Programs & Examples On #Media library

Wordpress - Images not showing up in the Media Library

Did you ever change the directory of your Wordpress install?

I had a problem with not finding my uploaded images after changing the Wordpress location on my server. In Wordpress, I went to Dashboard-> Settings -> Media and changed the uploads folder in the "Store uploads in this folder" field.

Slide right to left Android Animations

For sliding both activity (old and new) same direction:

left_in.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="300"
    android:fromXDelta="-100%"
    android:toXDelta="0%"
    android:interpolator="@android:anim/decelerate_interpolator"
     />

right_in.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="300"
    android:fromXDelta="100%"
    android:toXDelta="0%"
    android:interpolator="@android:anim/decelerate_interpolator"
     />

left_out.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="300"
    android:fromXDelta="0%"
    android:interpolator="@android:anim/decelerate_interpolator"
    android:toXDelta="-100%" />

right_out.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="300"
    android:fromXDelta="0%"
    android:interpolator="@android:anim/decelerate_interpolator"
    android:toXDelta="100%" />

startActivity transition:

overridePendingTransition(R.anim.right_in, R.anim.left_out);

onBackPressed transition:

overridePendingTransition(R.anim.left_in, R.anim.right_out);

How to specify "does not contain" in dplyr filter

Note that %in% returns a logical vector of TRUE and FALSE. To negate it, you can use ! in front of the logical statement:

SE_CSVLinelist_filtered <- filter(SE_CSVLinelist_clean, 
 !where_case_travelled_1 %in% 
   c('Outside Canada','Outside province/territory of residence but within Canada'))

Regarding your original approach with -c(...), - is a unary operator that "performs arithmetic on numeric or complex vectors (or objects which can be coerced to them)" (from help("-")). Since you are dealing with a character vector that cannot be coerced to numeric or complex, you cannot use -.

Running an Excel macro via Python?

For Python 3.7 or later,(2018-10-10), I have to combine both @Alejandro BR and SMNALLY's answer, coz @Alejandro forget to define wincl.

import os, os.path
import win32com.client
if os.path.exists('C:/Users/jz/Desktop/test.xlsm'):
    excel_macro = win32com.client.DispatchEx("Excel.Application") # DispatchEx is required in the newest versions of Python.
    excel_path = os.path.expanduser('C:/Users/jz/Desktop/test.xlsm')
    workbook = excel_macro.Workbooks.Open(Filename = excel_path, ReadOnly =1)
    excel_macro.Application.Run("test.xlsm!Module1.Macro1") # update Module1 with your module, Macro1 with your macro
    workbook.Save()
    excel_macro.Application.Quit()  
    del excel_macro

OSX - How to auto Close Terminal window after the "exit" command executed.

In a terminal window, you can type:

kill -9 $(ps -p $PPID -o ppid=)

This will kill the Terminal application process, which is the parent of the parent of the current process, as seen by the kill command.

To close a Terminal window from within a running script, you need to go up one more level in the process hierarchy like this:

kill -9 $(ps -p $(ps -p $PPID -o ppid=) -o ppid=) 

Latex - Change margins of only a few pages

Look up \enlargethispage in some LaTeX reference.

Syntax for creating a two-dimensional array in Java

You can create them just the way others have mentioned. One more point to add: You can even create a skewed two-dimensional array with each row, not necessarily having the same number of collumns, like this:

int array[][] = new int[3][];
array[0] = new int[3];
array[1] = new int[2];
array[2] = new int[5];

How to implement class constructor in Visual Basic?

If you mean VB 6, that would be Private Sub Class_Initialize().

http://msdn.microsoft.com/en-us/library/55yzhfb2(VS.80).aspx

If you mean VB.NET it is Public Sub New() or Shared Sub New().

How to check if a view controller is presented modally or pushed on a navigation stack?

Assuming that all viewControllers that you present modally are wrapped inside a new navigationController (which you should always do anyway), you can add this property to your VC.

private var wasPushed: Bool {
    guard let vc = navigationController?.viewControllers.first where vc == self else {
        return true
    }

    return false
}

What is the difference between varchar and nvarchar?

I would say, it depends.

If you develop a desktop application, where the OS works in Unicode (like all current Windows systems) and language does natively support Unicode (default strings are Unicode, like in Java or C#), then go nvarchar.

If you develop a web application, where strings come in as UTF-8, and language is PHP, which still does not support Unicode natively (in versions 5.x), then varchar will probably be a better choice.

How to rename with prefix/suffix?

I've seen people mention a rename command, but it is not routinely available on Unix systems (as opposed to Linux systems, say, or Cygwin - on both of which, rename is an executable rather than a script). That version of rename has a fairly limited functionality:

rename from to file ...

It replaces the from part of the file names with the to, and the example given in the man page is:

rename foo foo0 foo? foo??

This renames foo1 to foo01, and foo10 to foo010, etc.

I use a Perl script called rename, which I originally dug out from the first edition Camel book, circa 1992, and then extended, to rename files.

#!/bin/perl -w
#
# @(#)$Id: rename.pl,v 1.7 2008/02/16 07:53:08 jleffler Exp $
#
# Rename files using a Perl substitute or transliterate command

use strict;
use Getopt::Std;

my(%opts);
my($usage) = "Usage: $0 [-fnxV] perlexpr [filenames]\n";
my($force) = 0;
my($noexc) = 0;
my($trace) = 0;

die $usage unless getopts('fnxV', \%opts);

if ($opts{V})
{
    printf "%s\n", q'RENAME Version $Revision: 1.7 $ ($Date: 2008/02/16 07:53:08 $)';
    exit 0;
}
$force = 1 if ($opts{f});
$noexc = 1 if ($opts{n});
$trace = 1 if ($opts{x});

my($op) = shift;
die $usage unless defined $op;

if (!@ARGV) {
    @ARGV = <STDIN>;
    chop(@ARGV);
}

for (@ARGV)
{
    if (-e $_ || -l $_)
    {
        my($was) = $_;
        eval $op;
        die $@ if $@;
        next if ($was eq $_);
        if ($force == 0 && -f $_)
        {
            print STDERR "rename failed: $was - $_ exists\n";
        }
        else
        {
            print "+ $was --> $_\n" if $trace;
            print STDERR "rename failed: $was - $!\n"
                unless ($noexc || rename($was, $_));
        }
    }
    else
    {
        print STDERR "$_ - $!\n";
    }
}

This allows you to write any Perl substitute or transliterate command to map file names. In the specific example requested, you'd use:

rename 's/^/new./' original.filename

Android intent for playing video?

following code works just fine for me.

Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(movieurl));
startActivity(intent);

how to prevent css inherit

Override the values present in the outer UL with values in inner UL.

Downloading a file from spring controllers

If it helps anyone. You can do what the accepted answer by Infeligo has suggested but just put this extra bit in the code for a forced download.

response.setContentType("application/force-download");

How do I trim() a string in angularjs?

use trim() method of javascript after all angularjs is also a javascript framework and it is not necessary to put $ to apply trim()

for example

var x="hello world";
x=x.trim()

CodeIgniter - accessing $config variable in view

$this->config->item() works fine.

For example, if the config file contains $config['foo'] = 'bar'; then $this->config->item('foo') == 'bar'

Remove Backslashes from Json Data in JavaScript

tl;dr: You don't have to remove the slashes, you have nested JSON, and hence have to decode the JSON twice: DEMO (note I used double slashes in the example, because the JSON is inside a JS string literal).


I assume that your actual JSON looks like

{"data":"{\n \"taskNames\" : [\n \"01 Jan\",\n \"02 Jan\",\n \"03 Jan\",\n \"04 Jan\",\n \"05 Jan\",\n \"06 Jan\",\n \"07 Jan\",\n \"08 Jan\",\n \"09 Jan\",\n \"10 Jan\",\n \"11 Jan\",\n \"12 Jan\",\n \"13 Jan\",\n \"14 Jan\",\n \"15 Jan\",\n \"16 Jan\",\n \"17 Jan\",\n \"18 Jan\",\n \"19 Jan\",\n \"20 Jan\",\n \"21 Jan\",\n \"22 Jan\",\n \"23 Jan\",\n \"24 Jan\",\n \"25 Jan\",\n \"26 Jan\",\n \"27 Jan\"]}"}

I.e. you have a top level object with one key, data. The value of that key is a string containing JSON itself. This is usually because the server side code didn't properly create the JSON. That's why you see the \" inside the string. This lets the parser know that " is to be treated literally and doesn't terminate the string.

So you can either fix the server side code, so that you don't double encode the data, or you have to decode the JSON twice, e.g.

var data = JSON.parse(JSON.parse(json).data));

What does this thread join code mean?

What does this thread join code mean?

To quote from the Thread.join() method javadocs:

join() Waits for this thread to die.

There is a thread that is running your example code which is probably the main thread.

  1. The main thread creates and starts the t1 and t2 threads. The two threads start running in parallel.
  2. The main thread calls t1.join() to wait for the t1 thread to finish.
  3. The t1 thread completes and the t1.join() method returns in the main thread. Note that t1 could already have finished before the join() call is made in which case the join() call will return immediately.
  4. The main thread calls t2.join() to wait for the t2 thread to finish.
  5. The t2 thread completes (or it might have completed before the t1 thread did) and the t2.join() method returns in the main thread.

It is important to understand that the t1 and t2 threads have been running in parallel but the main thread that started them needs to wait for them to finish before it can continue. That's a common pattern. Also, t1 and/or t2 could have finished before the main thread calls join() on them. If so then join() will not wait but will return immediately.

t1.join() means cause t2 to stop until t1 terminates?

No. The main thread that is calling t1.join() will stop running and wait for the t1 thread to finish. The t2 thread is running in parallel and is not affected by t1 or the t1.join() call at all.

In terms of the try/catch, the join() throws InterruptedException meaning that the main thread that is calling join() may itself be interrupted by another thread.

while (true) {

Having the joins in a while loop is a strange pattern. Typically you would do the first join and then the second join handling the InterruptedException appropriately in each case. No need to put them in a loop.

Removing elements with Array.map in JavaScript

First you can use map and with chaining you can use filter

state.map(item => {
            if(item.id === action.item.id){   
                    return {
                        id : action.item.id,
                        name : item.name,
                        price: item.price,
                        quantity : item.quantity-1
                    }

            }else{
                return item;
            }
        }).filter(item => {
            if(item.quantity <= 0){
                return false;
            }else{
                return true;
            }
        });

Python: No acceptable C compiler found in $PATH when installing python

If you are using alphine with docker, do this:

apk --update add gcc make g++ zlib-dev

The filename, directory name, or volume label syntax is incorrect inside batch

set myPATH="C:\Users\DEB\Downloads\10.1.1.0.4"
cd %myPATH%
  • The single quotes do not indicate a string, they make it starts: 'C:\ instead of C:\ so

  • %name% is the usual syntax for expanding a variable, the !name! syntax needs to be enabled using the command setlocal ENABLEDELAYEDEXPANSION first, or by running the command prompt with CMD /V:ON.

  • Don't use PATH as your name, it is a system name that contains all the locations of executable programs. If you overwrite it, random bits of your script will stop working. If you intend to change it, you need to do set PATH=%PATH%;C:\Users\DEB\Downloads\10.1.1.0.4 to keep the current PATH content, and add something to the end.

How to prevent a background process from being stopped after closing SSH client in Linux

When the session is closed the process receives the SIGHUP signal which it is apparently not catching. You can use the nohup command when launching the process or the bash built-in command disown -h after starting the process to prevent this from happening:

> help disown
disown: disown [-h] [-ar] [jobspec ...]
     By default, removes each JOBSPEC argument from the table of active jobs.
    If the -h option is given, the job is not removed from the table, but is
    marked so that SIGHUP is not sent to the job if the shell receives a
    SIGHUP.  The -a option, when JOBSPEC is not supplied, means to remove all
    jobs from the job table; the -r option means to remove only running jobs.

Reload a DIV without reloading the whole page

try this

<script type="text/javascript">
window.onload = function(){


var auto_refresh = setInterval(
function ()
{
$('.View').html('');
$('.View').load('Small.php').fadeIn("slow");
}, 15000); // refresh every 15000 milliseconds

}
</script>

Selenium Webdriver: Entering text into text field

Agree with Subir Kumar Sao and Faiz.

element_enter.findElement(By.xpath("//html/body/div[1]/div[3]/div[1]/form/div/div/input")).sendKeys(barcode);

Ansible: copy a directory content to another directory

I found a workaround for recursive copying from remote to remote :

- name: List files in /usr/share/easy-rsa
  find:
    path: /usr/share/easy-rsa
    recurse: yes
    file_type: any
  register: find_result

- name: Create the directories
  file:
    path: "{{ item.path | regex_replace('/usr/share/easy-rsa','/etc/easy-rsa') }}"
    state: directory
    mode: "{{ item.mode }}"
  with_items:
    - "{{ find_result.files }}"
  when:
    - item.isdir

- name: Copy the files
  copy:
    src: "{{ item.path }}"
    dest: "{{ item.path | regex_replace('/usr/share/easy-rsa','/etc/easy-rsa') }}"
    remote_src: yes
    mode: "{{ item.mode }}"
  with_items:
    - "{{ find_result.files }}"
  when:
    - item.isdir == False

How to round up the result of integer division?

For records == 0, rjmunro's solution gives 1. The correct solution is 0. That said, if you know that records > 0 (and I'm sure we've all assumed recordsPerPage > 0), then rjmunro solution gives correct results and does not have any of the overflow issues.

int pageCount = 0;
if (records > 0)
{
    pageCount = (((records - 1) / recordsPerPage) + 1);
}
// no else required

All the integer math solutions are going to be more efficient than any of the floating point solutions.

How to create user for a db in postgresql?

Create the user with a password :

http://www.postgresql.org/docs/current/static/sql-createuser.html

CREATE USER name [ [ WITH ] option [ ... ] ]

where option can be:

      SUPERUSER | NOSUPERUSER
    | CREATEDB | NOCREATEDB
    | CREATEROLE | NOCREATEROLE
    | CREATEUSER | NOCREATEUSER
    | INHERIT | NOINHERIT
    | LOGIN | NOLOGIN
    | REPLICATION | NOREPLICATION
    | CONNECTION LIMIT connlimit
    | [ ENCRYPTED | UNENCRYPTED ] PASSWORD 'password'
    | VALID UNTIL 'timestamp'
    | IN ROLE role_name [, ...]
    | IN GROUP role_name [, ...]
    | ROLE role_name [, ...]
    | ADMIN role_name [, ...]
    | USER role_name [, ...]
    | SYSID uid

Then grant the user rights on a specific database :

http://www.postgresql.org/docs/current/static/sql-grant.html

Example :

grant all privileges on database db_name to someuser;

Using a PHP variable in a text input value = statement

Solution

You are missing an echo. Each time that you want to show the value of a variable to HTML you need to echo it.

<input type="text" name="idtest" value="<?php echo $idtest; ?>" >

Note: Depending on the value, your echo is the function you use to escape it like htmlspecialchars.

How to read data from java properties file using Spring Boot

We can read properties file in spring boot using 3 way

1. Read value from application.properties Using @Value

map key as

public class EmailService {

 @Value("${email.username}")
 private String username;

}

2. Read value from application.properties Using @ConfigurationProperties

In this we will map prefix of key using ConfigurationProperties and key name is same as field of class

  @Component
   @ConfigurationProperties("email")
    public class EmailConfig {

        private String   username;
    }

3. Read application.properties Using using Environment object

public class EmailController {

@Autowired
private Environment env;

@GetMapping("/sendmail")
public void sendMail(){     
    System.out.println("reading value from application properties file  using Environment ");
    System.out.println("username ="+ env.getProperty("email.username"));
    System.out.println("pwd ="+ env.getProperty("email.pwd"));
}

Reference : how to read value from application.properties in spring boot

cd into directory without having permission

Unless you have sudo permissions to change it or its in your own usergroup/account you will not be able to get into it.

Check out man chmod in the terminal for more information about changing permissions of a directory.

How to delete specific columns with VBA?

You were just missing the second half of the column statement telling it to remove the entire column, since most normal Ranges start with a Column Letter, it was looking for a number and didn't get one. The ":" gets the whole column, or row.

I think what you were looking for in your Range was this:

Range("C:C,F:F,I:I,L:L,O:O,R:R").Delete

Just change the column letters to match your needs.

Reading NFC Tags with iPhone 6 / iOS 8

I think it will be sometime before we get to see access to the NFC as the pure security side of it like for example being able to walk past somebody brush past them and & get your phone to the zap the card details or simply Wave your phone over someone's wallet which They left on the desk.

I think the first step is for Apple to talk to banks and find more ways of securing cards and NFC before This will be allowed

I need to convert an int variable to double

I think you should casting variable or use Integer class by call out method doubleValue().

socket.shutdown vs socket.close

it's mentioned right in the Socket Programming HOWTO (py2/py3)

Disconnecting

Strictly speaking, you’re supposed to use shutdown on a socket before you close it. The shutdown is an advisory to the socket at the other end. Depending on the argument you pass it, it can mean “I’m not going to send anymore, but I’ll still listen”, or “I’m not listening, good riddance!”. Most socket libraries, however, are so used to programmers neglecting to use this piece of etiquette that normally a close is the same as shutdown(); close(). So in most situations, an explicit shutdown is not needed.

...

Calculate the center point of multiple latitude/longitude coordinate pairs

If you are interested in obtaining a very simplified 'center' of the points (for example, to simply center a map to the center of your gmaps polygon), then here's a basic approach that worked for me.

public function center() {
    $minlat = false;
    $minlng = false;
    $maxlat = false;
    $maxlng = false;
    $data_array = json_decode($this->data, true);
    foreach ($data_array as $data_element) {
        $data_coords = explode(',',$data_element);
        if (isset($data_coords[1])) {
            if ($minlat === false) { $minlat = $data_coords[0]; } else { $minlat = ($data_coords[0] < $minlat) ? $data_coords[0] : $minlat; }
            if ($maxlat === false) { $maxlat = $data_coords[0]; } else { $maxlat = ($data_coords[0] > $maxlat) ? $data_coords[0] : $maxlat; }
            if ($minlng === false) { $minlng = $data_coords[1]; } else { $minlng = ($data_coords[1] < $minlng) ? $data_coords[1] : $minlng; }
            if ($maxlng === false) { $maxlng = $data_coords[1]; } else { $maxlng = ($data_coords[1] > $maxlng) ? $data_coords[1] : $maxlng; }
        }
    }
    $lat = $maxlat - (($maxlat - $minlat) / 2);
    $lng = $maxlng - (($maxlng - $minlng) / 2);
    return $lat.','.$lng;
}

This returns the middle lat/lng coordinate for the center of a polygon.

Open application after clicking on Notification

Use below code for create notification for open activity. It works for me. For full code

 Intent myIntent = new Intent(context, DoSomething.class);
 PendingIntent pendingIntent = PendingIntent.getActivity(
        context, 
        0, 
        myIntent, 
        Intent.FLAG_ACTIVITY_NEW_TASK);

 myNotification = new NotificationCompat.Builder(context)
   .setContentTitle("Exercise of Notification!")
   .setContentText("Do Something...")
   .setTicker("Notification!")
   .setWhen(System.currentTimeMillis())
   .setContentIntent(pendingIntent)
   .setDefaults(Notification.DEFAULT_SOUND)
   .setAutoCancel(true)
   .setSmallIcon(R.drawable.ic_launcher)
   .build();

 notificationManager = 
   (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
 notificationManager.notify(MY_NOTIFICATION_ID, myNotification);

Clearing _POST array fully

The solutions so far don't work because the POST data is stored in the headers. A redirect solves this issue according this this post.

How to delete $_POST variable upon pressing 'Refresh' button on browser with PHP?

jsonify a SQLAlchemy result set in Flask

Here's my approach: https://github.com/n0nSmoker/SQLAlchemy-serializer

pip install SQLAlchemy-serializer

You can easily add mixin to your model and than just call .to_dict() method on it's instance

You also can write your own mixin on base of SerializerMixin

How can I create objects while adding them into a vector?

You cannot insert a class into a vector, you can insert an object (provided that it is of the proper type or convertible) of a class though.

If the type Player has a default constructor, you can create a temporary object by doing Player(), and that should work for your case:

vectorOfGamers.push_back(Player());

SQL SERVER: Get total days between two dates

This is working for me -

SELECT DATEDIFF(DAY, startdate, enddate) AS DayCount

Example : SELECT DATEDIFF(DAY, '11/30/2019', GETDATE()) AS DayCount

Getting the document object of an iframe

This is the code I use:

var ifrm = document.getElementById('myFrame');
ifrm = (ifrm.contentWindow) ? ifrm.contentWindow : (ifrm.contentDocument.document) ? ifrm.contentDocument.document : ifrm.contentDocument;
ifrm.document.open();
ifrm.document.write('Hello World!');
ifrm.document.close();

contentWindow vs. contentDocument

  • IE (Win) and Mozilla (1.7) will return the window object inside the iframe with oIFrame.contentWindow.
  • Safari (1.2.4) doesn't understand that property, but does have oIframe.contentDocument, which points to the document object inside the iframe.
  • To make it even more complicated, Opera 7 uses oIframe.contentDocument, but it points to the window object of the iframe. Because Safari has no way to directly access the window object of an iframe element via standard DOM (or does it?), our fully modern-cross-browser-compatible code will only be able to access the document within the iframe.

Can't find @Nullable inside javax.annotation.*

The artifact has been moved from net.sourceforge.findbugs to

<dependency>
    <groupId>com.google.code.findbugs</groupId>
    <artifactId>jsr305</artifactId>
    <version>3.0.0</version>
</dependency>

Username and password in https url

When you put the username and password in front of the host, this data is not sent that way to the server. It is instead transformed to a request header depending on the authentication schema used. Most of the time this is going to be Basic Auth which I describe below. A similar (but significantly less often used) authentication scheme is Digest Auth which nowadays provides comparable security features.

With Basic Auth, the HTTP request from the question will look something like this:

GET / HTTP/1.1
Host: example.com
Authorization: Basic Zm9vOnBhc3N3b3Jk

The hash like string you see there is created by the browser like this: base64_encode(username + ":" + password).

To outsiders of the HTTPS transfer, this information is hidden (as everything else on the HTTP level). You should take care of logging on the client and all intermediate servers though. The username will normally be shown in server logs, but the password won't. This is not guaranteed though. When you call that URL on the client with e.g. curl, the username and password will be clearly visible on the process list and might turn up in the bash history file.

When you send passwords in a GET request as e.g. http://example.com/login.php?username=me&password=secure the username and password will always turn up in server logs of your webserver, application server, caches, ... unless you specifically configure your servers to not log it. This only applies to servers being able to read the unencrypted http data, like your application server or any middleboxes such as loadbalancers, CDNs, proxies, etc. though.

Basic auth is standardized and implemented by browsers by showing this little username/password popup you might have seen already. When you put the username/password into an HTML form sent via GET or POST, you have to implement all the login/logout logic yourself (which might be an advantage and allows you to more control over the login/logout flow for the added "cost" of having to implement this securely again). But you should never transfer usernames and passwords by GET parameters. If you have to, use POST instead. The prevents the logging of this data by default.

When implementing an authentication mechanism with a user/password entry form and a subsequent cookie-based session as it is commonly used today, you have to make sure that the password is either transported with POST requests or one of the standardized authentication schemes above only.

Concluding I could say, that transfering data that way over HTTPS is likely safe, as long as you take care that the password does not turn up in unexpected places. But that advice applies to every transfer of any password in any way.

How do I cast a JSON Object to a TypeScript class?

You can cast json to property like this

class Jobs {
  constructor(JSONdata) {
    this.HEAT = JSONdata.HEAT;    
    this.HEAT_EAF = JSONdata.HEAT_EAF;    
  }
  
}

 var job = new Jobs({HEAT:'123',HEAT_EAF:'456'});

Using a remote repository with non-standard port

SSH doesn't use the : syntax when specifying a port. The easiest way to do this is to edit your ~/.ssh/config file and add:

Host git.host.de
  Port 4019

Then specify just git.host.de without a port number.

iPhone X / 8 / 8 Plus CSS media queries

It seems that the most accurate (and seamless) method of adding the padding for iPhone X/8 using env()...

padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);

Here's a link describing this:

https://css-tricks.com/the-notch-and-css/

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

I'm turning my comment to an answer, so it can be accepted and this question no longer remains unanswered.

The most likely cause of this is a malformed response, which includes characters before the initial <?xml …>. So please have a look at the document as transferred over HTTP, and fix this on the server side.

Gradle sync failed: failed to find Build Tools revision 24.0.0 rc1

faced the same problem: Gradle sync failed: failed to find Build Tools revision x.x.x

reason: the build tools for that version was not down loaded properly solution:

  1. Click File > Settings (on a Mac, Android Studio > Preferences) to open the Settings dialog.
  2. Go to Appearance & Behavior > System Settings > Android SDK (Or simply search for Android SDK on the search bar)
  3. Go to SDK Tools tab > Check the Show Package Details checkbox
  4. uncheck the specific version to remove it.
  5. click apply.

then follow the steps 1 to 3 and 6.

  1. Select the specific version of the build tool and click on the Apply button After the installation, sync the project

Bootstrap 4 multiselect dropdown

Because the bootstrap-select is a bootstrap component and therefore you need to include it in your code as you did for your V3

NOTE: this component only works in since version 1.13.0

_x000D_
_x000D_
$('select').selectpicker();
_x000D_
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css">_x000D_
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.13.1/css/bootstrap-select.css" />_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.bundle.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.13.1/js/bootstrap-select.min.js"></script>_x000D_
_x000D_
_x000D_
_x000D_
<select class="selectpicker" multiple data-live-search="true">_x000D_
  <option>Mustard</option>_x000D_
  <option>Ketchup</option>_x000D_
  <option>Relish</option>_x000D_
</select>
_x000D_
_x000D_
_x000D_

How to save password when using Subversion from the console

It depends on the protocol you're using. If you're using SVN + SSH, the SVN client can't save your password because it never touches it - the SSH client prompts you for it directly. In this case, you can use an SSH key and ssh-agent to avoid the constant prompts. If you're using the svnserve protocol or HTTP(S), then the SSH client is handling your password and can save it.

MSSQL Select statement with incremental integer column... not from a table

Try ROW_NUMBER()

http://msdn.microsoft.com/en-us/library/ms186734.aspx

Example:

SELECT
  col1,
  col2,
  ROW_NUMBER() OVER (ORDER BY col1) AS rownum
FROM tbl

Detect network connection type on Android

Detect the what type of network and getting the boolean value of isconnected or not use below snippet

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.telephony.TelephonyManager;
public class NetworkManagerUtils {

/**
 * Get the network info
 * @param context
 * @return
 */
public static NetworkInfo getNetworkInfo(Context context){
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    return cm.getActiveNetworkInfo();
}

/**
 * Check if there is any connectivity
 * @param context
 * @return
 */
public static boolean isConnected(Context context){
    NetworkInfo info = NetworkManagerUtils.getNetworkInfo(context);
    return (info != null && info.isConnected());
}

/**
 * Check if there is any connectivity to a Wifi network
 * @param context.
 * @param type
 * @return
 */
public static boolean isConnectedWifi(Context context){
    NetworkInfo info = NetworkManagerUtils.getNetworkInfo(context);
    return (info != null && info.isConnected() && info.getType() == ConnectivityManager.TYPE_WIFI);
}

/**
 * Check if there is any connectivity to a mobile network
 * @param context
 * @param type
 * @return
 */
public static boolean isConnectedMobile(Context context){
    NetworkInfo info = NetworkManagerUtils.getNetworkInfo(context);
    return (info != null && info.isConnected() && info.getType() == ConnectivityManager.TYPE_MOBILE);
}

/**
 * Check if there is fast connectivity
 * @param context
 * @return
 */
public static boolean isConnectedFast(Context context){
    NetworkInfo info = NetworkManagerUtils.getNetworkInfo(context);
    return (info != null && info.isConnected() && NetworkManagerUtils.isConnectionFast(info.getType(),info.getSubtype()));
}

/**
 * Check if the connection is fast
 * @param type
 * @param subType
 * @return
 */
public static boolean isConnectionFast(int type, int subType){
    if(type== ConnectivityManager.TYPE_WIFI){
        return true;
    }else if(type==ConnectivityManager.TYPE_MOBILE){
        switch(subType){
            case TelephonyManager.NETWORK_TYPE_1xRTT:
                return false; // ~ 50-100 kbps
            case TelephonyManager.NETWORK_TYPE_CDMA:
                return false; // ~ 14-64 kbps
            case TelephonyManager.NETWORK_TYPE_EDGE:
                return false; // ~ 50-100 kbps
            case TelephonyManager.NETWORK_TYPE_EVDO_0:
                return true; // ~ 400-1000 kbps
            case TelephonyManager.NETWORK_TYPE_EVDO_A:
                return true; // ~ 600-1400 kbps
            case TelephonyManager.NETWORK_TYPE_GPRS:
                return false; // ~ 100 kbps
            case TelephonyManager.NETWORK_TYPE_HSDPA:
                return true; // ~ 2-14 Mbps
            case TelephonyManager.NETWORK_TYPE_HSPA:
                return true; // ~ 700-1700 kbps
            case TelephonyManager.NETWORK_TYPE_HSUPA:
                return true; // ~ 1-23 Mbps
            case TelephonyManager.NETWORK_TYPE_UMTS:
                return true; // ~ 400-7000 kbps
            /*
             * Above API level 7, make sure to set android:targetSdkVersion
             * to appropriate level to use these
             */
            case TelephonyManager.NETWORK_TYPE_EHRPD: // API level 11
                return true; // ~ 1-2 Mbps
            case TelephonyManager.NETWORK_TYPE_EVDO_B: // API level 9
                return true; // ~ 5 Mbps
            case TelephonyManager.NETWORK_TYPE_HSPAP: // API level 13
                return true; // ~ 10-20 Mbps
            case TelephonyManager.NETWORK_TYPE_IDEN: // API level 8
                return false; // ~25 kbps
            case TelephonyManager.NETWORK_TYPE_LTE: // API level 11
                return true; // ~ 10+ Mbps
            // Unknown
            case TelephonyManager.NETWORK_TYPE_UNKNOWN:
            default:
                return false;
        }
    }else{
        return false;
    }
}
public static String getNetworkClass(Context context) {
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo info = cm.getActiveNetworkInfo();
    if (info == null || !info.isConnected())
        return "-"; // not connected
    if (info.getType() == ConnectivityManager.TYPE_WIFI)
        return "WIFI";
    if (info.getType() == ConnectivityManager.TYPE_MOBILE) {
        int networkType = info.getSubtype();
        switch (networkType) {
            case TelephonyManager.NETWORK_TYPE_GPRS:
            case TelephonyManager.NETWORK_TYPE_EDGE:
            case TelephonyManager.NETWORK_TYPE_CDMA:
            case TelephonyManager.NETWORK_TYPE_1xRTT:
            case TelephonyManager.NETWORK_TYPE_IDEN:     // api< 8: replace by 11
            case TelephonyManager.NETWORK_TYPE_GSM:      // api<25: replace by 16
                return "2G";
            case TelephonyManager.NETWORK_TYPE_UMTS:
            case TelephonyManager.NETWORK_TYPE_EVDO_0:
            case TelephonyManager.NETWORK_TYPE_EVDO_A:
            case TelephonyManager.NETWORK_TYPE_HSDPA:
            case TelephonyManager.NETWORK_TYPE_HSUPA:
            case TelephonyManager.NETWORK_TYPE_HSPA:
            case TelephonyManager.NETWORK_TYPE_EVDO_B:   // api< 9: replace by 12
            case TelephonyManager.NETWORK_TYPE_EHRPD:    // api<11: replace by 14
            case TelephonyManager.NETWORK_TYPE_HSPAP:    // api<13: replace by 15
            case TelephonyManager.NETWORK_TYPE_TD_SCDMA: // api<25: replace by 17
                return "3G";
            case TelephonyManager.NETWORK_TYPE_LTE:      // api<11: replace by 13
            case TelephonyManager.NETWORK_TYPE_IWLAN:    // api<25: replace by 18
            case 19: // LTE_CA
                return "4G";
            default:
                return "?";
        }
    }
    return "?";
}
}

use this following the class pass the context you will the get network status like network type,fast network,etc.

Purpose of installing Twitter Bootstrap through npm?

  1. The point of using CDN is that it is faster, first of all, because it is a distributed network, but secondly, because the static files are being cached by the browsers and chances are high that, for example, the CDN's jquery library that your site uses had already been downloaded by the user's browser, and therefore the file had been cached, and therefore no unnecessary download is taking place. That being said, it is still a good idea to provide a fallback.

    Now, the point of bootstrap's npm package

    is that it provides bootstrap's javascript file as a module. As has been mentioned above, this makes it possible to require it using browserify, which is the most likely use case and, as I understand it, the main reason for bootstrap being published on npm.

  2. How to use it

    Imagine the following project structure:

    project
    |-- node_modules
    |-- public
    |   |-- css
    |   |-- img
    |   |-- js
    |   |-- index.html
    |-- package.json
    
    

In your index.html you can reference both css and js files like this:

<link rel="stylesheet" href="../node_modules/bootstrap/dist/css/bootstrap.min.css">
<script src="../node_modules/bootstrap/dist/js/bootstrap.min.js"></script>

Which is the simplest way, and correct for the .css files. But it is much better to include the bootstrap.js file like this somewhere in your public/js/*.js files:

var bootstrap = require('bootstrap');

And you include this code only in those javascript files where you actually need bootstrap.js. Browserify takes care of including this file for you.

Now, the drawback is that you now have your front-end files as node_modules dependencies, and the node_modules folder is usually not checked in with git. I think this is the most controversial part, with many opinions and solutions.


UPDATE March 2017

Almost two years have passed since I wrote this answer and an update is in place.

Now the generally accepted way is to use a bundler like webpack (or another bundler of choice) to bundle all your assets in a build step.

Firstly, it allows you to use commonjs syntax just like browserify, so to include bootstrap js code in your project you do the same:

const bootstrap = require('bootstrap');

As for the css files, webpack has so called "loaders". They allow you write this in your js code:

require('bootstrap/dist/css/bootstrap.css');

and the css files will be "magically" included in your build. They will be dynamically added as <style /> tags when your app runs, but you can configure webpack to export them as a separate css file. You can read more about that in webpack's documentation.

In conclusion.

  1. You should "bundle" your app code with a bundler
  2. You shouldn't commit neither node_modules nor the dynamically built files to git. You can add a build script to npm which should be used to deploy files on server. Anyway, this can be done in different ways depending on your preferred build process.

Undefined symbols for architecture x86_64 on Xcode 6.1

I just had this error when I opened a (quite) old project, created in Xcode 4~ish, in Xcode 6.4. While the linked Frameworks were visible in the Project sidebar, I overlooked that there were no linked libraries in the Target Build Phases tab. Once I fixed that, it compiled fine.

Running multiple AsyncTasks at the same time -- not possible?

AsyncTask uses a thread pool pattern for running the stuff from doInBackground(). The issue is initially (in early Android OS versions) the pool size was just 1, meaning no parallel computations for a bunch of AsyncTasks. But later they fixed that and now the size is 5, so at most 5 AsyncTasks can run simultaneously. Unfortunately I don't remember in what version exactly they changed that.

UPDATE:

Here is what current (2012-01-27) API says on this:

When first introduced, AsyncTasks were executed serially on a single background thread. Starting with DONUT, this was changed to a pool of threads allowing multiple tasks to operate in parallel. After HONEYCOMB, it is planned to change this back to a single thread to avoid common application errors caused by parallel execution. If you truly want parallel execution, you can use the executeOnExecutor(Executor, Params...) version of this method with THREAD_POOL_EXECUTOR; however, see commentary there for warnings on its use.

DONUT is Android 1.6, HONEYCOMB is Android 3.0.

UPDATE: 2

See the comment by kabuko from Mar 7 2012 at 1:27.

It turns out that for APIs where "a pool of threads allowing multiple tasks to operate in parallel" is used (starting from 1.6 and ending on 3.0) the number of simultaneously running AsyncTasks depends on how many tasks have been passed for execution already, but have not finished their doInBackground() yet.

This is tested/confirmed by me on 2.2. Suppose you have a custom AsyncTask that just sleeps a second in doInBackground(). AsyncTasks use a fixed size queue internally for storing delayed tasks. Queue size is 10 by default. If you start 15 your custom tasks in a row, then first 5 will enter their doInBackground(), but the rest will wait in a queue for a free worker thread. As soon as any of the first 5 finishes, and thus releases a worker thread, a task from the queue will start execution. So in this case at most 5 tasks will run simultaneously. However if you start 16 your custom tasks in a row, then first 5 will enter their doInBackground(), the rest 10 will get into the queue, but for the 16th a new worker thread will be created so it'll start execution immediately. So in this case at most 6 tasks will run simultaneously.

There is a limit of how many tasks can be run simultaneously. Since AsyncTask uses a thread pool executor with limited max number of worker threads (128) and the delayed tasks queue has fixed size 10, if you try to execute more than 138 your custom tasks the app will crash with java.util.concurrent.RejectedExecutionException.

Starting from 3.0 the API allows to use your custom thread pool executor via AsyncTask.executeOnExecutor(Executor exec, Params... params) method. This allows, for instance, to configure the size of the delayed tasks queue if default 10 is not what you need.

As @Knossos mentions, there is an option to use AsyncTaskCompat.executeParallel(task, params); from support v.4 library to run tasks in parallel without bothering with API level. This method became deprecated in API level 26.0.0.

UPDATE: 3

Here is a simple test app to play with number of tasks, serial vs. parallel execution: https://github.com/vitkhudenko/test_asynctask

UPDATE: 4 (thanks @penkzhou for pointing this out)

Starting from Android 4.4 AsyncTask behaves differently from what was described in UPDATE: 2 section. There is a fix to prevent AsyncTask from creating too many threads.

Before Android 4.4 (API 19) AsyncTask had the following fields:

private static final int CORE_POOL_SIZE = 5;
private static final int MAXIMUM_POOL_SIZE = 128;
private static final BlockingQueue<Runnable> sPoolWorkQueue =
        new LinkedBlockingQueue<Runnable>(10);

In Android 4.4 (API 19) the above fields are changed to this:

private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
private static final int CORE_POOL_SIZE = CPU_COUNT + 1;
private static final int MAXIMUM_POOL_SIZE = CPU_COUNT * 2 + 1;
private static final BlockingQueue<Runnable> sPoolWorkQueue =
        new LinkedBlockingQueue<Runnable>(128);

This change increases the size of the queue to 128 items and reduces the maximum number of threads to the number of CPU cores * 2 + 1. Apps can still submit the same number of tasks.

Turn off iPhone/Safari input element rounding

For me on iOS 5.1.1 on a iPhone 3GS I had to clear the styling of a search field and the set it to the style intended

input[type="search"] {-webkit-appearance: none; border-radius: 0 3px 3px 0;}

Doing -webkit-border-radius: 0; alone did not clear the native styling. This was also for a webview on a native app.

javac not working in windows command prompt

for /d %i in ("\Program Files\Java\jdk*") do set JAVA_HOME=%i
set JAVA_HOME

this solution worked to me

postgresql: INSERT INTO ... (SELECT * ...)

Here's an alternate solution, without using dblink.

Suppose B represents the source database and A represents the target database: Then,

  1. Copy table from source DB to target DB:

    pg_dump -t <source_table> <source_db> | psql <target_db>
    
  2. Open psql prompt, connect to target_db, and use a simple insert:

    psql
    # \c <target_db>;
    # INSERT INTO <target_table>(id, x, y) SELECT id, x, y FROM <source_table>;
    
  3. At the end, delete the copy of source_table that you created in target_table.

    # DROP TABLE <source_table>;
    

Convert blob to base64

this worked for me:

var blobToBase64 = function(blob, callback) {
    var reader = new FileReader();
    reader.onload = function() {
        var dataUrl = reader.result;
        var base64 = dataUrl.split(',')[1];
        callback(base64);
    };
    reader.readAsDataURL(blob);
};

Alter a MySQL column to be AUTO_INCREMENT

alter table tbl_user MODIFY COLUMN id int(10) auto_increment;

How to filter for multiple criteria in Excel?

You can pass an array as the first AutoFilter argument and use the xlFilterValues operator.

This will display PDF, DOC and DOCX filetypes.

Criteria1:=Array(".pdf", ".doc", ".docx"), Operator:=xlFilterValues

The response content cannot be parsed because the Internet Explorer engine is not available, or

It is sure because the Invoke-WebRequest command has a dependency on the Internet Explorer assemblies and are invoking it to parse the result as per default behaviour. As Matt suggest, you can simply launch IE and make your selection in the settings prompt which is popping up at first launch. And the error you experience will disappear.

But this is only possible if you run your powershell scripts as the same windows user as whom you launched the IE with. The IE settings are stored under your current windows profile. So if you, like me run your task in a scheduler on a server as the SYSTEM user, this will not work.

So here you will have to change your scripts and add the -UseBasicParsing argument, as ijn this example: $WebResponse = Invoke-WebRequest -Uri $url -TimeoutSec 1800 -ErrorAction:Stop -Method:Post -Headers $headers -UseBasicParsing

Bash conditionals: how to "and" expressions? (if [ ! -z $VAR && -e $VAR ])

if [ -n "$var" -a -e "$var" ]; then
    do something ...
fi

 

How do I generate a SALT in Java for Salted-Hash?

You were right regarding how you want to generate salt i.e. its nothing but a random number. For this particular case it would protect your system from possible Dictionary attacks. Now, for the second problem what you could do is instead of using UTF-8 encoding you may want to use Base64. Here, is a sample for generating a hash. I am using Apache Common Codecs for doing the base64 encoding you may select one of your own

public byte[] generateSalt() {
        SecureRandom random = new SecureRandom();
        byte bytes[] = new byte[20];
        random.nextBytes(bytes);
        return bytes;
    }

public String bytetoString(byte[] input) {
        return org.apache.commons.codec.binary.Base64.encodeBase64String(input);
    }

public byte[] getHashWithSalt(String input, HashingTechqniue technique, byte[] salt) throws NoSuchAlgorithmException {
        MessageDigest digest = MessageDigest.getInstance(technique.value);
        digest.reset();
        digest.update(salt);
        byte[] hashedBytes = digest.digest(stringToByte(input));
        return hashedBytes;
    }
public byte[] stringToByte(String input) {
        if (Base64.isBase64(input)) {
            return Base64.decodeBase64(input);

        } else {
            return Base64.encodeBase64(input.getBytes());
        }
    }

Here is some additional reference of the standard practice in password hashing directly from OWASP

Sending a file over TCP sockets in Python

You can send some flag to stop while loop in server

for example

Server side:

import socket
s = socket.socket()
s.bind(("localhost", 5000))
s.listen(1)
c,a = s.accept()
filetodown = open("img.png", "wb")
while True:
   print("Receiving....")
   data = c.recv(1024)
   if data == b"DONE":
           print("Done Receiving.")
           break
   filetodown.write(data)
filetodown.close()
c.send("Thank you for connecting.")
c.shutdown(2)
c.close()
s.close()
#Done :)

Client side:

import socket
s = socket.socket()
s.connect(("localhost", 5000))
filetosend = open("img.png", "rb")
data = filetosend.read(1024)
while data:
    print("Sending...")
    s.send(data)
    data = filetosend.read(1024)
filetosend.close()
s.send(b"DONE")
print("Done Sending.")
print(s.recv(1024))
s.shutdown(2)
s.close()
#Done :)

What is the reason and how to avoid the [FIN, ACK] , [RST] and [RST, ACK]

Here is a rough explanation of the concepts.

[ACK] is the acknowledgement that the previously sent data packet was received.

[FIN] is sent by a host when it wants to terminate the connection; the TCP protocol requires both endpoints to send the termination request (i.e. FIN).

So, suppose

  • host A sends a data packet to host B
  • and then host B wants to close the connection.
  • Host B (depending on timing) can respond with [FIN,ACK] indicating that it received the sent packet and wants to close the session.
  • Host A should then respond with a [FIN,ACK] indicating that it received the termination request (the ACK part) and that it too will close the connection (the FIN part).

However, if host A wants to close the session after sending the packet, it would only send a [FIN] packet (nothing to acknowledge) but host B would respond with [FIN,ACK] (acknowledges the request and responds with FIN).

Finally, some TCP stacks perform half-duplex termination, meaning that they can send [RST] instead of the usual [FIN,ACK]. This happens when the host actively closes the session without processing all the data that was sent to it. Linux is one operating system which does just this.

You can find a more detailed and comprehensive explanation here.

How to use the IEqualityComparer

Try This code:

public class GenericCompare<T> : IEqualityComparer<T> where T : class
{
    private Func<T, object> _expr { get; set; }
    public GenericCompare(Func<T, object> expr)
    {
        this._expr = expr;
    }
    public bool Equals(T x, T y)
    {
        var first = _expr.Invoke(x);
        var sec = _expr.Invoke(y);
        if (first != null && first.Equals(sec))
            return true;
        else
            return false;
    }
    public int GetHashCode(T obj)
    {
        return obj.GetHashCode();
    }
}

Example of its use would be

collection = collection
    .Except(ExistedDataEles, new GenericCompare<DataEle>(x=>x.Id))
    .ToList(); 

How to do INSERT into a table records extracted from another table

You have two syntax options:

Option 1

CREATE TABLE Table1 (
    id int identity(1, 1) not null,
    LongIntColumn1 int,
    CurrencyColumn money
)

CREATE TABLE Table2 (
    id int identity(1, 1) not null,
    LongIntColumn2 int,
    CurrencyColumn2 money
)

INSERT INTO Table1 VALUES(12, 12.00)
INSERT INTO Table1 VALUES(11, 13.00)

INSERT INTO Table2
SELECT LongIntColumn1, Avg(CurrencyColumn) as CurrencyColumn1 FROM Table1 GROUP BY LongIntColumn1

Option 2

CREATE TABLE Table1 (
    id int identity(1, 1) not null,
    LongIntColumn1 int,
    CurrencyColumn money
)

INSERT INTO Table1 VALUES(12, 12.00)
INSERT INTO Table1 VALUES(11, 13.00)


SELECT LongIntColumn1, Avg(CurrencyColumn) as CurrencyColumn1
INTO Table2
FROM Table1
GROUP BY LongIntColumn1

Bear in mind that Option 2 will create a table with only the columns on the projection (those on the SELECT).

Daemon Threads Explanation

Some threads do background tasks, like sending keepalive packets, or performing periodic garbage collection, or whatever. These are only useful when the main program is running, and it's okay to kill them off once the other, non-daemon, threads have exited.

Without daemon threads, you'd have to keep track of them, and tell them to exit, before your program can completely quit. By setting them as daemon threads, you can let them run and forget about them, and when your program quits, any daemon threads are killed automatically.

PowerShell: Store Entire Text File Contents in Variable

One more approach to reading a file that I happen to like is referred to variously as variable notation or variable syntax and involves simply enclosing a filespec within curly braces preceded by a dollar sign, to wit:

$content = ${C:file.txt}

This notation may be used as either an L-value or an R-value; thus, you could just as easily write to a file with something like this:

 ${D:\path\to\file.txt} = $content

Another handy use is that you can modify a file in place without a temporary file and without sub-expressions, for example:

${C:file.txt} = ${C:file.txt} | select -skip 1

I became fascinated by this notation initially because it was very difficult to find out anything about it! Even the PowerShell 2.0 specification mentions it only once showing just one line using it--but with no explanation or details of use at all. I have subsequently found this blog entry on PowerShell variables that gives some good insights.

One final note on using this: you must use a drive designation, i.e. ${drive:filespec} as I have done in all the examples above. Without the drive (e.g. ${file.txt}) it does not work. No restrictions on the filespec on that drive: it may be absolute or relative.

Detect encoding and make everything UTF-8

This cheatsheet lists some common caveats related to UTF-8 handling in PHP: http://developer.loftdigital.com/blog/php-utf-8-cheatsheet

This function detecting multibyte characters in a string might also prove helpful (source):


function detectUTF8($string)
{
    return preg_match('%(?:
        [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
        |\xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
        |[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2} # straight 3-byte
        |\xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
        |\xF0[\x90-\xBF][\x80-\xBF]{2}     # planes 1-3
        |[\xF1-\xF3][\x80-\xBF]{3}         # planes 4-15
        |\xF4[\x80-\x8F][\x80-\xBF]{2}     # plane 16
        )+%xs', 
    $string);
}

Change the mouse cursor on mouse over to anchor-like style

If you want to do this in jQuery instead of CSS, you basically follow the same process.

Assuming you have some <div id="target"></div>, you can use the following code:

$("#target").hover(function() {
    $(this).css('cursor','pointer');
}, function() {
    $(this).css('cursor','auto');
});

and that should do it.

"Data too long for column" - why?

Varchar has its own limits. Maybe try changing datatype to text.!

Check if decimal value is null

decimal is a value type in .NET. And value types can't be null. But if you use nullable type for your decimal, then you can check your decimal is null or not. Like myDecimal?

Nullable types are instances of the System.Nullable struct. A nullable type can represent the normal range of values for its underlying value type, plus an additional null value.

if (myDecimal.HasValue)

But I think in your database, if this column contains nullable values, then it shouldn't be type of decimal.

How do I add a auto_increment primary key in SQL Server database?

If you have the column it's very easy.

Using the designer, you could set the column as an identity (1,1): right click on the table ? design ? in part left (right click) ? properties ? in identity columns, select #column.


Properties:

enter image description here

Identity column:

enter image description here

What's the best way to cancel event propagation between nested ng-click calls?

Sometimes, it may make most sense just to do this:

<widget ng-click="myClickHandler(); $event.stopPropagation()"/>

I chose to do it this way because I didn't want myClickHandler() to stop the event propagation in the many other places it was used.

Sure, I could've added a boolean parameter to the handler function, but stopPropagation() is much more meaningful than just true.

Why does javascript map function return undefined?

Since ES6 filter supports pointy arrow notation (like LINQ):

So it can be boiled down to following one-liner.

['a','b',1].filter(item => typeof item ==='string');

Convert Select Columns in Pandas Dataframe to Numpy Array

The fastest and easiest way is to use .as_matrix(). One short line:

df.iloc[:,[1,2,3]].as_matrix()

Gives:

array([[3, 2, 0.816497],
   [0, 'NaN', 'NaN'],
   [2, 51, 50.0]], dtype=object)

By using indices of the columns, you can use this code for any dataframe with different column names.

Here are the steps for your example:

import pandas as pd
columns = ['viz', 'a1_count', 'a1_mean', 'a1_std']
index = [0,1,2]
vals = {'viz': ['n','n','n'], 'a1_count': [3,0,2], 'a1_mean': [2,'NaN', 51], 'a1_std': [0.816497, 'NaN', 50.000000]}
df = pd.DataFrame(vals, columns=columns, index=index)

Gives:

   viz  a1_count a1_mean    a1_std
0   n         3       2  0.816497
1   n         0     NaN       NaN
2   n         2      51        50

Then:

x1 = df.iloc[:,[1,2,3]].as_matrix()

Gives:

array([[3, 2, 0.816497],
   [0, 'NaN', 'NaN'],
   [2, 51, 50.0]], dtype=object)

Where x1 is numpy.ndarray.

What is newline character -- '\n'

Try this:

$ sed -e $'s/\n/\n\n/g' states

How to get a variable from a file to another file in Node.js

You need module.exports:

Exports

An object which is shared between all instances of the current module and made accessible through require(). exports is the same as the module.exports object. See src/node.js for more information. exports isn't actually a global but rather local to each module.

For example, if you would like to expose variableName with value "variableValue" on sourceFile.js then you can either set the entire exports as such:

module.exports = { variableName: "variableValue" };

Or you can set the individual value with:

module.exports.variableName = "variableValue";

To consume that value in another file, you need to require(...) it first (with relative pathing):

const sourceFile = require('./sourceFile');
console.log(sourceFile.variableName);

Alternatively, you can deconstruct it.

const { variableName } = require('./sourceFile');
//            current directory --^
// ../     would be one directory down
// ../../  is two directories down

If all you want out of the file is variableName then

./sourceFile.js:

const variableName = 'variableValue'
module.exports = variableName

./consumer.js:

const variableName = require('./sourceFile')

Edit (2020):

Since Node.js version 8.9.0, you can also use ECMAScript Modules with varying levels of support. The documentation.

  • For Node v13.9.0 and beyond, experimental modules are enabled by default
  • For versions of Node less than version 13.9.0, use --experimental-modules

Node.js will treat the following as ES modules when passed to node as the initial input, or when referenced by import statements within ES module code:

  • Files ending in .mjs.
  • Files ending in .js when the nearest parent package.json file contains a top-level field "type" with a value of "module".
  • Strings passed in as an argument to --eval or --print, or piped to node via STDIN, with the flag --input-type=module.

Once you have it setup, you can use import and export.

Using the example above, there are two approaches you can take

./sourceFile.js:

// This is a named export of variableName
export const variableName = 'variableValue'
// Alternatively, you could have exported it as a default. 
// For sake of explanation, I'm wrapping the variable in an object
// but it is not necessary. 
// You can actually omit declaring what variableName is here. 
// { variableName } is equivalent to { variableName: variableName } in this case. 
export default { variableName: variableName } 

./consumer.js:

// There are three ways of importing. 
// If you need access to a non-default export, then 
// you use { nameOfExportedVariable } 
import { variableName } from './sourceFile'
console.log(variableName) // 'variableValue'

// Otherwise, you simply provide a local variable name 
// for what was exported as default.
import sourceFile from './sourceFile'
console.log(sourceFile.variableName) // 'variableValue'

./sourceFileWithoutDefault.js:

// The third way of importing is for situations where there
// isn't a default export but you want to warehouse everything
// under a single variable. Say you have:
export const a = 'A'
export const b = 'B'

./consumer2.js

// Then you can import all exports under a single variable
// with the usage of * as:
import * as sourceFileWithoutDefault from './sourceFileWithoutDefault'

console.log(sourceFileWithoutDefault.a) // 'A'
console.log(sourceFileWithoutDefault.b) // 'B'

// You can use this approach even if there is a default export:
import * as sourceFile from './sourceFile'

// Default exports are under the variable default:
console.log(sourceFile.default) // { variableName: 'variableValue' }

// As well as named exports:
console.log(sourceFile.variableName) // 'variableValue

Where to place the 'assets' folder in Android Studio?

In Android Studio 4.1.1

Right Click on your module (app for example) -> New -> Folder -> Assets Folder

enter image description here

Overriding css style?

You just have to reset the values you don't want to their defaults. No need to get into a mess by using !important.

#zoomTarget .slikezamenjanje img {
    max-height: auto;
    padding-right: 0px;
}

Hatting

I think the key datum you are missing is that CSS comes with default values. If you want to override a value, set it back to its default, which you can look up.

For example, all CSS height and width attributes default to auto.

Angular2 dynamic change CSS property

1) Using inline styles

<div [style.color]="myDynamicColor">

2) Use multiple CSS classes mapping to what you want and switch classes like:

 /* CSS */
 .theme { /* any shared styles */ }
 .theme.blue { color: blue; }
 .theme.red { color: red; }

 /* Template */
 <div class="theme" [ngClass]="{blue: isBlue, red: isRed}">
 <div class="theme" [class.blue]="isBlue">

Code samples from: https://angular.io/cheatsheet

More info on ngClass directive : https://angular.io/docs/ts/latest/api/common/index/NgClass-directive.html

Firefox 'Cross-Origin Request Blocked' despite headers

I've found solution after 2 days :(.

Important note: when responding to a credentialed request, server must specify a domain, and cannot use wild carding.

https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Requests_with_credentials

get current date with 'yyyy-MM-dd' format in Angular 4

You can use DatePipe for formatting Date in Angular.

In ts if you want to format date then you can inject DatePipe as Service in constructor like this

import { DatePipe } from '@angular/common';

@Component({
    templateUrl: './name.component.html',
    styleUrls: ['./name.component.scss'],
    providers: [DatePipe]
})

myDate = new Date();
constructor(private datePipe: DatePipe){
    this.myDate = this.datePipe.transform(this.myDate, 'yyyy-MM-dd');
}

And if you want to format in html file, 'Shortdate' will return date of type MM/DD/YY

{{myDate | date: 'shortDate' }}

As of Angular 6, this also works,

import {formatDate} from '@angular/common';

formatDate(new Date(), 'yyyy/MM/dd', 'en');

Wi-Fi Direct and iOS Support

It took me a while to find out what is going on, but here is the summary. I hope this save people a lot of time.

Apple are not playing nice with Wi-Fi Direct, not in the same way that Android is. The Multipeer Connectivity Framework that Apple provides combines both BLE and WiFi Direct together and will only work with Apple devices and not any device that is using Wi-Fi Direct.

https://developer.apple.com/library/ios/documentation/MultipeerConnectivity/Reference/MultipeerConnectivityFramework/index.html

It states the following in this documentation - "The Multipeer Connectivity framework provides support for discovering services provided by nearby iOS devices using infrastructure Wi-Fi networks, peer-to-peer Wi-Fi, and Bluetooth personal area networks and subsequently communicating with those services by sending message-based data, streaming data, and resources (such as files)."

Additionally, Wi-Fi direct in this mode between i-Devices will need iPhone 5 and above.

There are apps that use a form of Wi-Fi Direct on the App Store, but these are using their own libraries.

To get specific part of a string in c#

Something like this?

string b = a.Split(',')[0];

Difference between using Throwable and Exception in a try catch

Thowable catches really everything even ThreadDeath which gets thrown by default to stop a thread from the now deprecated Thread.stop() method. So by catching Throwable you can be sure that you'll never leave the try block without at least going through your catch block, but you should be prepared to also handle OutOfMemoryError and InternalError or StackOverflowError.

Catching Throwable is most useful for outer server loops that delegate all sorts of requests to outside code but may itself never terminate to keep the service alive.

How to add items to array in nodejs

var array = [];

//length array now = 0
array[array.length] = 'hello';
//length array now = 1
//            0
//array = ['hello'];//length = 1

Add new field to every document in a MongoDB collection

Same as the updating existing collection field, $set will add a new fields if the specified field does not exist.

Check out this example:

> db.foo.find()
> db.foo.insert({"test":"a"})
> db.foo.find()
{ "_id" : ObjectId("4e93037bbf6f1dd3a0a9541a"), "test" : "a" }
> item = db.foo.findOne()
{ "_id" : ObjectId("4e93037bbf6f1dd3a0a9541a"), "test" : "a" }
> db.foo.update({"_id" :ObjectId("4e93037bbf6f1dd3a0a9541a") },{$set : {"new_field":1}})
> db.foo.find()
{ "_id" : ObjectId("4e93037bbf6f1dd3a0a9541a"), "new_field" : 1, "test" : "a" }

EDIT:

In case you want to add a new_field to all your collection, you have to use empty selector, and set multi flag to true (last param) to update all the documents

db.your_collection.update(
  {},
  { $set: {"new_field": 1} },
  false,
  true
)

EDIT:

In the above example last 2 fields false, true specifies the upsert and multi flags.

Upsert: If set to true, creates a new document when no document matches the query criteria.

Multi: If set to true, updates multiple documents that meet the query criteria. If set to false, updates one document.

This is for Mongo versions prior to 2.2. For latest versions the query is changed a bit

db.your_collection.update({},
                          {$set : {"new_field":1}},
                          {upsert:false,
                          multi:true}) 

Can't get Python to import from a different folder

import user

u=user.User() #error on this line

Because of the lack of __init__ mentioned above, you would expect an ImportError which would make the problem clearer.

You don't get one because 'user' is also an existing module in the standard library. Your import statement grabs that one and tries to find the User class inside it; that doesn't exist and only then do you get the error.

It is generally a good idea to make your import absolute:

import Server.Models.user

to avoid this kind of ambiguity. Indeed from Python 2.7 'import user' won't look relative to the current module at all.

If you really want relative imports, you can have them explicitly in Python 2.5 and up using the somewhat ugly syntax:

from .user import User

How do I auto-resize an image to fit a 'div' container?

Give the height and width you need for your image to the div that contains the <img> tag. Don't forget to give the height/width in the proper style tag.

In the <img> tag, give the max-height and max-width as 100%.

<div style="height:750px; width:700px;">
    <img alt="That Image" style="max-height:100%; max-width:100%;" src="">
</div>

You can add the details in the appropriate classes after you get it right.

"call to undefined function" error when calling class method

You dont have a function named assign(), but a method with this name. PHP is not Java and in PHP you have to make clear, if you want to call a function

assign()

or a method

$object->assign()

In your case the call to the function resides inside another method. $this always refers to the object, in which a method exists, itself.

$this->assign()

How to safely upgrade an Amazon EC2 instance from t1.micro to large?

Use the AWS EC2 console, not ElasticFox.

First Way:

  • Create a new AMI of the instance
  • Launch it

Alternative Way:

  • Make a snapshot of the disk
  • Launch a large EBS instance with the same AMI type (please note that at this point the disk will contain the data that was present when this AMI was created, not your latest changes)
  • Once is fully booted, stop the new instance
  • Detach the root volume from the stopped instance
  • Create a virtual disk from the snapshot created before in the same availability zone of the new instance
  • Attach the root volume to /dev/sda1
  • Start the new instance again

Convert HTML5 into standalone Android App

You could use PhoneGap.

http://phonegap.com/

http://docs.phonegap.com/en/2.1.0/guide_getting-started_android_index.md.html#Getting%20Started%20with%20Android

This has the benefit of being a cross-platform solution. Be warned though that you may need to pay subscription fees. The simplest solution is to just embed a WebView as detailed in @Enigma's answer.

Why is $$ returning the same id as the parent process?

  1. Parentheses invoke a subshell in Bash. Since it's only a subshell it might have the same PID - depends on implementation.
  2. The C program you invoke is a separate process, which has its own unique PID - doesn't matter if it's in a subshell or not.
  3. $$ is an alias in Bash to the current script PID. See differences between $$ and $BASHPID here, and right above that the additional variable $BASH_SUBSHELL which contains the nesting level.

How does Python return multiple values from a function?

Here It is actually returning tuple.

If you execute this code in Python 3:

def get():
    a = 3
    b = 5
    return a,b
number = get()
print(type(number))
print(number)

Output :

<class 'tuple'>
(3, 5)

But if you change the code line return [a,b] instead of return a,b and execute :

def get():
    a = 3
    b = 5
    return [a,b]
number = get()
print(type(number))
print(number)

Output :

<class 'list'>
[3, 5]

It is only returning single object which contains multiple values.

There is another alternative to return statement for returning multiple values, use yield( to check in details see this What does the "yield" keyword do in Python?)

Sample Example :

def get():
    for i in range(5):
        yield i
number = get()
print(type(number))
print(number)
for i in number:
    print(i)

Output :

<class 'generator'>
<generator object get at 0x7fbe5a1698b8>
0
1
2
3
4

How to Select Columns in Editors (Atom,Notepad++, Kate, VIM, Sublime, Textpad,etc) and IDEs (NetBeans, IntelliJ IDEA, Eclipse, Visual Studio, etc)

In TextMate with the mouse: start a selection and keep alt pressed while you move the cursor.

Without the mouse: first select normally using ? and arrows then hit alt and move the cursor.

Searching if value exists in a list of objects using Linq

Try this, I hope it helps you.

 if (lstCustumers.Any(cus => cus.Firstname == "John"))
 {
     //TODO CODE
 }

"undefined" function declared in another file?

You can try one of the following:

Method 1:

  • Assume that your project name is MyProject
  • Go to your path, run go build
  • It will create an executable file as your project name ("MyProject")
  • Then run the executable using ./MyProject

You can do both steps at once by typing go build && ./MyProject. Go files of the package main are compiled to an executable.

Method 2:

  • Just run go run *.go. It won't create any executable but it runs.

How does System.out.print() work?

Evidently, the compiler was made in a confusing way although the compiler developers thought they added some smartness. The true smartness they should really add is to look entire argument and interpret + operator consistently. For example, System.out.println(1+2+"hello"+3+4); should output 3hello7 instead of 3hello34

How can I convert a date into an integer?

Using the builtin Date.parse function which accepts input in ISO8601 format and directly returns the desired integer return value:

var dates_as_int = dates.map(Date.parse);

C# "as" cast vs classic cast

The as operator is useful in a couple of circumstances.

  1. When you only need to know an object is of a specific type but don't need to specifically act on members of that type
  2. When you'd like to avoid exceptions and instead explicitly deal with null
  3. You want to know if there is a CLR conversion between the objects and not just some user defined conversion.

The 3rd point is subtle but important. There is not a 1-1 mapping between which casts will succeed with the cast operator and those which will succeed with the as operator. The as operator is strictly limited to CLR conversions and will not consider user defined conversions (the cast operator will).

Specifically the as operator only allows for the following (from section 7.9.11 of the C# lang spec)

  • An identity (§6.1.1), implicit reference (§6.1.6), boxing (§6.1.7), explicit reference (§6.2.4), or unboxing (§6.2.5) conversion exists from the type of E to T.
  • The type of E or T is an open type.
  • E is the null literal.

How to automate drag & drop functionality using Selenium WebDriver Java

Selenium has pretty good documentation. Here is a link to the specific part of the API you are looking for:

WebElement element = driver.findElement(By.name("source"));

WebElement target = driver.findElement(By.name("target"));

(new Actions(driver)).dragAndDrop(element, target).perform();

This is to drag and drop a single file, How to drag and drop multiple files.

Remove x-axis label/text in chart.js

If you want the labels to be retained for the tooltip, but not displayed below the bars the following hack might be useful. I made this change for use on an private intranet application and have not tested it for efficiency or side-effects, but it did what I needed.

At about line 71 in chart.js add a property to hide the bar labels:

// Boolean - Whether to show x-axis labels
barShowLabels: true,

At about line 1500 use that property to suppress changing this.endPoint (it seems that other portions of the calculation code are needed as chunks of the chart disappeared or were rendered incorrectly if I disabled anything more than this line).

if (this.xLabelRotation > 0) {
    if (this.ctx.barShowLabels) {
        this.endPoint -= Math.sin(toRadians(this.xLabelRotation)) * originalLabelWidth + 3;
    } else {
        // don't change this.endPoint
    }
}

At about line 1644 use the property to suppress the label rendering:

if (ctx.barShowLabels) {    
    ctx.fillText(label, 0, 0);
}

I'd like to make this change to the Chart.js source but aren't that familiar with git and don't have the time to test rigorously so would rather avoid breaking anything.

Google OAuth 2 authorization - Error: redirect_uri_mismatch

In any flow where you retrieved an authorization code on the client side, such as the GoogleAuth.grantOfflineAccess() API, and now you want to pass the code to your server, redeem it, and store the access and refresh tokens, then you have to use the literal string postmessage instead of the redirect_uri.

For example, building on the snippet in the Ruby doc:

client_secrets = Google::APIClient::ClientSecrets.load('client_secrets.json')
auth_client = client_secrets.to_authorization
auth_client.update!(
  :scope => 'profile https://www.googleapis.com/auth/drive.metadata.readonly',
  :redirect_uri => 'postmessage' # <---- HERE
)

# Inject user's auth_code here:
auth_client.code = "4/lRCuOXzLMIzqrG4XU9RmWw8k1n3jvUgsI790Hk1s3FI"
tokens = auth_client.fetch_access_token!
# { "access_token"=>..., "expires_in"=>3587, "id_token"=>..., "refresh_token"=>..., "token_type"=>"Bearer"}

The only Google documentation to even mention postmessage is this old Google+ sign-in doc. Here's a screenshot and archive link since G+ is closing and this link will likely go away:

Legacy Google+ API DOC

It is absolutely unforgivable that the doc page for Offline Access doesn't mention this. #FacePalm

Check if element is clickable in Selenium Java

There are certain things you have to take care:

  • WebDriverWait inconjunction with ExpectedConditions as elementToBeClickable() returns the WebElement once it is located and clickable i.e. visible and enabled.
  • In this process, WebDriverWait will ignore instances of NotFoundException that are encountered by default in the until condition.
  • Once the duration of the wait expires on the desired element not being located and clickable, will throw a timeout exception.
  • The different approach to address this issue are:
    • To invoke click() as soon as the element is returned, you can use:

      new WebDriverWait(driver, 10).until(ExpectedConditions.elementToBeClickable(By.xpath("(//div[@id='brandSlider']/div[1]/div/div/div/img)[50]"))).click();
      
    • To simply validate if the element is located and clickable, wrap up the WebDriverWait in a try-catch{} block as follows:

      try {
             new WebDriverWait(driver, 10).until(ExpectedConditions.elementToBeClickable(By.xpath("(//div[@id='brandSlider']/div[1]/div/div/div/img)[50]")));
             System.out.println("Element is clickable");
           }
      catch(TimeoutException e) {
             System.out.println("Element isn't clickable");
          }
      
    • If WebDriverWait returns the located and clickable element but the element is still not clickable, you need to invoke executeScript() method as follows:

      WebElement element = new WebDriverWait(driver, 10).until(ExpectedConditions.elementToBeClickable(By.xpath("(//div[@id='brandSlider']/div[1]/div/div/div/img)[50]"))); 
      ((JavascriptExecutor)driver).executeScript("arguments[0].click();", element);
      

How do I dispatch_sync, dispatch_async, dispatch_after, etc in Swift 3, Swift 4, and beyond?

in Xcode 8 use:

DispatchQueue.global(qos: .userInitiated).async { }

On localhost, how do I pick a free port number?

You can listen on whatever port you want; generally, user applications should listen to ports 1024 and above (through 65535). The main thing if you have a variable number of listeners is to allocate a range to your app - say 20000-21000, and CATCH EXCEPTIONS. That is how you will know if a port is unusable (used by another process, in other words) on your computer.

However, in your case, you shouldn't have a problem using a single hard-coded port for your listener, as long as you print an error message if the bind fails.

Note also that most of your sockets (for the slaves) do not need to be explicitly bound to specific port numbers - only sockets that wait for incoming connections (like your master here) will need to be made a listener and bound to a port. If a port is not specified for a socket before it is used, the OS will assign a useable port to the socket. When the master wants to respond to a slave that sends it data, the address of the sender is accessible when the listener receives data.

I presume you will be using UDP for this?

How do I replace whitespaces with underscore?

OP is using python, but in javascript (something to be careful of since the syntaxes are similar.

// only replaces the first instance of ' ' with '_'
"one two three".replace(' ', '_'); 
=> "one_two three"

// replaces all instances of ' ' with '_'
"one two three".replace(/\s/g, '_');
=> "one_two_three"

Only read selected columns

You could also use JDBC to achieve this. Let's create a sample csv file.

write.table(x=mtcars, file="mtcars.csv", sep=",", row.names=F, col.names=T) # create example csv file

Download and save the the CSV JDBC driver from this link: http://sourceforge.net/projects/csvjdbc/files/latest/download

> library(RJDBC)

> path.to.jdbc.driver <- "jdbc//csvjdbc-1.0-18.jar"
> drv <- JDBC("org.relique.jdbc.csv.CsvDriver", path.to.jdbc.driver)
> conn <- dbConnect(drv, sprintf("jdbc:relique:csv:%s", getwd()))

> head(dbGetQuery(conn, "select * from mtcars"), 3)
   mpg cyl disp  hp drat    wt  qsec vs am gear carb
1   21   6  160 110  3.9  2.62 16.46  0  1    4    4
2   21   6  160 110  3.9 2.875 17.02  0  1    4    4
3 22.8   4  108  93 3.85  2.32 18.61  1  1    4    1

> head(dbGetQuery(conn, "select mpg, gear from mtcars"), 3)
   MPG GEAR
1   21    4
2   21    4
3 22.8    4

CSS background image to fit width, height should auto-scale in proportion

Background image is not Set Perfect then his css is problem create so his css file change to below code

_x000D_
_x000D_
html {  _x000D_
  background-image: url("example.png");  _x000D_
  background-repeat: no-repeat;  _x000D_
  background-position: 0% 0%;_x000D_
  background-size: 100% 100%;_x000D_
}
_x000D_
_x000D_
_x000D_

%; background-size: 100% 100%;"

Proper usage of .net MVC Html.CheckBoxFor

By default, the below code will NOT generate a checked Check Box as model properties override the html attributes:

@Html.CheckBoxFor(m => m.SomeBooleanProperty, new { @checked = "checked" });

Instead, in your GET Action method, the following needs to be done:

model.SomeBooleanProperty = true;

The above will preserve your selection(If you uncheck the box) even if model is not valid(i.e. some error occurs on posting the form).

However, the following code will certainly generate a checked checkbox, but will not preserve your uncheck responses, instead make the checkbox checked every time on errors in form.

 @Html.CheckBox("SomeBooleanProperty", new { @checked = "checked" });

UPDATE

//Get Method
   public ActionResult CreateUser(int id)
   {
        model.SomeBooleanProperty = true;         
   }

Above code would generate a checked check Box at starting and will also preserve your selection even on errors in form.

how to use math.pi in java

Here is usage of Math.PI to find circumference of circle and Area First we take Radius as a string in Message Box and convert it into integer

public class circle {

    public static void main(String[] args) {
        // TODO code application logic here

        String rad;

        float radius,area,circum;

       rad = JOptionPane.showInputDialog("Enter the Radius of circle:");

        radius = Integer.parseInt(rad);
        area = (float) (Math.PI*radius*radius);
        circum = (float) (2*Math.PI*radius);

        JOptionPane.showMessageDialog(null, "Area: " + area,"AREA",JOptionPane.INFORMATION_MESSAGE);
        JOptionPane.showMessageDialog(null, "circumference: " + circum, "Circumfernce",JOptionPane.INFORMATION_MESSAGE);
    }

}

AngularJS sorting by property

The following allows for the ordering of objects by key OR by a key within an object.

In template you can do something like:

    <li ng-repeat="(k,i) in objectList | orderObjectsBy: 'someKey'">

Or even:

    <li ng-repeat="(k,i) in objectList | orderObjectsBy: 'someObj.someKey'">

The filter:

app.filter('orderObjectsBy', function(){
 return function(input, attribute) {
    if (!angular.isObject(input)) return input;

    // Filter out angular objects.
    var array = [];
    for(var objectKey in input) {
      if (typeof(input[objectKey])  === "object" && objectKey.charAt(0) !== "$")
        array.push(input[objectKey]);
    }

    var attributeChain = attribute.split(".");

    array.sort(function(a, b){

      for (var i=0; i < attributeChain.length; i++) {
        a = (typeof(a) === "object") && a.hasOwnProperty( attributeChain[i]) ? a[attributeChain[i]] : 0;
        b = (typeof(b) === "object") && b.hasOwnProperty( attributeChain[i]) ? b[attributeChain[i]] : 0;
      }

      return parseInt(a) - parseInt(b);
    });

    return array;
 }
})

Which Android IDE is better - Android Studio or Eclipse?

My first choice is Android Studio. its has great feature to develop android application.

Eclipse is not that hard to learn also.If you're going to be learning Android development from the start, I can recommend Hello, Android, which I just finished. It shows you exactly how to use all the features of Eclipse that are useful for developing Android apps. There's also a brief section on getting set up to develop from the command line and from other IDEs.

Sort JavaScript object by key

It's 2019 and we have a 2019 way to solve this :)

Object.fromEntries(Object.entries({b: 3, a:8, c:1}).sort())

How to create an array of 20 random bytes?

Create a Random object with a seed and get the array random by doing:

public static final int ARRAY_LENGTH = 20;

byte[] byteArray = new byte[ARRAY_LENGTH];
new Random(System.currentTimeMillis()).nextBytes(byteArray);
// get fisrt element
System.out.println("Random byte: " + byteArray[0]);

Order discrete x scale by frequency/value

Hadley has been developing a package called forcats. This package makes the task so much easier. You can exploit fct_infreq() when you want to change the order of x-axis by the frequency of a factor. In the case of the mtcars example in this post, you want to reorder levels of cyl by the frequency of each level. The level which appears most frequently stays on the left side. All you need is the fct_infreq().

library(ggplot2)
library(forcats)

ggplot(mtcars, aes(fct_infreq(factor(cyl)))) +
geom_bar() +
labs(x = "cyl")

If you wanna go the other way around, you can use fct_rev() along with fct_infreq().

ggplot(mtcars, aes(fct_rev(fct_infreq(factor(cyl))))) +
geom_bar() +
labs(x = "cyl") 

enter image description here

400 vs 422 response to POST of data

You should actually return "200 OK" and in the response body include a message about what happened with the posted data. Then it's up to your application to understand the message.

The thing is, HTTP status codes are exactly that - HTTP status codes. And those are meant to have meaning only at the transportation layer, not at the application layer. The application layer should really never even know that HTTP is being used. If you switched your transportation layer from HTTP to Homing Pigeons, it should not affect your application layer in any way.

Let me give you a non-virtual example. Let's say you fall in love with a girl and she loves you back but her family moves to a completely different country. She gives you her new snail-mail address. Naturally, you decide to send her a love letter. So you write your letter, put it into an envelope, write her address on the envelope, put a stamp on it and send it. Now let's consider these scenarios

  1. You forgot to write a street name. You will receive an unopened letter back with a message written on it saying that the address is malformed. You screwed up the request and the receiving post office is unable to handle it. That's the equivalent of receiving "400 Bad Request".
  2. So you fix the address and send the letter again. But due to some bad luck you totaly misspelled the name of the street. You will get the letter back again with a message saying, that the address doesn't exist. That's the equivalent of receiving "404 Not Found".
  3. You fix the address again and this time you manage to write the address correctly. Your girl receives the letter and writes you back. It's the equivalent of receiving "200 OK". However, this does not mean that you will like what she wrote in her letter. It simply means that she received your message and has a response for you. Until you open the envelope and read her letter you cannot know whether she misses you dearly or wants to break up with you.

In short: Returning "200 OK" doesn't mean that the server app has good news for you. It only means that it has some news.

PS: The 422 status code has a meaning only in the context of WebDAV. If you're not working with WebDAV, then 422 has exactly the same standard meaning as any other non-standard code = which is none.

When should an IllegalArgumentException be thrown?

The API doc for IllegalArgumentException:

Thrown to indicate that a method has been passed an illegal or inappropriate argument.

From looking at how it is used in the JDK libraries, I would say:

  • It seems like a defensive measure to complain about obviously bad input before the input can get into the works and cause something to fail halfway through with a nonsensical error message.

  • It's used for cases where it would be too annoying to throw a checked exception (although it makes an appearance in the java.lang.reflect code, where concern about ridiculous levels of checked-exception-throwing is not otherwise apparent).

I would use IllegalArgumentException to do last ditch defensive argument checking for common utilities (trying to stay consistent with the JDK usage). Or where the expectation is that a bad argument is a programmer error, similar to an NullPointerException. I wouldn't use it to implement validation in business code. I certainly wouldn't use it for the email example.

MySQL server has gone away - in exactly 60 seconds

I solved this problem with

if( !mysql_ping($link) ) $link = mysql_connect("$MYSQL_Host","$MYSQL_User","$MYSQL_Pass", true);

Extension methods must be defined in a non-generic static class

Try changing it to static class and back. That might resolve visual studio complaining when it's a false positive.

An unhandled exception of type 'System.TypeInitializationException' occurred in EntityFramework.dll

Read the message:

Only one <configSections> element allowed per config file and if present must be the first child of the root <configuration> element.

Move the configSections element to the top - just above where system.data is currently.

How do I use a custom Serializer with Jackson?

Jackson's JSON Views might be a simpler way of achieving your requirements, especially if you have some flexibility in your JSON format.

If {"id":7, "itemNr":"TEST", "createdBy":{id:3}} is an acceptable representation then this will be very easy to achieve with very little code.

You would just annotate the name field of User as being part of a view, and specify a different view in your serialisation request (the un-annotated fields would be included by default)

For example: Define the views:

public class Views {
    public static class BasicView{}
    public static class CompleteUserView{}
}

Annotate the User:

public class User {
    public final int id;

    @JsonView(Views.CompleteUserView.class)
    public final String name;

    public User(int id, String name) {
        this.id = id;
        this.name = name;
    }
}

And serialise requesting a view which doesn't contain the field you want to hide (non-annotated fields are serialised by default):

objectMapper.getSerializationConfig().withView(Views.BasicView.class);

How to play ringtone/alarm sound in Android

Your example is basically what I'm using. It never works on the emulator, however, because the emulator doesn't have any ringtones by default, and content://settings/system/ringtone doesn't resolve to anything playable. It works fine on my actual phone.

SyntaxError: multiple statements found while compiling a single statement

In the shell, you can't execute more than one statement at a time:

>>> x = 5
y = 6
SyntaxError: multiple statements found while compiling a single statement

You need to execute them one by one:

>>> x = 5
>>> y = 6
>>>

When you see multiple statements are being declared, that means you're seeing a script, which will be executed later. But in the interactive interpreter, you can't do more than one statement at a time.

What is the difference between function and procedure in PL/SQL?

A procedure does not have a return value, whereas a function has.

Example:

CREATE OR REPLACE PROCEDURE my_proc
   (p_name IN VARCHAR2 := 'John') as begin ... end

CREATE OR REPLACE FUNCTION my_func
   (p_name IN VARCHAR2 := 'John') return varchar2 as begin ... end

Notice how the function has a return clause between the parameter list and the "as" keyword. This means that it is expected to have the last statement inside the body of the function read something like:

return(my_varchar2_local_variable);

Where my_varchar2_local_variable is some varchar2 that should be returned by that function.

JQuery - Set Attribute value

Use an ID to uniquely identify the checkbox. Your current example is trying to select the checkbox with an id of '#chk0':

<input type="checkbox" id="chk0" name="chk0" value="true" disabled>

$('#chk0').attr("disabled", "disabled");

You'll also need to remove the attribute for disabled to enable the checkbox. Something like:

$('#chk0').removeAttr("disabled");

See the docs for removeAttr

The value XHTML for disabling/enabling an input element is as follows:

<input type="checkbox" id="chk0" name="chk0" value="true" disabled="disabled" />
<input type="checkbox" id="chk0" name="chk0" value="true" />

Note that it's the absence of the disabled attribute that makes the input element enabled.

Get multiple elements by Id

You should use querySelectorAll, this writes every occurrence in an array and it allows you to use forEach to get individual element.

document.querySelectorAll('[id=test]').forEach(element=> 
    document.write(element);
});

Java compile error: "reached end of file while parsing }"

It happens when you don't properly close the code block:

if (condition){
  // your code goes here*
  { // This doesn't close the code block

Correct way:

if (condition){
  // your code goes here
} // Close the code block

Java 8 lambda get and remove element from list

I'm sure this will be an unpopular answer, but it works...

ProducerDTO[] p = new ProducerDTO[1];
producersProcedureActive
            .stream()
            .filter(producer -> producer.getPod().equals(pod))
            .findFirst()
            .ifPresent(producer -> {producersProcedureActive.remove(producer); p[0] = producer;}

p[0] will either hold the found element or be null.

The "trick" here is circumventing the "effectively final" problem by using an array reference that is effectively final, but setting its first element.

Android check null or empty string in Android

Use TextUtils.isEmpty( someString )

String myString = null;

if (TextUtils.isEmpty(myString)) {
    return; // or break, continue, throw
}

// myString is neither null nor empty if this point is reached
Log.i("TAG", myString);

Notes

  • The documentation states that both null and zero length are checked for. No need to reinvent the wheel here.
  • A good practice to follow is early return.

Get current user id in ASP.NET Identity 2.0

In order to get CurrentUserId in Asp.net Identity 2.0, at first import Microsoft.AspNet.Identity:

C#:

using Microsoft.AspNet.Identity;

VB.NET:

Imports Microsoft.AspNet.Identity


And then call User.Identity.GetUserId() everywhere you want:

strCurrentUserId = User.Identity.GetUserId()

This method returns current user id as defined datatype for userid in database (the default is String).

"The certificate chain was issued by an authority that is not trusted" when connecting DB in VM Role from Azure website

I ran into this error trying to run the profiler, even though my connection had Trust server certificate checked and I added TrustServerCertificate=True in the Advanced Section. I changed to an instance of SSMS running as administrator and the profiler started with no problem. (I previously had found that when my connections even to local took a long time to connect, running as administrator helped).

Are PHP Variables passed by value or by reference?

PHP variables are assigned by value, passed to functions by value and when containing/representing objects are passed by reference. You can force variables to pass by reference using an '&'.

Assigned by value/reference example:

$var1 = "test";
$var2 = $var1;
$var2 = "new test";
$var3 = &$var2;
$var3 = "final test";

print ("var1: $var1, var2: $var2, var3: $var3);

output:

var1: test, var2: final test, var3: final test

Passed by value/reference example:

$var1 = "foo";
$var2 = "bar";

changeThem($var1, $var2);

print "var1: $var1, var2: $var2";

function changeThem($var1, &$var2){
    $var1 = "FOO";
    $var2 = "BAR";
}

output:

var1: foo, var2 BAR

Object variables passed by reference example:

class Foo{
    public $var1;

    function __construct(){
        $this->var1 = "foo";
    }

    public function printFoo(){
        print $this->var1;
    }
}


$foo = new Foo();

changeFoo($foo);

$foo->printFoo();

function changeFoo($foo){
    $foo->var1 = "FOO";
}

output:

FOO

(The last example could be better probably.)

How do I uniquely identify computers visiting my web site?

A possibility is using flash cookies:

  • Ubiquitous availability (95 percent of visitors will probably have flash)
  • You can store more data per cookie (up to 100 KB)
  • Shared across browsers, so more likely to uniquely identify a machine
  • Clearing the browser cookies does not remove the flash cookies.

You'll need to build a small (hidden) flash movie to read and write them.

Whatever route you pick, make sure your users opt IN to being tracked, otherwise you're invading their privacy and become one of the bad guys.

jQuery or JavaScript auto click

You haven't provided your javascript code, but the usual cause of this type of issue is not waiting till the page is loaded. Remember that most javascript is executed before the DOM is loaded, so code trying to manipulate it won't work.

To run code after the page has finished loading, use the $(document).ready callback:

$(document).ready(function(){
  $('#some-id').trigger('click');
});

What is mutex and semaphore in Java ? What is the main difference?

Mutex is binary semaphore. It must be initialized with 1, so that the First Come First Serve principle is met. This brings us to the other special property of each mutex: the one who did down, must be the one who does up. Ergo we have obtained mutual exclusion over some resource.

Now you could see that a mutex is a special case of general semaphore.

Passing A List Of Objects Into An MVC Controller Method Using jQuery Ajax

I am using a .Net Core 2.1 Web Application and could not get a single answer here to work. I either got a blank parameter (if the method was called at all) or a 500 server error. I started playing with every possible combination of answers and finally got a working result.

In my case the solution was as follows:

Script - stringify the original array (without using a named property)

    $.ajax({
        type: 'POST',
        contentType: 'application/json; charset=utf-8',
        url: mycontrolleraction,
        data: JSON.stringify(things)
    });

And in the controller method, use [FromBody]

    [HttpPost]
    public IActionResult NewBranch([FromBody]IEnumerable<Thing> things)
    {
        return Ok();
    }

Failures include:

  • Naming the content

    data: { content: nodes }, // Server error 500

  • Not having the contentType = Server error 500

Notes

  • dataType is not needed, despite what some answers say, as that is used for the response decoding (so not relevant to the request examples here).
  • List<Thing> also works in the controller method

Carry Flag, Auxiliary Flag and Overflow Flag in Assembly

Carry Flag

The rules for turning on the carry flag in binary/integer math are two:

  1. The carry flag is set if the addition of two numbers causes a carry out of the most significant (leftmost) bits added. 1111 + 0001 = 0000 (carry flag is turned on)

  2. The carry (borrow) flag is also set if the subtraction of two numbers requires a borrow into the most significant (leftmost) bits subtracted. 0000 - 0001 = 1111 (carry flag is turned on) Otherwise, the carry flag is turned off (zero).

    • 0111 + 0001 = 1000 (carry flag is turned off [zero])
    • 1000 - 0001 = 0111 (carry flag is turned off [zero])

In unsigned arithmetic, watch the carry flag to detect errors.

In signed arithmetic, the carry flag tells you nothing interesting.

Overflow Flag

The rules for turning on the overflow flag in binary/integer math are two:

  1. If the sum of two numbers with the sign bits off yields a result number with the sign bit on, the "overflow" flag is turned on. 0100 + 0100 = 1000 (overflow flag is turned on)

  2. If the sum of two numbers with the sign bits on yields a result number with the sign bit off, the "overflow" flag is turned on. 1000 + 1000 = 0000 (overflow flag is turned on)

Otherwise the "overflow" flag is turned off

  • 0100 + 0001 = 0101 (overflow flag is turned off)
  • 0110 + 1001 = 1111 (overflow flag turned off)
  • 1000 + 0001 = 1001 (overflow flag turned off)
  • 1100 + 1100 = 1000 (overflow flag is turned off)

Note that you only need to look at the sign bits (leftmost) of the three numbers to decide if the overflow flag is turned on or off.

If you are doing two's complement (signed) arithmetic, overflow flag on means the answer is wrong - you added two positive numbers and got a negative, or you added two negative numbers and got a positive.

If you are doing unsigned arithmetic, the overflow flag means nothing and should be ignored.

For more clarification please refer: http://teaching.idallen.com/dat2343/10f/notes/040_overflow.txt

How to format background color using twitter bootstrap?

Move your row before <div class="container marketing"> and wrap it with a new container, because current container width is 1170px (not 100%):

<div class='hero'>
  <div class="row">
   ...
  </div>
</div>

CSS:

.hero {
  background-color: #2ba6cb;
  padding: 0 90px;
}

How to get the current branch name in Git?

In Netbeans, ensure that versioning annotations are enabled (View -> Show Versioning Labels). You can then see the branch name next to project name.

http://netbeans.org/bugzilla/show_bug.cgi?id=213582

How to display string that contains HTML in twig template?

if you don't need variable, you can define text in
translations/messages.en.yaml :
CiteExampleHtmlCode: "<b> my static text </b>"

then use it with twig:
templates/about/index.html.twig
… {{ 'CiteExampleHtmlCode' }}
or if you need multilangages like me:
… {{ 'CiteExampleHtmlCode' | trans }}

Let's have a look of https://symfony.com/doc/current/translation.html for more information about translations use.

What is w3wp.exe?

w3wp.exe is a process associated with the application pool in IIS. If you have more than one application pool, you will have more than one instance of w3wp.exe running. This process usually allocates large amounts of resources. It is important for the stable and secure running of your computer and should not be terminated.

You can get more information on w3wp.exe here

http://www.processlibrary.com/en/directory/files/w3wp/25761/

Convert string to ASCII value python

You can use a list comprehension:

>>> s = 'hi'
>>> [ord(c) for c in s]
[104, 105]

"Mixed content blocked" when running an HTTP AJAX operation in an HTTPS page

If your API code is running on a node.js server then you need to focus your attention there, not in Apache or NGINX. Mikel is right, changing the API URL to HTTPS is the answer but if your API is calling a node.js server, it better be set up for HTTPS! And of course, the node.js server can be on any unused port, it doesn't have to be port 443.

Get sum of MySQL column in PHP

Let us use the following image as an example for the data in our MySQL Database:

enter image description here

Now, as the question mentions, we need to find the sum of a particular column in a table. For example, let us add all the values of column "duration_sec" for the date '09-10-2018' and only status 'off'

For this condition, the following would be the sql query and code:

$sql_qry = "SELECT SUM(duration_sec) AS count 
    FROM tbl_npt 
    WHERE date='09-10-2018' AND status='off'";

$duration = $connection->query($sql_qry);
$record = $duration->fetch_array();
$total = $record['count'];

echo $total;

How would you make two <div>s overlap?

With absolute or relative positioning, you can do all sorts of overlapping. You've probably want the logo to be styled as such:

div#logo {
  position: absolute;
  left: 100px; // or whatever
}

Note: absolute position has its eccentricities. You'll probably have to experiment a little, but it shouldn't be too hard to do what you want.

How to print a groupby object

Simply do:

grouped_df = df.groupby('A')

for key, item in grouped_df:
    print(grouped_df.get_group(key), "\n\n")

This also works,

grouped_df = df.groupby('A')    
gb = grouped_df.groups

for key, values in gb.iteritems():
    print(df.ix[values], "\n\n")

For selective key grouping: Insert the keys you want inside the key_list_from_gb, in following, using gb.keys(): For Example,

gb = grouped_df.groups
gb.keys()

key_list_from_gb = [key1, key2, key3]

for key, values in gb.items():
    if key in key_list_from_gb:
        print(df.ix[values], "\n")

Creating a blurring overlay view

If adds a dark blur view for tableView, this will beautifully make it:

tableView.backgroundColor = .clear
let blurEffect = UIBlurEffect(style: .dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = tableView.bounds
blurEffectView.autoresizingMask = [.flexibleHeight, .flexibleWidth]


// Assigning blurEffectView to backgroundView instead of addSubview to tableView makes tableView cell not blocked by blurEffectView 
tableView.backgroundView = blurEffectView

Cannot create JDBC driver of class ' ' for connect URL 'null' : I do not understand this exception

Did you try to specify resource only in context.xml

<Resource name="jdbc/PollDatasource" auth="Container" type="javax.sql.DataSource"
driverClassName="org.apache.derby.jdbc.EmbeddedDriver"
url="jdbc:derby://localhost:1527/poll_database;create=true"
username="suhail" password="suhail"
maxActive="20" maxIdle="10" maxWait="-1" />

and remove <resource-ref> section from web.xml?

In one project I've seen configuration without <resource-ref> section in web.xml and it worked.

It's an educated guess, but I think <resource-ref> declaration of JNDI resource named jdbc/PollDatasource in web.xml may override declaration of resource with same name in context.xml and the declaration in web.xml is missing both driverClassName and url hence the NPEs for that properties.

Exporting result of select statement to CSV format in DB2

You can run this command from the DB2 command line processor (CLP) or from inside a SQL application by calling the ADMIN_CMD stored procedure

EXPORT TO result.csv OF DEL MODIFIED BY NOCHARDEL 
SELECT col1, col2, coln FROM testtable;

There are lots of options for IMPORT and EXPORT that you can use to create a data file that meets your needs. The NOCHARDEL qualifier will suppress double quote characters that would otherwise appear around each character column.

Keep in mind that any SELECT statement can be used as the source for your export, including joins or even recursive SQL. The export utility will also honor the sort order if you specify an ORDER BY in your SELECT statement.

What is the difference between parseInt() and Number()?

Its a good idea to stay away from parseInt and use Number and Math.round unless you need hex or octal. Both can use strings. Why stay away from it?

parseInt(0.001, 10)
0

parseInt(-0.0000000001, 10)
-1

parseInt(0.0000000001, 10)
1

parseInt(4000000000000000000000, 10)
4

It completly butchers really large or really small numbers. Oddly enough it works normally if these inputs are a string.

parseInt("-0.0000000001", 10)
0

parseInt("0.0000000001", 10)
0

parseInt("4000000000000000000000", 10)
4e+21

Instead of risking hard to find bugs with this and the other gotchas people mentioned, I would just avoid parseInt unless you need to parse something other than base 10. Number, Math.round, Math.foor, and .toFixed(0) can all do the same things parseInt can be used for without having these types of bugs.

If you really want or need to use parseInt for some of it's other qualities, never use it to convert floats to ints.

Using C# to read/write Excel files (.xls/.xlsx)

I'm a big fan of using EPPlus to perform these types of actions. EPPlus is a library you can reference in your project and easily create/modify spreadsheets on a server. I use it for any project that requires an export function.

Here's a nice blog entry that shows how to use the library, though the library itself should come with some samples that explain how to use it.

Third party libraries are a lot easier to use than Microsoft COM objects, in my opinion. I would suggest giving it a try.

How to create and use resources in .NET

The above didn't actually work for me as I had expected with Visual Studio 2010. It wouldn't let me access Properties.Resources, said it was inaccessible due to permission issues. I ultimately had to change the Persistence settings in the properties of the resource and then I found how to access it via the Resources.Designer.cs file, where it had an automatic getter that let me access the icon, via MyNamespace.Properties.Resources.NameFromAddingTheResource. That returns an object of type Icon, ready to just use.

Should I use typescript? or I can just use ES6?

Decision tree between ES5, ES6 and TypeScript

Do you mind having a build step?

  • Yes - Use ES5
  • No - keep going

Do you want to use types?

  • Yes - Use TypeScript
  • No - Use ES6

More Details

ES5 is the JavaScript you know and use in the browser today it is what it is and does not require a build step to transform it into something that will run in today's browsers

ES6 (also called ES2015) is the next iteration of JavaScript, but it does not run in today's browsers. There are quite a few transpilers that will export ES5 for running in browsers. It is still a dynamic (read: untyped) language.

TypeScript provides an optional typing system while pulling in features from future versions of JavaScript (ES6 and ES7).

Note: a lot of the transpilers out there (i.e. babel, TypeScript) will allow you to use features from future versions of JavaScript today and exporting code that will still run in today's browsers.

MySQL fails on: mysql "ERROR 1524 (HY000): Plugin 'auth_socket' is not loaded"

You can try these some steps:

Stop Mysql Service 1st sudo /etc/init.d/mysql stop

Login as root without password sudo mysqld_safe --skip-grant-tables &

After login mysql terminal you should need execute commands more:

use mysql;

UPDATE mysql.user SET authentication_string=PASSWORD('solutionclub3@*^G'), plugin='mysql_native_password' WHERE User='root';

flush privileges;

sudo mysqladmin -u root -p -S /var/run/mysqld/mysqld.sock shutdown

After you restart your mysql server If you still facing error you must visit : Reset MySQL 5.7 root password Ubuntu 16.04

Can we instantiate an abstract class directly?

You can't directly instantiate an abstract class, but you can create an anonymous class when there is no concrete class:

public class AbstractTest {
    public static void main(final String... args) {
        final Printer p = new Printer() {
            void printSomethingOther() {
                System.out.println("other");
            }
            @Override
            public void print() {
                super.print();
                System.out.println("world");
                printSomethingOther(); // works fine
            }
        };
        p.print();
        //p.printSomethingOther(); // does not work
    }
}

abstract class Printer {
    public void print() {
        System.out.println("hello");
    }
}

This works with interfaces, too.

Is there an easy way to add a border to the top and bottom of an Android View?

Write down below code

<View
    android:layout_width="wrap_content"
    android:layout_height="2dip"
    android:layout_below="@+id/topics_text"
    android:layout_marginTop="7dp"
    android:layout_margin="10dp"
    android:background="#ffffff" />

Getting results between two dates in PostgreSQL

 SELECT *
   FROM mytable
  WHERE (start_date, end_date) OVERLAPS ('2012-01-01'::DATE, '2012-04-12'::DATE);

Datetime functions is the relevant section in the docs.

How to execute a .bat file from a C# windows form app?

Here is what you are looking for:

Service hangs up at WaitForExit after calling batch file

It's about a question as to why a service can't execute a file, but it shows all the code necessary to do so.

Does Google Chrome work with Selenium IDE (as Firefox does)?

Just fyi . This is available as nuget package in visual studio environment. Please let me know if you need more information as I have used it. URL can be found Link to nuget

You can also find some information here. Blog with more details

How do I change the background color with JavaScript?

I would prefer to see the use of a css class here. It avoids having hard to read colors / hex codes in javascript.

document.body.className = className;

iOS detect if user is on an iPad

This is part of UIDevice as of iOS 3.2, e.g.:

[UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad

Detect Scroll Up & Scroll down in ListView

this is a simple implementation:

lv.setOnScrollListener(new OnScrollListener() {
        private int mLastFirstVisibleItem;

        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {

        }

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

            if(mLastFirstVisibleItem<firstVisibleItem)
            {
                Log.i("SCROLLING DOWN","TRUE");
            }
            if(mLastFirstVisibleItem>firstVisibleItem)
            {
                Log.i("SCROLLING UP","TRUE");
            }
            mLastFirstVisibleItem=firstVisibleItem;

        }
    });

and if you need more precision, you can use this custom ListView class:

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.AbsListView;
import android.widget.ListView;

/**
 * Created by root on 26/05/15.
 */
public class ScrollInterfacedListView extends ListView {


    private OnScrollListener onScrollListener;
    private OnDetectScrollListener onDetectScrollListener;

    public ScrollInterfacedListView(Context context) {
        super(context);
        onCreate(context, null, null);
    }

    public ScrollInterfacedListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        onCreate(context, attrs, null);
    }

    public ScrollInterfacedListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        onCreate(context, attrs, defStyle);
    }

    @SuppressWarnings("UnusedParameters")
    private void onCreate(Context context, AttributeSet attrs, Integer defStyle) {
        setListeners();
    }

    private void setListeners() {
        super.setOnScrollListener(new OnScrollListener() {

            private int oldTop;
            private int oldFirstVisibleItem;

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
                if (onScrollListener != null) {
                    onScrollListener.onScrollStateChanged(view, scrollState);
                }
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                if (onScrollListener != null) {
                    onScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
                }

                if (onDetectScrollListener != null) {
                    onDetectedListScroll(view, firstVisibleItem);
                }
            }

            private void onDetectedListScroll(AbsListView absListView, int firstVisibleItem) {
                View view = absListView.getChildAt(0);
                int top = (view == null) ? 0 : view.getTop();

                if (firstVisibleItem == oldFirstVisibleItem) {
                    if (top > oldTop) {
                        onDetectScrollListener.onUpScrolling();
                    } else if (top < oldTop) {
                        onDetectScrollListener.onDownScrolling();
                    }
                } else {
                    if (firstVisibleItem < oldFirstVisibleItem) {
                        onDetectScrollListener.onUpScrolling();
                    } else {
                        onDetectScrollListener.onDownScrolling();
                    }
                }

                oldTop = top;
                oldFirstVisibleItem = firstVisibleItem;
            }
        });
    }

    @Override
    public void setOnScrollListener(OnScrollListener onScrollListener) {
        this.onScrollListener = onScrollListener;
    }

    public void setOnDetectScrollListener(OnDetectScrollListener onDetectScrollListener) {
        this.onDetectScrollListener = onDetectScrollListener;
    }


    public interface OnDetectScrollListener {

        void onUpScrolling();

        void onDownScrolling();
    }

}

an example for use: (don't forget to add it as an Xml Tag in your layout.xml)

scrollInterfacedListView.setOnDetectScrollListener(new ScrollInterfacedListView.OnDetectScrollListener() {
            @Override
            public void onUpScrolling() {
               //Do your thing
            }

            @Override
            public void onDownScrolling() {

             //Do your thing
            }
        });

select data up to a space?

You can use a combiation of LEFT and CHARINDEX to find the index of the first space, and then grab everything to the left of that.

 SELECT LEFT(YourColumn, charindex(' ', YourColumn) - 1) 

And in case any of your columns don't have a space in them:

SELECT LEFT(YourColumn, CASE WHEN charindex(' ', YourColumn) = 0 THEN 
    LEN(YourColumn) ELSE charindex(' ', YourColumn) - 1 END)

How to open a different activity on recyclerView item onclick

The problem occurs in declaring context, while using Glide for ImageView or While using intent in recyclerview for item onClick. I Found this working for me which helps me to Declare context to use in Glide or Intent or Toast.

public class NoteAdapter extends FirestoreRecyclerAdapter<Note,NoteAdapter.NoteHolder> {

Context context;

public NoteAdapter(@NonNull FirestoreRecyclerOptions<Note> options) {
    super(options);
}

@Override
protected void onBindViewHolder(@NonNull NoteHolder holder, int position, @NonNull Note model) {
    holder.r_tv.setText(model.getTitle());
    Glide.with(CategoryActivity.context).load(model.getImage()).into(holder.r_iv);

    context = holder.itemView.getContext();

    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(context, SuggestActivity.class);
            context.startActivity(i);
        }
    });

}

@NonNull
@Override
public NoteHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_category,parent,false);

    return new NoteHolder(v);
}

public static class NoteHolder extends RecyclerView.ViewHolder
{
    TextView r_tv;
    ImageView r_iv;

    public NoteHolder(@NonNull View itemView) {
        super(itemView);

        r_tv = itemView.findViewById(R.id.r_tv);
        r_iv = itemView.findViewById(R.id.r_iv);


    }
}
}

How to add an extra row to a pandas dataframe

Upcoming pandas 0.13 version will allow to add rows through loc on non existing index data. However, be aware that under the hood, this creates a copy of the entire DataFrame so it is not an efficient operation.

Description is here and this new feature is called Setting With Enlargement.

How to create an Explorer-like folder browser control?

It's not as easy as it seems to implement a control like that. Explorer works with shell items, not filesystem items (ex: the control panel, the printers folder, and so on). If you need to implement it i suggest to have a look at the Windows shell functions at http://msdn.microsoft.com/en-us/library/bb776426(VS.85).aspx.

How to remove html special chars?

What I have done was to use: html_entity_decode, then use strip_tags to removed them.

Converting a String array into an int Array in java

private void processLine(String[] strings) {
    Integer[] intarray=new Integer[strings.length];
    for(int i=0;i<strings.length;i++) {
        intarray[i]=Integer.parseInt(strings[i]);
    }
    for(Integer temp:intarray) {
        System.out.println("convert int array from String"+temp);
    }
}

Display A Popup Only Once Per User

The best solution is to save a Boolean value in the database and then obtain that value and validate whether or not the modal was opened for that user, this value could be in the user table for example.

How to retrieve GET parameters from JavaScript

If you are using AngularJS, you can use $routeParams using ngRoute module

You have to add a module to your app

angular.module('myApp', ['ngRoute'])

Now you can use service $routeParams:

.controller('AppCtrl', function($routeParams) {
  console.log($routeParams); // JSON object
}

How to map calculated properties with JPA and Hibernate

You have three options:

  • either you are calculating the attribute using a @Transient method
  • you can also use @PostLoad entity listener
  • or you can use the Hibernate specific @Formula annotation

While Hibernate allows you to use @Formula, with JPA, you can use the @PostLoad callback to populate a transient property with the result of some calculation:

@Column(name = "price")
private Double price;

@Column(name = "tax_percentage")
private Double taxes;

@Transient
private Double priceWithTaxes;

@PostLoad
private void onLoad() {
    this.priceWithTaxes = price * taxes;
}

So, you can use the Hibernate @Formula like this:

@Formula("""
    round(
       (interestRate::numeric / 100) *
       cents *
       date_part('month', age(now(), createdOn)
    )
    / 12)
    / 100::numeric
    """)
private double interestDollars;

How can I close a Twitter Bootstrap popover with a click from anywhere (else) on the page?

$('.popForm').popover();

$('.conteneurPopForm').on("click",".fermePopover",function(){
    $(".popForm").trigger("click");
});

To be clear, just trigger the popover

Intellij reformat on file save

Below is Neil's answer updated.

IntelliJ 13 Steps:

  1. Code -> Reformat Code enter image description here
  2. Edit -> Macros -> Start Macro Recording
  3. Code -> Reformat Code
  4. File -> Save all
  5. Edit -> Macros -> Stop Macro Recording
  6. Name the macro (something like "formatted save")
  7. File -> Settings -> Keymap
  8. Right click on the macro. Add Keyboard Shortcut. Set the keyboard shortcut to Control + S. enter image description here
  9. IntelliJ will inform you of a hotkey conflict. Select "remove" to remove other assignments.

What are the differences between git remote prune, git prune, git fetch --prune, etc

git remote prune and git fetch --prune do the same thing: deleting the refs to the branches that don't exist on the remote, as you said. The second command connects to the remote and fetches its current branches before pruning.

However it doesn't touch the local branches you have checked out, that you can simply delete with

git branch -d  random_branch_I_want_deleted

Replace -d by -D if the branch is not merged elsewhere

git prune does something different, it purges unreachable objects, those commits that aren't reachable in any branch or tag, and thus not needed anymore.

Set Windows process (or user) memory limit

No way to do this that I know of, although I'm very curious to read if anyone has a good answer. I have been thinking about adding something like this to one of the apps my company builds, but have found no good way to do it.

The one thing I can think of (although not directly on point) is that I believe you can limit the total memory usage for a COM+ application in Windows. It would require the app to be written to run in COM+, of course, but it's the closest way I know of.

The working set stuff is good (Job Objects also control working sets), but that's not total memory usage, only real memory usage (paged in) at any one time. It may work for what you want, but afaik it doesn't limit total allocated memory.

insert datetime value in sql database with c#

It's more standard to use the format yyyy-mm-dd hh:mm:ss (IE: 2009-06-23 19:30:20)

Using that you won't have to worry about the format of the date (MM/DD/YYYY or DD/MM/YYYY). It will work with all of them.

Edit and replay XHR chrome/firefox etc?

Microsoft Chromium-based Edge supports "Edit and Replay" requests in the Network Tab as an experimental feature:

enter image description here

More details about the feature and how to enable it can be found here

C# - using List<T>.Find() with custom objects

Previous answers don't account for the fact that you've overloaded the equals operator and are using that to test for the sought element. In that case, your code would look like this:

list.Find(x => x == objectToFind);

Or, if you don't like lambda syntax, and have overriden object.Equals(object) or have implemented IEquatable<T>, you could do this:

list.Find(objectToFind.Equals);

How to change the style of a DatePicker in android?

Try this. It's the easiest & most efficient way

<style name="datepicker" parent="Theme.AppCompat.Light.Dialog">
        <item name="colorPrimary">@color/primary</item>
        <item name="colorPrimaryDark">@color/primary_dark</item>
        <item name="colorAccent">@color/primary</item>
</style>

Bring a window to the front in WPF

The problem could be that the thread calling your code from the hook hasn't been initialized by the runtime so calling runtime methods don't work.

Perhaps you could try doing an Invoke to marshal your code on to the UI thread to call your code that brings the window to the foreground.

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

Beyond the problematic use of async as pointed out by @Servy, the other issue is that you need to explicitly get T from Task<T> by calling Task.Result. Note that the Result property will block async code, and should be used carefully.

Try:

private async void button1_Click(object sender, EventArgs e)
{
    var s = await methodAsync();
    MessageBox.Show(s.Result);
}

How to make the division of 2 ints produce a float instead of another int?

Just cast one of the two operands to a float first.

v = (float)s / t;

The cast has higher precedence than the division, so happens before the division.

The other operand will be effectively automatically cast to a float by the compiler because the rules say that if either operand is of floating point type then the operation will be a floating point operation, even if the other operand is integral. Java Language Specification, §4.2.4 and §15.17

How to install pip3 on Windows?

There is another way to install the pip3: just reinstall 3.6.

Getting and removing the first character of a string

substring is definitely best, but here's one strsplit alternative, since I haven't seen one yet.

> x <- 'hello stackoverflow'
> strsplit(x, '')[[1]][1]
## [1] "h"

or equivalently

> unlist(strsplit(x, ''))[1]
## [1] "h"

And you can paste the rest of the string back together.

> paste0(strsplit(x, '')[[1]][-1], collapse = '')
## [1] "ello stackoverflow"

How can I manually set an Angular form field as invalid?

Adding to Julia Passynkova's answer

To set validation error in component:

formData.form.controls['email'].setErrors({'incorrect': true});

To unset validation error in component:

formData.form.controls['email'].setErrors(null);

Be careful with unsetting the errors using null as this will overwrite all errors. If you want to keep some around you may have to check for the existence of other errors first:

if (isIncorrectOnlyError){
   formData.form.controls['email'].setErrors(null);
}

converting list to json format - quick and easy way

I've done something like before using the JavaScript serialization class:

using System.Web.Script.Serialization;

And:

JavaScriptSerializer jss = new JavaScriptSerializer();

string output = jss.Serialize(ListOfMyObject);
Response.Write(output);
Response.Flush();
Response.End();

Unable to install packages in latest version of RStudio and R Version.3.1.1

Based on answers from the community, there appear to be several ways that might solve this:

  1. From the official FAQ and support forums and this answer, you may have have a firewall or proxy issue that is blocking RStudio from connecting to the internet:
  • Disable any firewalls
  • Tools -> Global Options -> Packages and unchecking the "Use Internet Explorer library/proxy for HTTP" option and restart R (#1, #2, #3)
  • Flag R with --internet2
  • On CentOS it was suggested to try the following: install.packages('package_name', dependencies=TRUE, repos='http://cran.rstudio.com/')
  1. Several answers suggest using an alternate mirror (#1, #2, #3):
  • Preferences > General > Default working directory > Browse and switch your mirror from local/global (whichever is unchecked)
  1. On Windows you can start the application with http_proxy=http://host:port/:
  • "C:\Program Files\RStudio\bin\rstudio.exe" http_proxy=http://host:port/
  1. Shut down and restart. Needed after many of the above operations, and suggested standalone.

Java Spring - How to use classpath to specify a file location?

looks like you have maven project and so resources are in classpath by

go for

getClass().getResource("classpath:storedProcedures.sql")

how to get the last part of a string before a certain character?

You are looking for str.rsplit(), with a limit:

print x.rsplit('-', 1)[0]

.rsplit() searches for the splitting string from the end of input string, and the second argument limits how many times it'll split to just once.

Another option is to use str.rpartition(), which will only ever split just once:

print x.rpartition('-')[0]

For splitting just once, str.rpartition() is the faster method as well; if you need to split more than once you can only use str.rsplit().

Demo:

>>> x = 'http://test.com/lalala-134'
>>> print x.rsplit('-', 1)[0]
http://test.com/lalala
>>> 'something-with-a-lot-of-dashes'.rsplit('-', 1)[0]
'something-with-a-lot-of'

and the same with str.rpartition()

>>> print x.rpartition('-')[0]
http://test.com/lalala
>>> 'something-with-a-lot-of-dashes'.rpartition('-')[0]
'something-with-a-lot-of'

Why does my JavaScript code receive a "No 'Access-Control-Allow-Origin' header is present on the requested resource" error, while Postman does not?

Because
$.ajax({type: "POST" - calls OPTIONS
$.post( - Calls POST

Both are different. Postman calls "POST" properly, but when we call it, it will be "OPTIONS".

For C# web services - Web API

Please add the following code in your web.config file under <system.webServer> tag. This will work:

<httpProtocol>
    <customHeaders>
        <add name="Access-Control-Allow-Origin" value="*" />
    </customHeaders>
</httpProtocol>

Please make sure you are not doing any mistake in the Ajax call

jQuery

$.ajax({
    url: 'http://mysite.microsoft.sample.xyz.com/api/mycall',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded'
    },
    type: "POST", /* or type:"GET" or type:"PUT" */
    dataType: "json",
    data: {
    },
    success: function (result) {
        console.log(result);
    },
    error: function () {
        console.log("error");
    }
});

Note: If you are looking for downloading content from a third-party website then this will not help you. You can try the following code, but not JavaScript.

System.Net.WebClient wc = new System.Net.WebClient();
string str = wc.DownloadString("http://mysite.microsoft.sample.xyz.com/api/mycall");

Class file has wrong version 52.0, should be 50.0

In your IntelliJ idea find tools.jar replace it with tools.jar from yout JDK8

Default port for SQL Server

  1. The default SQL Server port is 1433 but only if it's a default install. Named instances get a random port number.

  2. The browser service runs on port UDP 1434.

  3. Reporting services is a web service - so it's port 80, or 443 if it's SSL enabled.

  4. Analysis services is 2382 but only if it's a default install. Named instances get a random port number.

Iterating through a variable length array

for(int i = 0; i < array.length; i++)
{
    System.out.println(array[i]);
}

or

for(String value : array)
{
    System.out.println(value);
}

The second version is a "for-each" loop and it works with arrays and Collections. Most loops can be done with the for-each loop because you probably don't care about the actual index. If you do care about the actual index us the first version.

Just for completeness you can do the while loop this way:

int index = 0;

while(index < myArray.length)
{
  final String value;

  value = myArray[index];
  System.out.println(value);
  index++;
}

But you should use a for loop instead of a while loop when you know the size (and even with a variable length array you know the size... it is just different each time).

How to horizontally center an unordered list of unknown width?

Try wrapping the list in a div and give that div the inline property instead of your list.