlet for both HTTP and HTTPS requests

The fact that a HTTPS request becomes HTTP when you tried to construct the URL on server side indicates that you might have a proxy/load balancer (nginx, pound, etc.) offloading SSL encryption in front and forward to your back end service in plain HTTP.

If that's case, check,

  1. whether your proxy has been set up to forward headers correctly (Host, X-forwarded-proto, X-forwarded-for, etc).
  2. whether your service container (E.g. Tomcat) is set up to recognize the proxy in front. For example, Tomcat requires adding secure="true" scheme="https" proxyPort="443" attributes to its Connector
  3. whether your code, or service container is processing the headers correctly. For example, Tomcat automatically replaces scheme, remoteAddr, etc. values when you add RemoteIpValve to its Engine. (see Configuration guide, JavaDoc) so you don't have to process these headers in your code manually.

Incorrect proxy header values could result in incorrect output when request.getRequestURI() or request.getRequestURL() attempts to construct the originating URL.

Disable output buffering

One way to get unbuffered output would be to use sys.stderr instead of sys.stdout or to simply call sys.stdout.flush() to explicitly force a write to occur.

You could easily redirect everything printed by doing:

import sys; sys.stdout = sys.stderr
print "Hello World!"

Or to redirect just for a particular print statement:

print >>sys.stderr, "Hello World!"

To reset stdout you can just do:

sys.stdout = sys.__stdout__

Quick way to clear all selections on a multiselect enabled <select> with jQuery?

$('.clearAll').on('click', function() {_x000D_
<script src=""></script>_x000D_
<select class="dropdown" multiple>_x000D_
  <option value="volvo">Volvo</option>_x000D_
  <option value="saab">Saab</option>_x000D_
  <option value="opel">Opel</option>_x000D_
  <option value="audi">Audi</option>_x000D_
<button class='clearAll'>Clear All Selection</button>

Regular expression search replace in Sublime Text 2

Looking at Sublime Text Unofficial Documentation's article on Search and Replace, it looks like +(.+) is the capture group you might want... but I personally used (.*) and it worked well. To REPLACE in the way you are saying, you might like this conversation in the forums, specifically this post which says to simply use $1 to use the first captured group.

And since pictures are better than words...

Before: before find/replace

After: after find/replace

What does "request for member '*******' in something not a structure or union" mean?

I have enumerated possibly all cases where this error may occur in code and its comments below. Please add to it, if you come across more cases.


typedef struct AStruct TypedefedStruct;

struct AStruct
    int member;

void main()
    /*  Case 1
        Use (->) operator to access structure member with structure pointer, instead
        of dot (.) operator. 
    struct AStruct *aStructObjPtr = (struct AStruct *)malloc(sizeof(struct AStruct));
    //aStructObjPtr.member = 1;      //Error: request for member ‘member’ in something not 
                                      //a structure or union. 
                                      //It should be as below.
    aStructObjPtr->member = 1;
    printf("%d",aStructObjPtr->member); //1

    /*  Case 2
        We can use dot (.) operator with struct variable to access its members, but 
        not with with struct pointer. But we have to ensure we dont forget to wrap 
        pointer variable inside brackets.
    //*aStructObjPtr.member = 2;     //Error, should be as below.
    (*aStructObjPtr).member = 2;
    printf("%d",(*aStructObjPtr).member); //2

    /* Case 3
       Use (->) operator to access structure member with typedefed structure pointer, 
       instead of dot (.) operator. 
    TypedefedStruct *typedefStructObjPtr = (TypedefedStruct *)malloc(sizeof(TypedefedStruct));
    //typedefStructObjPtr.member=3;  //Error, should be as below.
    printf("%d",typedefStructObjPtr->member);  //3

    /*  Case 4
        We can use dot (.) operator with struct variable to access its members, but 
        not with with struct pointer. But we have to ensure we dont forget to wrap 
        pointer variable inside brackets.
    //*typedefStructObjPtr.member = 4;  //Error, should be as below.    
    printf("%d",(*typedefStructObjPtr).member);  //4

    /* Case 5
       We have to be extra carefull when dealing with pointer to pointers to 
       ensure that we follow all above rules.
       We need to be double carefull while putting brackets around pointers.

    //5.1. Access via struct_ptrptr and  ->
    struct AStruct **aStructObjPtrPtr = &aStructObjPtr;
    //*aStructObjPtrPtr->member = 5;  //Error, should be as below.
    (*aStructObjPtrPtr)->member = 5;
    printf("%d",(*aStructObjPtrPtr)->member); //5

    //5.2. Access via struct_ptrptr and .
    //**aStructObjPtrPtr.member = 6;  //Error, should be as below.
    (**aStructObjPtrPtr).member = 6;
    printf("%d",(**aStructObjPtrPtr).member); //6

    //5.3. Access via typedefed_strct_ptrptr and ->
    TypedefedStruct **typedefStructObjPtrPtr = &typedefStructObjPtr;
    //*typedefStructObjPtrPtr->member = 7;  //Error, should be as below.
    (*typedefStructObjPtrPtr)->member = 7;
    printf("%d",(*typedefStructObjPtrPtr)->member); //7

    //5.4. Access via typedefed_strct_ptrptr and .
    //**typedefStructObjPtrPtr->member = 8;  //Error, should be as below.
    (**typedefStructObjPtrPtr).member = 8;
    printf("%d",(**typedefStructObjPtrPtr).member); //8

    //5.5. All cases 5.1 to 5.4 will fail if you include incorrect number of *
    //     Below are examples of such usage of incorrect number *, correspnding
    //     to int values assigned to them

    //(aStructObjPtrPtr)->member = 5; //Error
    //(*aStructObjPtrPtr).member = 6; //Error 
    //(typedefStructObjPtrPtr)->member = 7; //Error 
    //(*typedefStructObjPtrPtr).member = 8; //Error

The underlying ideas are straight:

  • Use . with structure variable. (Cases 2 and 4)
  • Use -> with pointer to structure. (Cases 1 and 3)
  • If you reach structure variable or pointer to structure variable by following pointer, then wrap the pointer inside bracket: (*ptr). and (*ptr)-> vs *ptr. and *ptr-> (All cases except case 1)
  • If you are reaching by following pointers, ensure you have correctly reached pointer to struct or struct whichever is desired. (Case 5, especially 5.5)

How do I wait for a promise to finish before returning the variable of a function?

Instead of returning a resultsArray you return a promise for a results array and then then that on the call site - this has the added benefit of the caller knowing the function is performing asynchronous I/O. Coding concurrency in JavaScript is based on that - you might want to read this question to get a broader idea:

function resultsByName(name)
    var Card = Parse.Object.extend("Card");
    var query = new Parse.Query(Card);
    query.equalTo("name", name.toString());

    var resultsArray = [];

    return query.find({});                           


// later
resultsByName("Some Name").then(function(results){
    // access results here by chaining to the returned promise

You can see more examples of using parse promises with queries in Parse's own blog post about it.

How to fetch the row count for all tables in a SQL SERVER database

Here's a dynamic SQL approach that also gives you the schema as well:

DECLARE @sql nvarchar(MAX)

    @sql = COALESCE(@sql + ' UNION ALL ', '') +
            ''' + + ''' AS ''Schema'',
            ''' + + ''' AS ''Table'',
            COUNT(*) AS Count
            FROM ' + QUOTENAME( + '.' + QUOTENAME(
    FROM sys.schemas s
    INNER JOIN sys.tables t ON t.schema_id = s.schema_id


If needed, it would be trivial to extend this to run over all databases in the instance (join to sys.databases).

How do I remove quotes from a string?

str_replace('"', "", $string);
str_replace("'", "", $string);

I assume you mean quotation marks?

Otherwise, go for some regex, this will work for html quotes for example:

preg_replace("/<!--.*?-->/", "", $string);

C-style quotes:

preg_replace("/\/\/.*?\n/", "\n", $string);

CSS-style quotes:

preg_replace("/\/*.*?\*\//", "", $string);

bash-style quotes:

preg-replace("/#.*?\n/", "\n", $string);

Etc etc...

Java 8 Filter Array Using Lambda

even simpler, adding up to String[],

use built-in filter filter(StringUtils::isNotEmpty) of org.apache.commons.lang3

import org.apache.commons.lang3.StringUtils;

    String test = "a\nb\n\nc\n";
    String[] lines = test.split("\\n", -1);

    String[]  result =[]::new);

and output: [a, b, , c, ] [a, b, c]

Using a dispatch_once singleton model in Swift

I would suggest an enum, as you would use in Java, e.g.

enum SharedTPScopeManager: TPScopeManager {
    case Singleton

How to determine the encoding of text?

It is, in principle, impossible to determine the encoding of a text file, in the general case. So no, there is no standard Python library to do that for you.

If you have more specific knowledge about the text file (e.g. that it is XML), there might be library functions.

Why is there no SortedList in Java?

List iterators guarantee first and foremost that you get the list's elements in the internal order of the list (aka. insertion order). More specifically it is in the order you've inserted the elements or on how you've manipulated the list. Sorting can be seen as a manipulation of the data structure, and there are several ways to sort the list.

I'll order the ways in the order of usefulness as I personally see it:

1. Consider using Set or Bag collections instead

NOTE: I put this option at the top because this is what you normally want to do anyway.

A sorted set automatically sorts the collection at insertion, meaning that it does the sorting while you add elements into the collection. It also means you don't need to manually sort it.

Furthermore if you are sure that you don't need to worry about (or have) duplicate elements then you can use the TreeSet<T> instead. It implements SortedSet and NavigableSet interfaces and works as you'd probably expect from a list:

TreeSet<String> set = new TreeSet<String>();
// automatically sorts natural order when adding

for (String s : set) {
// Prints out "cat" and "lol"

If you don't want the natural ordering you can use the constructor parameter that takes a Comparator<T>.

Alternatively, you can use Multisets (also known as Bags), that is a Set that allows duplicate elements, instead and there are third-party implementations of them. Most notably from the Guava libraries there is a TreeMultiset, that works a lot like the TreeSet.

2. Sort your list with Collections.sort()

As mentioned above, sorting of Lists is a manipulation of the data structure. So for situations where you need "one source of truth" that will be sorted in a variety of ways then sorting it manually is the way to go.

You can sort your list with the java.util.Collections.sort() method. Here is a code sample on how:

List<String> strings = new ArrayList<String>()

for (String s : strings) {
// Prints out "cat" and "lol"

Using comparators

One clear benefit is that you may use Comparator in the sort method. Java also provides some implementations for the Comparator such as the Collator which is useful for locale sensitive sorting strings. Here is one example:

Collator usCollator = Collator.getInstance(Locale.US);
usCollator.setStrength(Collator.PRIMARY); // ignores casing

Collections.sort(strings, usCollator);

Sorting in concurrent environments

Do note though that using the sort method is not friendly in concurrent environments, since the collection instance will be manipulated, and you should consider using immutable collections instead. This is something Guava provides in the Ordering class and is a simple one-liner:

List<string> sorted = Ordering.natural().sortedCopy(strings);

3. Wrap your list with java.util.PriorityQueue

Though there is no sorted list in Java there is however a sorted queue which would probably work just as well for you. It is the java.util.PriorityQueue class.

Nico Haase linked in the comments to a related question that also answers this.

In a sorted collection you most likely don't want to manipulate the internal data structure which is why PriorityQueue doesn't implement the List interface (because that would give you direct access to its elements).

Caveat on the PriorityQueue iterator

The PriorityQueue class implements the Iterable<E> and Collection<E> interfaces so it can be iterated as usual. However, the iterator is not guaranteed to return elements in the sorted order. Instead (as Alderath points out in the comments) you need to poll() the queue until empty.

Note that you can convert a list to a priority queue via the constructor that takes any collection:

List<String> strings = new ArrayList<String>()

PriorityQueue<String> sortedStrings = new PriorityQueue(strings);
while(!sortedStrings.isEmpty()) {
// Prints out "cat" and "lol"

4. Write your own SortedList class

NOTE: You shouldn't have to do this.

You can write your own List class that sorts each time you add a new element. This can get rather computation heavy depending on your implementation and is pointless, unless you want to do it as an exercise, because of two main reasons:

  1. It breaks the contract that List<E> interface has because the add methods should ensure that the element will reside in the index that the user specifies.
  2. Why reinvent the wheel? You should be using the TreeSet or Multisets instead as pointed out in the first point above.

However, if you want to do it as an exercise here is a code sample to get you started, it uses the AbstractList abstract class:

public class SortedList<E> extends AbstractList<E> {

    private ArrayList<E> internalList = new ArrayList<E>();

    // Note that add(E e) in AbstractList is calling this one
    public void add(int position, E e) {
        Collections.sort(internalList, null);

    public E get(int i) {
        return internalList.get(i);

    public int size() {
        return internalList.size();


Note that if you haven't overridden the methods you need, then the default implementations from AbstractList will throw UnsupportedOperationExceptions.

iOS application: how to clear notifications?

Maybe in case there are scheduled alarms and uncleared app icon badges.

NSArray *scheduledLocalNotifications = [application scheduledLocalNotifications];
NSInteger applicationIconBadgeNumber = [application applicationIconBadgeNumber];

[application cancelAllLocalNotifications];
[application setApplicationIconBadgeNumber:0];

for (UILocalNotification* scheduledLocalNotification in scheduledLocalNotifications) {
    [application scheduleLocalNotification:scheduledLocalNotification];
[application setApplicationIconBadgeNumber:applicationIconBadgeNumber];

HTTP Error 404.3-Not Found in IIS 7.5

I was having trouble accessing wcf service hosted locally in IIS. Running aspnet_regiis.exe -i wasn't working.

However, I fortunately came across the following:

Rahul's blog

which informs that servicemodelreg also needs to be run:

Run Visual Studio 2008 Command Prompt as “Administrator”. Navigate to C:\Windows\Microsoft.NET\Framework\v3.0\Windows Communication Foundation. Run this command servicemodelreg –i.

How to confirm RedHat Enterprise Linux version?

That's the RHEL release version.

You can see the kernel version by typing uname -r. It'll be 2.6.something.

Cannot find "Package Explorer" view in Eclipse

Try Window > Open Perspective > Java Browsing or some other Java perspectives

TypeError: no implicit conversion of Symbol into Integer

myHash.each{|item|..} is returning you array object for item iterative variable like the following :--

[:company_name, "MyCompany"]
[:street, "Mainstreet"]
[:postcode, "1234"]
[:city, "MyCity"]
[:free_seats, "3"]

You should do this:--

def format
  output =
  myHash.each do |k, v|
    output[k] = cleanup(v)

How to convert .pem into .key?

just as a .crt file is in .pem format, a .key file is also stored in .pem format. Assuming that the cert is the only thing in the .crt file (there may be root certs in there), you can just change the name to .pem. The same goes for a .key file. Which means of course that you can rename the .pem file to .key.

Which makes gtrig's answer the correct one. I just thought I'd explain why.

Input type for HTML form for integer

If you're using HTML5, you should use the input type number. If you are using xhtml or html 4, input type should be text.

How to force a html5 form validation without submitting it via jQuery

Here is a more general way that is a bit cleaner:

Create your form like this (can be a dummy form that does nothing):

<form class="validateDontSubmit">

Bind all forms that you dont really want to submit:

$(document).on('submit','.validateDontSubmit',function (e) {
    //prevent the form from doing a submit
    return false;

Now lets say you have an <a> (within the <form>) that on click you want to validate the form:

  //Leverage the HTML5 validation w/ ajax. Have to submit to get em. Wont actually submit cuz form
  //has .validateDontSubmit class
  var $theForm = $(this).closest('form');
  //Some browsers don't implement checkValidity
  if (( typeof($theForm[0].checkValidity) == "function" ) && !$theForm[0].checkValidity()) {

  //if you've gotten here - play on playa'

Few notes here:

  • I have noticed that you don't have to actually submit the form for validation to occur - the call to checkValidity() is enough (at least in chrome). If others could add comments with testing this theory on other browsers I'll update this answer.
  • The thing that triggers the validation does not have to be within the <form>. This was just a clean and flexible way to have a general purpose solution..

How to check if X server is running?

I wrote xdpyprobe program which is intended for this purpose. Unlike xset, xdpyinfo and other general tools, it does not do any extra actions (just checks X server and exits) and it may not produce any output (if "-q" option is specified).

How to make primary key as autoincrement for Room Persistence lib

You can add @PrimaryKey(autoGenerate = true) like this:

data class Food(
        var foodName: String, 
        var foodDesc: String, 
        var protein: Double, 
        var carbs: Double, 
        var fat: Double
    @PrimaryKey(autoGenerate = true)
    var foodId: Int = 0 // or foodId: Int? = null
    var calories: Double = 0.toDouble()

Way to create multiline comments in Bash?

Simple solution, not much smart:

Temporarily block a part of a script:

if false; then
    while you respect syntax a bit, please
    do write here (almost) whatever you want.
    but when you are
    done # write

A bit sophisticated version:

time_of_debug=false # Let's set this variable at the beginning of a script

if $time_of_debug; then # in a middle of the script  
    echo I keep this code aside until there is the time of debug!

VBA, if a string contains a certain letter


If myString like "*A*" Then

How to get the first five character of a String

Append five whitespace characters then cut off the first five and trim the result. The number of spaces you append should match the number you are cutting. Be sure to include the parenthesis before .Substring(0,X) or you'll append nothing.

string str = (yourStringVariable + "    ").Substring(0,5).Trim();

With this technique you won't have to worry about the ArgumentOutOfRangeException mentioned in other answers.

Iterate a list with indexes in Python

Here it is a solution using map function:

>>> a = [3, 7, 19]
>>> map(lambda x: (x, a[x]), range(len(a)))
[(0, 3), (1, 7), (2, 19)]

And a solution using list comprehensions:

>>> a = [3,7,19]
>>> [(x, a[x]) for x in range(len(a))]
[(0, 3), (1, 7), (2, 19)]