Programs & Examples On #Advertisement server

How to copy an object by value, not by reference

what language is this? If you're using a language that passes everything by reference like Java (except for native types), typically you can call .clone() method. The .clone() method is typically implemented by copying/cloning all relevant instance fields into the new object.

Best Practices: working with long, multiline strings in PHP?

The one who believes that

"abc\n" . "def\n"

is multiline string is wrong. That's two strings with concatenation operator, not a multiline string. Such concatenated strings cannot be used as keys of pre-defined arrays, for example. Unfortunately php does not offer real multiline strings in form of

"abc\n"
"def\n"

only HEREDOC and NOWDOC syntax, which is more suitable for templates, because nested code indent is broken by such syntax.

How to get process ID of background process?

this is what I have done. Check it out, hope it can help.

#!/bin/bash
#
# So something to show.
echo "UNO" >  UNO.txt
echo "DOS" >  DOS.txt
#
# Initialize Pid List
dPidLst=""
#
# Generate background processes
tail -f UNO.txt&
dPidLst="$dPidLst $!"
tail -f DOS.txt&
dPidLst="$dPidLst $!"
#
# Report process IDs
echo PID=$$
echo dPidLst=$dPidLst
#
# Show process on current shell
ps -f
#
# Start killing background processes from list
for dPid in $dPidLst
do
        echo killing $dPid. Process is still there.
        ps | grep $dPid
        kill $dPid
        ps | grep $dPid
        echo Just ran "'"ps"'" command, $dPid must not show again.
done

Then just run it as: ./bgkill.sh with proper permissions of course

root@umsstd22 [P]:~# ./bgkill.sh
PID=23757
dPidLst= 23758 23759
UNO
DOS
UID        PID  PPID  C STIME TTY          TIME CMD
root      3937  3935  0 11:07 pts/5    00:00:00 -bash
root     23757  3937  0 11:55 pts/5    00:00:00 /bin/bash ./bgkill.sh
root     23758 23757  0 11:55 pts/5    00:00:00 tail -f UNO.txt
root     23759 23757  0 11:55 pts/5    00:00:00 tail -f DOS.txt
root     23760 23757  0 11:55 pts/5    00:00:00 ps -f
killing 23758. Process is still there.
23758 pts/5    00:00:00 tail
./bgkill.sh: line 24: 23758 Terminated              tail -f UNO.txt
Just ran 'ps' command, 23758 must not show again.
killing 23759. Process is still there.
23759 pts/5    00:00:00 tail
./bgkill.sh: line 24: 23759 Terminated              tail -f DOS.txt
Just ran 'ps' command, 23759 must not show again.
root@umsstd22 [P]:~# ps -f
UID        PID  PPID  C STIME TTY          TIME CMD
root      3937  3935  0 11:07 pts/5    00:00:00 -bash
root     24200  3937  0 11:56 pts/5    00:00:00 ps -f

Is there a code obfuscator for PHP?

People will offer you obfuscators, but no amount of obfuscation can prevent someone from getting at your code. None. If your computer can run it, or in the case of movies and music if it can play it, the user can get at it. Even compiling it to machine code just makes the job a little more difficult. If you use an obfuscator, you are just fooling yourself. Worse, you're also disallowing your users from fixing bugs or making modifications.

Music and movie companies haven't quite come to terms with this yet, they still spend millions on DRM.

In interpreted languages like PHP and Perl it's trivial. Perl used to have lots of code obfuscators, then we realized you can trivially decompile them.

perl -MO=Deparse some_program

PHP has things like DeZender and Show My Code.

My advice? Write a license and get a lawyer. The only other option is to not give out the code and instead run a hosted service.

See also the perlfaq entry on the subject.

How to create a new schema/new user in Oracle Database 11g?

SQL> select Username from dba_users
  2  ;

USERNAME
------------------------------
SYS
SYSTEM
ANONYMOUS
APEX_PUBLIC_USER
FLOWS_FILES
APEX_040000
OUTLN
DIP
ORACLE_OCM
XS$NULL
MDSYS

USERNAME
------------------------------
CTXSYS
DBSNMP
XDB
APPQOSSYS
HR

16 rows selected.

SQL> create user testdb identified by password;

User created.

SQL> select username from dba_users;

USERNAME
------------------------------
TESTDB
SYS
SYSTEM
ANONYMOUS
APEX_PUBLIC_USER
FLOWS_FILES
APEX_040000
OUTLN
DIP
ORACLE_OCM
XS$NULL

USERNAME
------------------------------
MDSYS
CTXSYS
DBSNMP
XDB
APPQOSSYS
HR

17 rows selected.

SQL> grant create session to testdb;

Grant succeeded.

SQL> create tablespace testdb_tablespace
  2  datafile 'testdb_tabspace.dat'
  3  size 10M autoextend on;

Tablespace created.

SQL> create temporary tablespace testdb_tablespace_temp
  2  tempfile 'testdb_tabspace_temp.dat'
  3  size 5M autoextend on;

Tablespace created.

SQL> drop user testdb;

User dropped.

SQL> create user testdb
  2  identified by password
  3  default tablespace testdb_tablespace
  4  temporary tablespace testdb_tablespace_temp;

User created.

SQL> grant create session to testdb;

Grant succeeded.

SQL> grant create table to testdb;

Grant succeeded.

SQL> grant unlimited tablespace to testdb;

Grant succeeded.

SQL>

how to remove the bold from a headline?

<h1><span style="font-weight:bold;">THIS IS</span> A HEADLINE</h1>

But be sure that h1 is marked with

font-weight:normal;

You can also set the style with a id or class attribute.

How to escape JSON string?

I would also recommend using the JSON.NET library mentioned, but if you have to escape unicode characters (e.g. \uXXXX format) in the resulting JSON string, you may have to do it yourself. Take a look at Converting Unicode strings to escaped ascii string for an example.

deleting rows in numpy array

This is similar to your original approach, and will use less space than unutbu's answer, but I suspect it will be slower.

>>> import numpy as np
>>> p = np.array([[1.5, 0], [1.4,1.5], [1.6, 0], [1.7, 1.8]])
>>> p
array([[ 1.5,  0. ],
       [ 1.4,  1.5],
       [ 1.6,  0. ],
       [ 1.7,  1.8]])
>>> nz = (p == 0).sum(1)
>>> q = p[nz == 0, :]
>>> q
array([[ 1.4,  1.5],
       [ 1.7,  1.8]])

By the way, your line p.delete() doesn't work for me - ndarrays don't have a .delete attribute.

How to retrieve the current version of a MySQL database management system (DBMS)?

For Mac,

  1. login to mysql server.

  2. execute the following command:

     SHOW VARIABLES LIKE "%version%";
    

Accessing MVC's model property from Javascript

try this: (you missed the single quotes)

var floorplanSettings = '@Html.Raw(Json.Encode(Model.FloorPlanSettings))';

clearing select using jquery

$('option', '#theSelect').remove();

How to call a asp:Button OnClick event using JavaScript?

Set style= "display:none;". By setting visible=false, it will not render button in the browser. Thus,client side script wont execute.

<asp:Button ID="savebtn" runat="server" OnClick="savebtn_Click" style="display:none" />

html markup should be

<button id="btnsave" onclick="fncsave()">Save</button>

Change javascript to

<script type="text/javascript">
     function fncsave()
     {
        document.getElementById('<%= savebtn.ClientID %>').click();
     }
</script>

Using bind variables with dynamic SELECT INTO clause in PL/SQL

No you can't use bind variables that way. In your second example :into_bind in v_query_str is just a placeholder for value of variable v_num_of_employees. Your select into statement will turn into something like:

SELECT COUNT(*) INTO  FROM emp_...

because the value of v_num_of_employees is null at EXECUTE IMMEDIATE.

Your first example presents the correct way to bind the return value to a variable.

Edit

The original poster has edited the second code block that I'm referring in my answer to use OUT parameter mode for v_num_of_employees instead of the default IN mode. This modification makes the both examples functionally equivalent.

PHP: If internet explorer 6, 7, 8 , or 9

Checking for MSIE only is not enough to detect IE. You need also "Trident" which is only used in IE11. So here is my solution which worked an versions 8 to 11.

$agent=strtoupper($_SERVER['HTTP_USER_AGENT']);
$isIE=(strpos($agent,'MSIE')!==false || strpos($agent,'TRIDENT')!==false);

How to replace captured groups only?

A little improvement to Matthew's answer could be a lookahead instead of the last capturing group:

.replace(/(\w+)(\d+)(?=\w+)/, "$1!NEW_ID!");

Or you could split on the decimal and join with your new id like this:

.split(/\d+/).join("!NEW_ID!");

Example/Benchmark here: https://codepen.io/jogai/full/oyNXBX

Django 1.7 - "No migrations to apply" when run migrate after makemigrations

if you are using GIT for control versions and in some of yours commit you added db.sqlite3, GIT will keep some references of the database, so when you execute 'python manage.py migrate', this reference will be reflected on the new database. I recommend to execute the following command:

git filter-branch --index-filter "git rm -rf --cached --ignore-unmatch 'db.sqlite3' HEAD

it worked for me :)

Enable PHP Apache2

You can use a2enmod or a2dismod to enable/disable modules by name.

From terminal, run: sudo a2enmod php5 to enable PHP5 (or some other module), then sudo service apache2 reload to reload the Apache2 configuration.

How to get the cursor to change to the hand when hovering a <button> tag

Just add this style:

cursor: pointer;

The reason it's not happening by default is because most browsers reserve the pointer for links only (and maybe a couple other things I'm forgetting, but typically not <button>s).

More on the cursor property: https://developer.mozilla.org/en/CSS/cursor

I usually apply this to <button> and <label> by default.

NOTE: I just caught this:

the button tags have an id of #more

It's very important that each element has it's own unique id, you cannot have duplicates. Use the class attribute instead, and change your selector from #more to .more. This is actually quite a common mistake that is the cause of many problems and questions asked here. The earlier you learn how to use id, the better.

Vim clear last search highlighting

You can alternatively add mapping on your .vimrc file as,

nmap <C-N> :nohlsearch

and then you can press

Ctrl+N

to anytime to clear the highlighted text

C# refresh DataGridView when updating or inserted on another form

DataGridView.Refresh and And DataGridView.Update are methods that are inherited from Control. They have to do with redrawing the control which is why new rows don't appear.

My guess is the data retrieval is on the Form_Load. If you want your Button on Form B to retrieve the latest data from the database then that's what you have to do whatever Form_Load is doing.

A nice way to do that is to separate your data retrieval calls into a separate function and call it from both the From Load and Button Click events.

The transaction manager has disabled its support for remote/network transactions

I had the same error message. For me changing pooling=False to ;pooling=true;Max Pool Size=200 in the connection string fixed the problem.

Get Android Device Name

Following works for me.

String deviceName = Settings.Global.getString(.getContentResolver(), Settings.Global.DEVICE_NAME);

I don't think so its duplicate answer. The above ppl are talking about Setting Secure, for me setting secure is giving null, if i use setting global it works. Thanks anyways.

How do I get the base URL with PHP?

Fun 'base_url' snippet!

if (!function_exists('base_url')) {
    function base_url($atRoot=FALSE, $atCore=FALSE, $parse=FALSE){
        if (isset($_SERVER['HTTP_HOST'])) {
            $http = isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) !== 'off' ? 'https' : 'http';
            $hostname = $_SERVER['HTTP_HOST'];
            $dir =  str_replace(basename($_SERVER['SCRIPT_NAME']), '', $_SERVER['SCRIPT_NAME']);

            $core = preg_split('@/@', str_replace($_SERVER['DOCUMENT_ROOT'], '', realpath(dirname(__FILE__))), NULL, PREG_SPLIT_NO_EMPTY);
            $core = $core[0];

            $tmplt = $atRoot ? ($atCore ? "%s://%s/%s/" : "%s://%s/") : ($atCore ? "%s://%s/%s/" : "%s://%s%s");
            $end = $atRoot ? ($atCore ? $core : $hostname) : ($atCore ? $core : $dir);
            $base_url = sprintf( $tmplt, $http, $hostname, $end );
        }
        else $base_url = 'http://localhost/';

        if ($parse) {
            $base_url = parse_url($base_url);
            if (isset($base_url['path'])) if ($base_url['path'] == '/') $base_url['path'] = '';
        }

        return $base_url;
    }
}

Use as simple as:

//  url like: http://stackoverflow.com/questions/2820723/how-to-get-base-url-with-php

echo base_url();    //  will produce something like: http://stackoverflow.com/questions/2820723/
echo base_url(TRUE);    //  will produce something like: http://stackoverflow.com/
echo base_url(TRUE, TRUE); || echo base_url(NULL, TRUE);    //  will produce something like: http://stackoverflow.com/questions/
//  and finally
echo base_url(NULL, NULL, TRUE);
//  will produce something like: 
//      array(3) {
//          ["scheme"]=>
//          string(4) "http"
//          ["host"]=>
//          string(12) "stackoverflow.com"
//          ["path"]=>
//          string(35) "/questions/2820723/"
//      }

jQuery - Fancybox: But I don't want scrollbars!

I know this sounds a bit weird but have any of you tried to set the margin of the form page body tag to 0.

The problem is actually pretty simple, the reason is that the body tag margin by default is set to 8px (depending on browser) and if you just set it to 0 then it fixes the scrollbar.

The js configuration I have is as follows and it works well without changing the css of fancybox.

$(".iframe").fancybox({
    'autoScale'         : false,
    'autoDimensions'    : false,
    'transitionIn'      : 'none',
    'transitionOut'     : 'none',
    'type'              : 'iframe'
});

Python "expected an indented block"

in python .....intendation matters, e.g.:

if a==1:
    print("hey")

if a==2:
   print("bye")

print("all the best")

In this case "all the best" will be printed if either of the two conditions executes, but if it would have been like this

if a==2:
   print("bye")
   print("all the best")

then "all the best" will be printed only if a==2

Mutex lock threads

Q1.) Assuming process B tries to take ownership of the same mutex you locked in process A (you left that out of your pseudocode) then no, process B cannot access sharedResource while the mutex is locked since it will sit waiting to lock the mutex until it is released by process A. It will return from the mutex_lock() function when the mutex is locked (or when an error occurs!)

Q2.) In Process B, ensure you always lock the mutex, access the shared resource, and then unlock the mutex. Also, check the return code from the mutex_lock( pMutex ) routine to ensure that you actually own the mutex, and ONLY unlock the mutex if you have locked it. Do the same from process A.

Both processes should basically do the same thing when accessing the mutex.
lock() If the lock succeeds, then { access sharedResource unlock() }

Q3.) Yes, there are lots of diagrams: =) https://www.google.se/search?q=mutex+thread+process&rlz=1C1AFAB_enSE487SE487&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=ErodUcSmKqf54QS6nYDoAw&biw=1200&bih=1730&sei=FbodUbPbB6mF4ATarIBQ

MySQL Select all columns from one table and some from another table

select a.* , b.Aa , b.Ab, b.Ac from table1 a left join table2 b on a.id=b.id

this should select all columns from table 1 and only the listed columns from table 2 joined by id.

Export a list into a CSV or TXT file in R

You can simply wrap your list as a data.frame (data.frame is in fact a special kind of list). Here is an example:

mylist = list() 
mylist[["a"]] = 1:10 
mylist[["b"]] = letters[1:10]
write.table(as.data.frame(mylist),file="mylist.csv", quote=F,sep=",",row.names=F)

or alternatively you can use write.csv (a wrapper around write.table). For the conversion of the list , you can use both as.data.frame(mylist) and data.frame(mylist).

To help in making a reproducible example, you can use functions like dput on your data.

R color scatter plot points based on values

Best thing to do here is to add a column to the data object to represent the point colour. Then update sections of it by filtering.

data<- read.table('sample_data.txtt', header=TRUE, row.name=1)
# Create new column filled with default colour
data$Colour="black"
# Set new column values to appropriate colours
data$Colour[data$col_name2>=3]="red"
data$Colour[data$col_name2<=1]="blue"
# Plot all points at once, using newly generated colours
plot(data$col_name1,data$col_name2, ylim=c(0,5), col=data$Colour, ylim=c(0,10))

It should be clear how to adapt this for plots with more colours & conditions.

How do I convert a file path to a URL in ASP.NET

The problem with all these answers is that they do not take virtual directories into account.

Consider:

Site named "tempuri.com/" rooted at c:\domains\site
virtual directory "~/files" at c:\data\files
virtual directory "~/files/vip" at c:\data\VIPcust\files

So:

Server.MapPath("~/files/vip/readme.txt") 
  = "c:\data\VIPcust\files\readme.txt"

But there is no way to do this:

MagicResolve("c:\data\VIPcust\files\readme.txt") 
   = "http://tempuri.com/files/vip/readme.txt"

because there is no way to get a complete list of virtual directories.

how to check the jdk version used to compile a .class file

Does the -verbose flag to your java command yield any useful info? If not, maybe java -X reveals something specific to your version that might help?

How to do tag wrapping in VS code?

As I can't comment, I'll expand on Alex's fantastic answer.

If you want the Sublime-like experience with wrapping open up the Keymap Extensions (Preferences > Keymap Extensions [Cmd+K Cmd+M]) and add the following object:

{
    "key": "alt+w",
    "command": "editor.emmet.action.wrapIndividualLinesWithAbbreviation",
    "when": "editorHasSelection && editorTextFocus"
}

Which will bind the Emmet wrap command to Alt+W when text is selected

(Sorry for OSX only instructions)

PHPMyAdmin Default login password

This is asking for your MySQL username and password.

You should enter these details, which will default to "root" and "" (i.e.: nothing) if you've not specified a password.

Change Tomcat Server's timeout in Eclipse

Open the Servers view -> double click tomcat -> drop down the Timeouts section

There you can increase the startup time for each particular server.

Run cron job only if it isn't already running

As a follow up to Earlz answer, you need a wrapper script that creates a $PID.running file when it starts, and delete when it ends. The wrapper script calls the script you wish to run. The wrapper is necessary in case the target script fails or errors out, the pid file gets deleted..

How do I clear the previous text field value after submitting the form with out refreshing the entire page?

I had that issue and I solved by doing this:

.done(function() {
                    $(this).find("input").val("");
                    $("#feedback").trigger("reset");
                });

I added this code after my script as I used jQuery. Try same)

<script type="text/JavaScript">

        $(document).ready(function() {
            $("#feedback").submit(function(event) {
                event.preventDefault();
                $.ajax({
                    url: "feedback_lib.php",
                    type: "post",
                    data: $("#feedback").serialize()
                }).done(function() {
                    $(this).find("input").val("");
                    $("#feedback").trigger("reset");
                });
            });
        });
    </script>
    <form id="feedback" action="" name="feedback" method="post">
        <input id="name" name="name" placeholder="name" />
        <br />
        <input id="surname" name="surname" placeholder="surname" />
        <br />
        <input id="enquiry" name="enquiry" placeholder="enquiry" />
        <br />
        <input id="organisation" name="organisation" placeholder="organisation" />
        <br />
        <input id="email" name="email" placeholder="email" />
        <br />
        <textarea id="message" name="message" rows="7" cols="40" placeholder="?????????"></textarea>
        <br />
        <button id="send" name="send">send</button>
    </form>

How to subscribe to an event on a service in Angular2?

Update: I have found a better/proper way to solve this problem using a BehaviorSubject or an Observable rather than an EventEmitter. Please see this answer: https://stackoverflow.com/a/35568924/215945

Also, the Angular docs now have a cookbook example that uses a Subject.


Original/outdated/wrong answer: again, don't use an EventEmitter in a service. That is an anti-pattern.

Using beta.1... NavService contains the EventEmiter. Component Navigation emits events via the service, and component ObservingComponent subscribes to the events.

nav.service.ts

import {EventEmitter} from 'angular2/core';
export class NavService {
  navchange: EventEmitter<number> = new EventEmitter();
  constructor() {}
  emitNavChangeEvent(number) {
    this.navchange.emit(number);
  }
  getNavChangeEmitter() {
    return this.navchange;
  }
}

components.ts

import {Component} from 'angular2/core';
import {NavService} from '../services/NavService';

@Component({
  selector: 'obs-comp',
  template: `obs component, item: {{item}}`
})
export class ObservingComponent {
  item: number = 0;
  subscription: any;
  constructor(private navService:NavService) {}
  ngOnInit() {
    this.subscription = this.navService.getNavChangeEmitter()
      .subscribe(item => this.selectedNavItem(item));
  }
  selectedNavItem(item: number) {
    this.item = item;
  }
  ngOnDestroy() {
    this.subscription.unsubscribe();
  }
}

@Component({
  selector: 'my-nav',
  template:`
    <div class="nav-item" (click)="selectedNavItem(1)">nav 1 (click me)</div>
    <div class="nav-item" (click)="selectedNavItem(2)">nav 2 (click me)</div>
  `,
})
export class Navigation {
  item = 1;
  constructor(private navService:NavService) {}
  selectedNavItem(item: number) {
    console.log('selected nav item ' + item);
    this.navService.emitNavChangeEvent(item);
  }
}

Plunker

How to clear the canvas for redrawing

If you are drawing lines, make sure you don't forget:

context.beginPath();

Otherwise the lines won't get cleared.

Android Get Application's 'Home' Data Directory

Of course, never fails. Found the solution about a minute after posting the above question... solution for those that may have had the same issue:

ContextWrapper.getFilesDir()

Found here.

How do I set up a private Git repository on GitHub? Is it even possible?

GitHub is a great tool in-all for making repositories. However, it does not do good with private repositories.

You're forced to pay for private repositories unless you get some sort of plan. I have a couple of projects so far, and if GitHub doesn't do what I want I just go to Bitbucket. It's a bit harder to work with than GitHub, however it's unlimited free repositories.

Display open transactions in MySQL

How can I display these open transactions and commit or cancel them?

There is no open transaction, MySQL will rollback the transaction upon disconnect.
You cannot commit the transaction (IFAIK).

You display threads using

SHOW FULL PROCESSLIST  

See: http://dev.mysql.com/doc/refman/5.1/en/thread-information.html

It will not help you, because you cannot commit a transaction from a broken connection.

What happens when a connection breaks
From the MySQL docs: http://dev.mysql.com/doc/refman/5.0/en/mysql-tips.html

4.5.1.6.3. Disabling mysql Auto-Reconnect

If the mysql client loses its connection to the server while sending a statement, it immediately and automatically tries to reconnect once to the server and send the statement again. However, even if mysql succeeds in reconnecting, your first connection has ended and all your previous session objects and settings are lost: temporary tables, the autocommit mode, and user-defined and session variables. Also, any current transaction rolls back.

This behavior may be dangerous for you, as in the following example where the server was shut down and restarted between the first and second statements without you knowing it:

Also see: http://dev.mysql.com/doc/refman/5.0/en/auto-reconnect.html

How to diagnose and fix this
To check for auto-reconnection:

If an automatic reconnection does occur (for example, as a result of calling mysql_ping()), there is no explicit indication of it. To check for reconnection, call mysql_thread_id() to get the original connection identifier before calling mysql_ping(), then call mysql_thread_id() again to see whether the identifier has changed.

Make sure you keep your last query (transaction) in the client so that you can resubmit it if need be.
And disable auto-reconnect mode, because that is dangerous, implement your own reconnect instead, so that you know when a drop occurs and you can resubmit that query.

JSON character encoding

If you're using StringEntity try this, using your choice of character encoding. It handles foreign characters as well.

Enum "Inheritance"

Alternative solution

In my company, we avoid "jumping over projects" to get to non-common lower level projects. For instance, our presentation/API layer can only reference our domain layer, and the domain layer can only reference the data layer.

However, this is a problem when there are enums that need to be referenced by both the presentation and the domain layers.

Here is the solution that we have implemented (so far). It is a pretty good solution and works well for us. The other answers were hitting all around this.

The basic premise is that enums cannot be inherited - but classes can. So...

// In the lower level project (or DLL)...
public abstract class BaseEnums
{
    public enum ImportanceType
    {
        None = 0,
        Success = 1,
        Warning = 2,
        Information = 3,
        Exclamation = 4
    }

    [Flags]
    public enum StatusType : Int32
    {
        None = 0,
        Pending = 1,
        Approved = 2,
        Canceled = 4,
        Accepted = (8 | Approved),
        Rejected = 16,
        Shipped = (32 | Accepted),
        Reconciled = (64 | Shipped)
    }

    public enum Conveyance
    {
        None = 0,
        Feet = 1,
        Automobile = 2,
        Bicycle = 3,
        Motorcycle = 4,
        TukTuk = 5,
        Horse = 6,
        Yak = 7,
        Segue = 8
    }

Then, to "inherit" the enums in another higher level project...

// Class in another project
public sealed class SubEnums: BaseEnums
{
   private SubEnums()
   {}
}

This has three real advantages...

  1. The enum definitions are automatically the same in both projects - by definition.
  2. Any changes to the enum definitions are automatically echoed in the second without having to make any modifications to the second class.
  3. The enums are based on the same code - so the values can easily be compared (with some caveats).

To reference the enums in the first project, you can use the prefix of the class: BaseEnums.StatusType.Pending or add a "using static BaseEnums;" statement to your usings.

In the second project when dealing with the inherited class however, I could not get the "using static ..." approach to work, so all references to the "inherited enums" would be prefixed with the class, e.g. SubEnums.StatusType.Pending. If anyone comes up with a way to allow the "using static" approach to be used in the second project, let me know.

I am sure that this can be tweaked to make it even better - but this actually works and I have used this approach in working projects.

Please up-vote this if you find it helpful.

Facebook api: (#4) Application request limit reached

now Application-Level Rate Limiting 200 calls per hour !

you can look this image.enter image description here

python request with authentication (access_token)

Have you tried the uncurl package (https://github.com/spulec/uncurl)? You can install it via pip, pip install uncurl. Your curl request returns:

>>> uncurl "curl --header \"Authorization:access_token myToken\" https://website.com/id"

requests.get("https://website.com/id",
    headers={
        "Authorization": "access_token myToken"
    },
    cookies={},
)

python - checking odd/even numbers and changing outputs on number size

Simple but yet fast:

>>> def is_odd(a):
...     return bool(a - ((a>>1)<<1))
...
>>> print(is_odd(13))
True
>>> print(is_odd(12))
False
>>>

Or even simpler:

>>> def is_odd(a):
...   return bool(a & 1)

jQuery and TinyMCE: textarea value doesn't submit

I used:

var save_and_add = function(){
    tinyMCE.triggerSave();
    $('.new_multi_text_block_item').submit();
};

This is all you need to do.

How can I display a modal dialog in Redux that performs asynchronous actions?

Wrap the modal into a connected container and perform the async operation in here. This way you can reach both the dispatch to trigger actions and the onClose prop too. To reach dispatch from props, do not pass mapDispatchToProps function to connect.

class ModalContainer extends React.Component {
  handleDelete = () => {
    const { dispatch, onClose } = this.props;
    dispatch({type: 'DELETE_POST'});

    someAsyncOperation().then(() => {
      dispatch({type: 'DELETE_POST_SUCCESS'});
      onClose();
    })
  }

  render() {
    const { onClose } = this.props;
    return <Modal onClose={onClose} onSubmit={this.handleDelete} />
  }
}

export default connect(/* no map dispatch to props here! */)(ModalContainer);

The App where the modal is rendered and its visibility state is set:

class App extends React.Component {
  state = {
    isModalOpen: false
  }

  handleModalClose = () => this.setState({ isModalOpen: false });

  ...

  render(){
    return (
      ...
      <ModalContainer onClose={this.handleModalClose} />  
      ...
    )
  }

}

Appending HTML string to the DOM

Is this acceptable?

var child = document.createElement('div');
child.innerHTML = str;
child = child.firstChild;
document.getElementById('test').appendChild(child);

jsFiddle.

But, Neil's answer is a better solution.

INSTALL_FAILED_USER_RESTRICTED : android studio using redmi 4 device

For MIUI 9.6 works:
1. Become a developer: Settings >> About phone >> MIUI version tap 7 times.

2. Again Settings >> Additional settings >> Developer options (turn on) >> USB debugging (turn on) >> Install via USB (turn on).

3. You will be asked for permission through your MI account. Confirm permission.

4. Note: During the installation of the application, your device will give you 7 seconds to confirm the installation. Don't miss it!

What does [object Object] mean? (JavaScript)

The alert() function can't output an object in a read-friendly manner. Try using console.log(object) instead, and fire up your browser's console to debug.

Fatal error: Call to undefined function mysqli_connect()

On Raspberry Pi I had to install php5 mysql extension.

apt-get install php5-mysql

After installing the client, the webserver should be restarted. In case you're using apache, the following should work:

sudo service apache2 restart

Launch an app from within another (iPhone)

In order to let you open your application from another, you'll need to make changes in both applications. Here are the steps using Swift 3 with iOS 10 update:

1. Register your application that you want to open

Update the Info.plist by defining your application's custom and unique URL Scheme.

enter image description here

Note that your scheme name should be unique, otherwise if you have another application with the same URL scheme name installed on your device, then this will be determined runtime which one gets opened.

2. Include the previous URL scheme in your main application

You'll need to specify the URL scheme you want the app to be able to use with the canOpenURL: method of the UIApplication class. So open the main application's Info.plist and add the other application's URL scheme to LSApplicationQueriesSchemes. (Introduced in iOS 9.0)

enter image description here

3. Implement the action that opens your application

Now everything is set up, so you're good to write your code in your main application that opens your other app. This should looks something like this:

let appURLScheme = "MyAppToOpen://"

guard let appURL = URL(string: appURLScheme) else {
    return
}

if UIApplication.shared.canOpenURL(appURL) {

    if #available(iOS 10.0, *) {
        UIApplication.shared.open(appURL)
    }
    else {
        UIApplication.shared.openURL(appURL)
    }
}
else {
    // Here you can handle the case when your other application cannot be opened for any reason.
}

Note that these changes requires a new release if you want your existing app (installed from AppStore) to open. If you want to open an application that you've already released to Apple AppStore, then you'll need to upload a new version first that includes your URL scheme registration.

Docker - Container is not running

For anyone attempting something similar using a Dockerfile...

Running in detached mode won't help. The container will always exit (stop running) if the command is non-blocking, this is the case with bash.

In this case, a workaround would be: 1. Commit the resulting image: (container_name = the name of the container you want to base the image off of, image_name = the name of the image to be created docker commit container_name image_name 2. Use docker run to create a new container using the new image, specifying the command you want to run. Here, I will run "bash": docker run -it image_name bash

This would get you the interactive login you're looking for.

Loaded nib but the 'view' outlet was not set

I ran into something very similar tonight, with a Swift UIViewController subclass. In this case, none of the above fixes worked, but reordering my code a bit did. Net-net, having an extension to the subclass occur before the subclass's definition itself in the same file seems to confuse XCode, despite compiling fine; the fix was to place the extensions after the subclass's definition.

I've posted the details in an answer to this similar question.

Error QApplication: no such file or directory

Please make sure that the version of qmake you are using corresponds to the version of QT you want to use.

To be sure, you can just run :

$qmake -v

Your problem seems to be a symptom of a version conflict between QT 3 and 4, as can be seen here :

http://lists.trolltech.com/qt4-preview-feedback/2005-11/thread00013-0.html

To fix this, you can either delete your old install of QT, or specifically point to qmake-qt4 in your Makefile.

An error occurred while executing the command definition. See the inner exception for details

Usually this means that your schema and mapping files are not in synch and there is a renamed or missing column someplace.

What does "./" (dot slash) refer to in terms of an HTML file path location?

. is a shorthand for the current directory and is used in Linux and Unix to execute a compiled program in the current directory. That is why you don't see this used in Web Development much except by open source, non-Windows frameworks like Google Angular which was written by people stuck on open source platforms.

./ also resolves to the current directory and is atypical in Web but supported as a path in some open source frameworks. Because it resolves the same as no path to the current file directory its not used. Example: ./image.jpg = image.jpg. Again, this is a relic of Unix operating systems that need path resolutions like this to run executables and resolve paths for security reasons. Its not a typical web path. That is why this syntax is redundant.

../ is a traditional web path that goes one directory up

/ is the ROOT of your website

These path resolutions below are true...

./folder= folder this is always true in web path resolution

./file.html = file.html this is always true in web path resolution

./ = {no path} an empty path is the same as ./ in the web world

{no path} = / an empty path is the same as the web root if your file is in the root directory

./ = / ONLY if you are in the root folder

../ = / ONLY if you are one folder below the web root

Disabling right click on images using jquery

For modern browsers all you need is this CSS:

img {
    pointer-events: none;
}

Older browsers will still allow pointer events on the images, but the CSS above will take care of the vast majority of visitors to your site, and used in conjunction with the contextmenu methods should give you a very solid solution.

How much RAM is SQL Server actually using?

Related to your question, you may want to consider limiting the amount of RAM SQL Server has access to if you are using it in a shared environment, i.e., on a server that hosts more than just SQL Server:

  1. Start > All Programs > Microsoft SQL Server 2005: SQL Server Management Studio.
  2. Connect using whatever account has admin rights.
  3. Right click on the database > Properties.
  4. Select "Memory" from the left pane and then change the "Server memory options" to whatever you feel should be allocated to SQL Server.

This will help alleviate SQL Server from consuming all the server's RAM.

Convert varchar2 to Date ('MM/DD/YYYY') in PL/SQL

First you convert VARCHAR to DATE and then back to CHAR. I do this almost every day and never found any better way.

select TO_CHAR(TO_DATE(DOJ,'MM/DD/YYYY'), 'MM/DD/YYYY') from EmpTable

What does axis in pandas mean?

enter image description here

enter image description here

axis=1 ,It will give the sum row wise,keepdims=True will maintain the 2D dimension. Hope it helps you.

Is there a way to make Firefox ignore invalid ssl-certificates?

The MitM Me addon will do this - but I think self-signed certificates is probably a better solution.

"The import org.springframework cannot be resolved."

This answer from here helped me:

You should take a look at the build path of your project to check whether the referenced libraries are still there. So right-click on your project, then "Properties -> Java Build Path -> Libraries" and check whether you still have the spring library JARs in the place that is mentioned there. If not, just re-add them to your classpath within this dialog.

http://forum.spring.io/forum/spring-projects/springsource-tool-suite/98653-springframework-cannot-be-resolved-error

Best way to determine user's locale within browser

This article suggests the following properties of the browser's navigator object:

  • navigator.language (Netscape - Browser Localization)
  • navigator.browserLanguage (IE-Specific - Browser Localized Language)
  • navigator.systemLanguage (IE-Specific - Windows OS - Localized Language)
  • navigator.userLanguage

Roll these into a javascript function and you should be able to guess the right language, in most circumstances. Be sure to degrade gracefully, so have a div containing your language choice links, so that if there is no javascript or the method doesn't work, the user can still decide. If it does work, just hide the div.

The only problem with doing this on the client side is that either you serve up all the languages to the client, or you have to wait until the script has run and detected the language before requesting the right version. Perhaps serving up the most popular language version as a default would irritate the fewest people.

Edit: I'd second Ivan's cookie suggestion, but make sure the user can always change the language later; not everyone prefers the language their browser defaults to.

String.replaceAll single backslashes with double backslashes

The String#replaceAll() interprets the argument as a regular expression. The \ is an escape character in both String and regex. You need to double-escape it for regex:

string.replaceAll("\\\\", "\\\\\\\\");

But you don't necessarily need regex for this, simply because you want an exact character-by-character replacement and you don't need patterns here. So String#replace() should suffice:

string.replace("\\", "\\\\");

Update: as per the comments, you appear to want to use the string in JavaScript context. You'd perhaps better use StringEscapeUtils#escapeEcmaScript() instead to cover more characters.

Extract text from a string

Using -replace

 $string = '% O0033(SUB RAD MSD 50R III) G91G1X-6.4Z-2.F500 G3I6.4Z-8.G3I6.4 G3R3.2X6.4F500 G91G0Z5. G91G1X-10.4 G3I10.4 G3R5.2X10.4 G90G0Z2. M99 %'
 $program = $string -replace '^%\sO\d{4}\((.+?)\).+$','$1'
 $program

SUB RAD MSD 50R III

what is the basic difference between stack and queue?

Imagine a stack of paper. The last piece put into the stack is on the top, so it is the first one to come out. This is LIFO. Adding a piece of paper is called "pushing", and removing a piece of paper is called "popping".

Imagine a queue at the store. The first person in line is the first person to get out of line. This is FIFO. A person getting into line is "enqueued", and a person getting out of line is "dequeued".

java build path problems

Go for the second option, Edit the project to agree with the latest JDK

  • Right click "JRE System Library [J2SE 1.5] in your project"
  • Choose "Properties"
  • Select "Workspace default JRE (jdk1.6)

enter image description here

Quick way to retrieve user information Active Directory

You can simplify this code to:

        DirectorySearcher searcher = new DirectorySearcher();
        searcher.Filter = "(&(objectCategory=user)(cn=steve.evans))";

        SearchResultCollection results = searcher.FindAll();

        if (results.Count == 1)
        {
            //do what you want to do
        }
        else if (results.Count == 0)
        {
            //user does not exist
        }
        else
        {
            //found more than one user
            //something is wrong
        }

If you can narrow down where the user is you can set searcher.SearchRoot to a specific OU that you know the user is under.

You should also use objectCategory instead of objectClass since objectCategory is indexed by default.

You should also consider searching on an attribute other than CN. For example it might make more sense to search on the username (sAMAccountName) since it's guaranteed to be unique.

Resize a large bitmap file to scaled output file on Android

Why not use the API?

int h = 48; // height in pixels
int w = 48; // width in pixels    
Bitmap scaled = Bitmap.createScaledBitmap(largeBitmap, w, h, true);

jQuery not working with IE 11

Place this meta tag after head tag

<meta http-equiv="x-ua-compatible" content="IE=edge">

Java check if boolean is null

The only thing that can be a null is a non-primivite.

A boolean which can only hold TRUE or FALSE is a primitive. The TRUE/FALSE in memory are actually numbers (0 and 1)

0 = FALSE

1 = TRUE

So when you instantiate an object it will be null String str; // will equal null

On the other hand if you instaniate a primitive it will be assigned to 0 default.

boolean isTrue; // will be 0

int i; // will be 0

When to use RabbitMQ over Kafka?

The short answer is "message acknowledgements". RabbitMQ can be configured to require message acknowledgements. If a receiver fails the message goes back on the queue and another receiver can try again. While you can accomplish this in Kafka with your own code, it works with RabbitMQ out of the box.

In my experience, if you have an application that has requirements to query a stream of information, Kafka and KSql are your best bet. If you want a queueing system you are better off with RabbitMQ.

Why use Redux over Facebook Flux?

Here is the simple explanation of Redux over Flux. Redux does not have a dispatcher.It relies on pure functions called reducers. It does not need a dispatcher. Each actions are handled by one or more reducers to update the single store. Since data is immutable, reducers returns a new updated state that updates the storeenter image description here

For more information Flux vs Redux

Getting Java version at runtime

Just a note that in Java 9 and above, the naming convention is different. System.getProperty("java.version") returns "9" rather than "1.9".

How to sort by dates excel?

It's actually really easy. Highlight the DATE column and make sure that its set as date in Excel. Highlight everything you want to change, Then go to [DATA]>[SORT]>[COLUMN] and set sorting by date. Hope it helps.

Select * from subquery

You can select every column from that sub-query by aliasing it and adding the alias before the *:

SELECT t.*, a+b AS total_sum
FROM
(
   SELECT SUM(column1) AS a, SUM(column2) AS b
   FROM table
) t

How to show MessageBox on asp.net?

MessageBox doesn't exist in ASP.NET. If you need functionality in the browser, like showing a message box, then you need to opt for javascript. ASP.NET provides you with means to inject javascript which gets rendered and executed when the html sent to the browser's loaded and displayed. You can use the following code in the Page_Load for example:

Type cstype = this.GetType();

// Get a ClientScriptManager reference from the Page class.
ClientScriptManager cs = Page.ClientScript;

// Check to see if the startup script is already registered.
if (!cs.IsStartupScriptRegistered(cstype, "PopupScript"))
{
    String cstext = "alert('Hello World');";
    cs.RegisterStartupScript(cstype, "PopupScript", cstext, true);
}

This sample's taken from MSDN.

Get url parameters from a string in .NET

if you want in get your QueryString on Default page .Default page means your current page url . you can try this code :

string paramIl = HttpUtility.ParseQueryString(this.ClientQueryString).Get("city");

How to add an image to an svg container using D3.js

 var svg = d3.select("body")
        .append("svg")
        .style("width", 200)
        .style("height", 100)

Error: Java: invalid target release: 11 - IntelliJ IDEA

If you are in Springboot please check the java version in the pom.xml file

<properties>
   <java.version>11</java.version>
</properties>

If this version doesn't match with your default version(Java) of the computer, that error can be happen.

Forcing label to flow inline with input that they label

Why don't You just use:

label {
    display: block;
    width: 50px;
    height: 24px;
    float: left;
}

Unable to execute dex: Multiple dex files define

ULTRA simple solution and finest:

Remove everything in Right Click Main Project's Folder -> Properties -> Java Build Path except Android X.Y (where X.Y is the version in android). Clean, and Build. Done!

Make sure before of that to have a single android-support-v4.jar.

Oracle SQL escape character (for a '&')

add this before your request

set define off;

Facebook Access Token for Pages

See here if you want to grant a Facebook App permanent access to a page (even when you / the app owner are logged out):

http://developers.facebook.com/docs/opengraph/using-app-tokens/

"An App Access Token does not expire unless you refresh the application secret through your app settings."

How to pass a null variable to a SQL Stored Procedure from C#.net code

Use DBNull.Value Better still, make your stored procedure parameters have defaults of NULL. Or use a Nullable<DateTime> parameter if the parameter will sometimes be a valid DateTime object

Why does .json() return a promise?

Also, what helped me understand this particular scenario that you described is the Promise API documentation, specifically where it explains how the promised returned by the then method will be resolved differently depending on what the handler fn returns:

if the handler function:

  • returns a value, the promise returned by then gets resolved with the returned value as its value;
  • throws an error, the promise returned by then gets rejected with the thrown error as its value;
  • returns an already resolved promise, the promise returned by then gets resolved with that promise's value as its value;
  • returns an already rejected promise, the promise returned by then gets rejected with that promise's value as its value.
  • returns another pending promise object, the resolution/rejection of the promise returned by then will be subsequent to the resolution/rejection of the promise returned by the handler. Also, the value of the promise returned by then will be the same as the value of the promise returned by the handler.

Python Pandas Counting the Occurrences of a Specific value

Couple of ways using count or sum

In [338]: df
Out[338]:
  col1 education
0    a       9th
1    b       9th
2    c       8th

In [335]: df.loc[df.education == '9th', 'education'].count()
Out[335]: 2

In [336]: (df.education == '9th').sum()
Out[336]: 2

In [337]: df.query('education == "9th"').education.count()
Out[337]: 2

How can I get my webapp's base URL in ASP.NET MVC?

So none of the ones listed here worked for me, but using a few of the answers, I got something working:

public string GetBaseUrl()
{
    var request = HttpContext.Current.Request;
    var appUrl = HttpRuntime.AppDomainAppVirtualPath;

    if (appUrl != "/") 
        appUrl = "/" + appUrl;

    var baseUrl = string.Format("{0}://{1}{2}", request.Url.Scheme, request.Url.Authority, appUrl);

    return baseUrl;
}

Update for ASP.NET Core / MVC 6:

ASP.NET Core makes this process a bit more painful, especially if you are deep in your code. You have 2 options to get at the HttpContext

1) Pass it in from your controller:

var model = new MyClass(HttpContext);

then in model:

private HttpContext currentContext;

public MyClass(HttpContext currentContext)
{
    this.currentContext = currentContext;
}

2) Perhaps the cleaner way is to inject it into your class, which starts with registering the types in your Startup:

public void ConfigureServices(IServiceCollection services)
{
    // Add framework services.
    services.AddMvc();

    services.AddTransient<MyClass, MyClass>();
    services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
}

then have it injected for you like this:

private HttpContext currentContext;

public MyClass(IHttpContextAccessor httpContextAccessor)
{
    currentContext = httpContextAccessor.HttpContext;
}

in either case, here is the updated for .NET Core GetBaseUrl():

public string GetBaseUrl()
{
    var request = currentContext.Request;

    var host = request.Host.ToUriComponent();

    var pathBase = request.PathBase.ToUriComponent();

    return $"{request.Scheme}://{host}{pathBase}";
}

SQLiteDatabase.query method

This is a more general answer meant to be a quick reference for future viewers.

Example

SQLiteDatabase db = helper.getReadableDatabase();

String table = "table2";
String[] columns = {"column1", "column3"};
String selection = "column3 =?";
String[] selectionArgs = {"apple"};
String groupBy = null;
String having = null;
String orderBy = "column3 DESC";
String limit = "10";

Cursor cursor = db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy, limit);

Explanation from the documentation

  • table String: The table name to compile the query against.
  • columns String: A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.
  • selection String: A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.
  • selectionArgs String: You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.
  • groupBy String: A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.
  • having String: A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.
  • orderBy String: How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.
  • limit String: Limits the number of rows returned by the query, formatted as LIMIT clause. Passing null denotes no LIMIT clause.

Better way to Format Currency Input editText?

CurrencyTextWatcher.java

public class CurrencyTextWatcher implements TextWatcher {

    private final static String DS = "."; //Decimal Separator
    private final static String TS = ","; //Thousands Separator
    private final static String NUMBERS = "0123456789"; //Numbers
    private final static int MAX_LENGTH = 13; //Maximum Length

    private String format;

    private DecimalFormat decimalFormat;
    private EditText editText;

    public CurrencyTextWatcher(EditText editText) {
        String pattern = "###" + TS + "###" + DS + "##";
        decimalFormat = new DecimalFormat(pattern);
        this.editText = editText;
        this.editText.setInputType(InputType.TYPE_CLASS_NUMBER);
        this.editText.setKeyListener(DigitsKeyListener.getInstance(NUMBERS + DS));
        this.editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(MAX_LENGTH)});
    }

    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void afterTextChanged(Editable editable) {

        editText.removeTextChangedListener(this);
        String value = editable.toString();
        if (!value.isEmpty()) {
            value = value.replace(TS, "");
            try {
                format = decimalFormat.format(Double.parseDouble(value));
                format = format.replace("0", "");
            } catch (Exception e) {
                System.out.println(e.getMessage());
            }

            editText.setText(format);
        }

        editText.addTextChangedListener(this);
    }
}

EditTextCurrency.java

public class EditTextCurrency extends AppCompatEditText {
    public EditTextCurrency(Context context) {
        super(context);
    }

    public EditTextCurrency(Context context, AttributeSet attrs) {
        super(context, attrs);
        addTextChangedListener(new CurrencyTextWatcher(this));
    }
}

enter image description here

Add (insert) a column between two columns in a data.frame

df <- data.frame(a=c(1,2), b=c(3,4), c=c(5,6))
df %>%
  mutate(d= a/2) %>%
  select(a, b, d, c)

results

  a b   d c
1 1 3 0.5 5
2 2 4 1.0 6

I suggest to use dplyr::select after dplyr::mutate. It has many helpers to select/de-select subset of columns.

In the context of this question the order by which you select will be reflected in the output data.frame.

how to convert a string to a bool

I know this doesn't answer your question, but just to help other people. If you are trying to convert "true" or "false" strings to boolean:

Try Boolean.Parse

bool val = Boolean.Parse("true"); ==> true
bool val = Boolean.Parse("True"); ==> true
bool val = Boolean.Parse("TRUE"); ==> true
bool val = Boolean.Parse("False"); ==> false
bool val = Boolean.Parse("1"); ==> Exception!
bool val = Boolean.Parse("diffstring"); ==> Exception!

MySQL, Check if a column exists in a table with SQL

I am using this simple script:

mysql_query("select $column from $table") or mysql_query("alter table $table add $column varchar (20)");

It works if you are already connected to the database.

COALESCE Function in TSQL

declare @store table (store_id varchar(300))
insert into @store 
values ('aa'),('bb'),('cc')
declare @str varchar (4000)
select @str = concat(@str+',',store_id) from @store
select @str

Create a one to many relationship using SQL Server

  1. Define two tables (example A and B), with their own primary key
  2. Define a column in Table A as having a Foreign key relationship based on the primary key of Table B

This means that Table A can have one or more records relating to a single record in Table B.

If you already have the tables in place, use the ALTER TABLE statement to create the foreign key constraint:

ALTER TABLE A ADD CONSTRAINT fk_b FOREIGN KEY (b_id) references b(id) 
  • fk_b: Name of the foreign key constraint, must be unique to the database
  • b_id: Name of column in Table A you are creating the foreign key relationship on
  • b: Name of table, in this case b
  • id: Name of column in Table B

Setting Curl's Timeout in PHP

Your code sets the timeout to 1000 seconds. For milliseconds, use CURLOPT_TIMEOUT_MS.

Check if an array item is set in JS

TLDR; The best I can come up with is this: (Depending on your use case, there are a number of ways to optimize this function.)

function arrayIndexExists(array, index){
    if ( typeof index !== 'number' && index === parseInt(index).toString()) {
        index = parseInt(index);
    } else {
        return false;//to avoid checking typeof again
    }
    return typeof index === 'number' && index % 1===0 && index >= 0 && array.hasOwnKey(index);
}

The other answer's examples get close and will work for some (probably most) purposes, but are technically quite incorrect for reasons I explain below.

Javascript arrays only use 'numerical' keys. When you set an "associative key" on an array, you are actually setting a property on that array object, not an element of that array. For example, this means that the "associative key" will not be iterated over when using Array.forEach() and will not be included when calculating Array.length. (The exception for this is strings like '0' will resolve to an element of the array, but strings like ' 0' won't.)

Additionally, checking array element or object property that doesn't exist does evaluate as undefined, but that doesn't actually tell you that the array element or object property hasn't been set yet. For example, undefined is also the result you get by calling a function that doesn't terminate with a return statement. This could lead to some strange errors and difficulty debugging code.

This can be confusing, but can be explored very easily using your browser's javascript console. (I used chrome, each comment indicates the evaluated value of the line before it.);

var foo = new Array();
foo;
//[]
foo.length;
//0
foo['bar'] = 'bar';
//"bar"
foo;
//[]
foo.length;
//0
foo.bar;
//"bar"

This shows that associative keys are not used to access elements in the array, but for properties of the object.

foo[0] = 0;
//0
foo;
//[0]
foo.length;
//1
foo[2] = undefined
//undefined
typeof foo[2]
//"undefined"
foo.length
//3

This shows that checking typeof doesn't allow you to see if an element has been set.

var foo = new Array();
//undefined
foo;
//[]
foo[0] = 0;
//0
foo['0']
//0
foo[' 0']
//undefined

This shows the exception I mentioned above and why you can't just use parseInt();

If you want to use associative arrays, you are better off using simple objects as other answers have recommended.

Jquery/Ajax call with timer

If you want to set something on a timer, you can use JavaScript's setTimeout or setInterval methods:

setTimeout ( expression, timeout );
setInterval ( expression, interval );

Where expression is a function and timeout and interval are integers in milliseconds. setTimeout runs the timer once and runs the expression once whereas setInterval will run the expression every time the interval passes.

So in your case it would work something like this:

setInterval(function() {
    //call $.ajax here
}, 5000); //5 seconds

As far as the Ajax goes, see jQuery's ajax() method. If you run an interval, there is nothing stopping you from calling the same ajax() from other places in your code.


If what you want is for an interval to run every 30 seconds until a user initiates a form submission...and then create a new interval after that, that is also possible:

setInterval() returns an integer which is the ID of the interval.

var id = setInterval(function() {
    //call $.ajax here
}, 30000); // 30 seconds

If you store that ID in a variable, you can then call clearInterval(id) which will stop the progression.

Then you can reinstantiate the setInterval() call after you've completed your ajax form submission.

Getting hold of the outer class object from the inner class object

if you don't have control to modify the inner class, the refection may help you (but not recommend). this$0 is reference in Inner class which tells which instance of Outer class was used to create current instance of Inner class.

How do I lowercase a string in C?

to convert to lower case is equivalent to rise bit 0x60 if you restrict yourself to ASCII:

for(char *p = pstr; *p; ++p)
    *p = *p > 0x40 && *p < 0x5b ? *p | 0x60 : *p;

Button text toggle in jquery

You could also use .toggle() like so:

$(".pushme").toggle(function() {
    $(this).text("DON'T PUSH ME");
}, function() {
    $(this).text("PUSH ME");
});

More info at http://api.jquery.com/toggle-event/.

This way also makes it pretty easy to change the text or add more than just 2 differing states.

How to wait for the 'end' of 'resize' event and only then perform an action?

I wrote a function that passes a function when wrapped in any resize event. It uses an interval so that the resize even isn't constantly creating timeout events. This allows it to perform independently of the resize event other than a log entry that should be removed in production.

https://github.com/UniWrighte/resizeOnEnd/blob/master/resizeOnEnd.js

        $(window).resize(function(){
            //call to resizeEnd function to execute function on resize end.
    //can be passed as function name or anonymous function
            resizeEnd(function(){



    });

        });

        //global variables for reference outside of interval
        var interval = null;
        var width = $(window).width();
    var numi = 0; //can be removed in production
        function resizeEnd(functionCall){
            //check for null interval
            if(!interval){
                //set to new interval
                interval = setInterval(function(){
        //get width to compare
                    width2 = $(window).width();
        //if stored width equals new width
                    if(width === width2){
                        //clear interval, set to null, and call passed function
                        clearInterval(interval);
                        interval = null; //precaution
                        functionCall();

                    }
        //set width to compare on next interval after half a second
                    width = $(window).width();
                }, 500);

            }else{
                //logging that should be removed in production
                console.log("function call " + numi++ + " and inteval set skipped");

            }

}

How to display my location on Google Maps for Android API v2

Java code:

public class MapActivity extends FragmentActivity implements LocationListener  {

    GoogleMap googleMap;
    LatLng myPosition;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_map);

        // Getting reference to the SupportMapFragment of activity_main.xml
        SupportMapFragment fm = (SupportMapFragment)
        getSupportFragmentManager().findFragmentById(R.id.map);

        // Getting GoogleMap object from the fragment
        googleMap = fm.getMap();

        // Enabling MyLocation Layer of Google Map
        googleMap.setMyLocationEnabled(true);

        // Getting LocationManager object from System Service LOCATION_SERVICE
        LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        // Creating a criteria object to retrieve provider
        Criteria criteria = new Criteria();

        // Getting the name of the best provider
        String provider = locationManager.getBestProvider(criteria, true);

        // Getting Current Location
        Location location = locationManager.getLastKnownLocation(provider);

        if (location != null) {
            // Getting latitude of the current location
            double latitude = location.getLatitude();

            // Getting longitude of the current location
            double longitude = location.getLongitude();

            // Creating a LatLng object for the current location
            LatLng latLng = new LatLng(latitude, longitude);

            myPosition = new LatLng(latitude, longitude);

            googleMap.addMarker(new MarkerOptions().position(myPosition).title("Start"));
        }
    }
}

activity_map.xml:

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:map="http://schemas.android.com/apk/res-auto"
  android:id="@+id/map"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  class="com.google.android.gms.maps.SupportMapFragment"/>

You will get your current location in a blue circle.

Using subprocess to run Python script on Windows

Just found sys.executable - the full path to the current Python executable, which can be used to run the script (instead of relying on the shbang, which obviously doesn't work on Windows)

import sys
import subprocess

theproc = subprocess.Popen([sys.executable, "myscript.py"])
theproc.communicate()

How to get current working directory using vba?

Use Application.ActiveWorkbook.Path for just the path itself (without the workbook name) or Application.ActiveWorkbook.FullName for the path with the workbook name.

How to make ng-repeat filter out duplicate results

UPDATE

I was recomending the use of Set but sorry this doesn't work for ng-repeat, nor Map since ng-repeat only works with array. So ignore this answer. anyways if you need to filter out duplicates one way is as other has said using angular filters, here is the link for it to the getting started section.


Old answer

Yo can use the ECMAScript 2015 (ES6) standard Set Data structure, instead of an Array Data Structure this way you filter repeated values when adding to the Set. (Remember sets don't allow repeated values). Really easy to use:

var mySet = new Set();

mySet.add(1);
mySet.add(5);
mySet.add("some text");
var o = {a: 1, b: 2};
mySet.add(o);

mySet.has(1); // true
mySet.has(3); // false, 3 has not been added to the set
mySet.has(5);              // true
mySet.has(Math.sqrt(25));  // true
mySet.has("Some Text".toLowerCase()); // true
mySet.has(o); // true

mySet.size; // 4

mySet.delete(5); // removes 5 from the set
mySet.has(5);    // false, 5 has been removed

mySet.size; // 3, we just removed one value

Copying text to the clipboard using Java

For JavaFx based applications.

        //returns System Clipboard
        final Clipboard clipboard = Clipboard.getSystemClipboard();
        // ClipboardContent provides flexibility to store data in different formats
        final ClipboardContent content = new ClipboardContent();
        content.putString("Some text");
        content.putHtml("<b>Some</b> text");
        //this will be replaced by previous putString
        content.putString("Some different text");
        //set the content to clipboard
        clipboard.setContent(content);
       // validate before retrieving it
        if(clipboard.hasContent(DataFormat.HTML)){
            System.out.println(clipboard.getHtml());
        }
        if(clipboard.hasString()){
            System.out.println(clipboard.getString());
        }

ClipboardContent can save multiple data in several data formats like(html,url,plain text,image).

For more information see official documentation

Uncaught TypeError: .indexOf is not a function

Convert timeofday to string to use indexOf

var timeofday = new Date().getHours() + (new Date().getMinutes()) / 60;
console.log(typeof(timeofday)) // for testing will log number
function timeD2C(time) { // Converts 11.5 (decimal) to 11:30 (colon)
    var pos = time.indexOf('.');
    var hrs = time.substr(1, pos - 1);
    var min = (time.substr(pos, 2)) * 60;

    if (hrs > 11) {
        hrs = (hrs - 12) + ":" + min + " PM";
    } else {
        hrs += ":" + min + " AM";
    }
    return hrs;
}
 // "" for typecasting to string
 document.getElementById("oset").innerHTML = timeD2C(""+timeofday);

Test Here

Solution 2

use toString() to convert to string

document.getElementById("oset").innerHTML = timeD2C(timeofday.toString());

jsfiddle with toString()

LoDash: Get an array of values from an array of object properties

Since version v4.x you should use _.map:

_.map(users, 'id'); // [12, 14, 16, 18]

this way it is corresponds to native Array.prototype.map method where you would write (ES2015 syntax):

users.map(user => user.id); // [12, 14, 16, 18]

Before v4.x you could use _.pluck the same way:

_.pluck(users, 'id'); // [12, 14, 16, 18]

Connect Java to a MySQL database

String url = "jdbc:mysql://127.0.0.1:3306/yourdatabase";
String user = "username";
String password = "password";

// Load the Connector/J driver
Class.forName("com.mysql.jdbc.Driver").newInstance();
// Establish connection to MySQL
Connection conn = DriverManager.getConnection(url, user, password);

Mod of negative number is melting my brain

ShreevatsaR's answer won't work for all cases, even if you add "if(m<0) m=-m;", if you account for negative dividends/divisors.

For example, -12 mod -10 will be 8, and it should be -2.

The following implementation will work for both positive and negative dividends / divisors and complies with other implementations (namely, Java, Python, Ruby, Scala, Scheme, Javascript and Google's Calculator):

internal static class IntExtensions
{
    internal static int Mod(this int a, int n)
    {
        if (n == 0)
            throw new ArgumentOutOfRangeException("n", "(a mod 0) is undefined.");

        //puts a in the [-n+1, n-1] range using the remainder operator
        int remainder = a%n;

        //if the remainder is less than zero, add n to put it in the [0, n-1] range if n is positive
        //if the remainder is greater than zero, add n to put it in the [n-1, 0] range if n is negative
        if ((n > 0 && remainder < 0) ||
            (n < 0 && remainder > 0))
            return remainder + n;
        return remainder;
    }
}

Test suite using xUnit:

    [Theory]
    [PropertyData("GetTestData")]
    public void Mod_ReturnsCorrectModulo(int dividend, int divisor, int expectedMod)
    {
        Assert.Equal(expectedMod, dividend.Mod(divisor));
    }

    [Fact]
    public void Mod_ThrowsException_IfDivisorIsZero()
    {
        Assert.Throws<ArgumentOutOfRangeException>(() => 1.Mod(0));
    }

    public static IEnumerable<object[]> GetTestData
    {
        get
        {
            yield return new object[] {1, 1, 0};
            yield return new object[] {0, 1, 0};
            yield return new object[] {2, 10, 2};
            yield return new object[] {12, 10, 2};
            yield return new object[] {22, 10, 2};
            yield return new object[] {-2, 10, 8};
            yield return new object[] {-12, 10, 8};
            yield return new object[] {-22, 10, 8};
            yield return new object[] { 2, -10, -8 };
            yield return new object[] { 12, -10, -8 };
            yield return new object[] { 22, -10, -8 };
            yield return new object[] { -2, -10, -2 };
            yield return new object[] { -12, -10, -2 };
            yield return new object[] { -22, -10, -2 };
        }
    }

How do I POST XML data to a webservice with Postman?

Send XML requests with the raw data type, then set the Content-Type to text/xml.


  1. After creating a request, use the dropdown to change the request type to POST.

    Set request type to POST

  2. Open the Body tab and check the data type for raw.

    Setting data type to raw

  3. Open the Content-Type selection box that appears to the right and select either XML (application/xml) or XML (text/xml)

    Selecting content-type text/xml

  4. Enter your raw XML data into the input field below

    Example of XML request in Postman

  5. Click Send to submit your XML Request to the specified server.

    Clicking the Send button

twitter bootstrap typeahead ajax example

I've augmented the original typeahead Bootstrap plugin with ajax capabilities. Very easy to use:

$("#ajax-typeahead").typeahead({
     ajax: "/path/to/source"
});

Here's the github repo: Ajax-Typeahead

Create table using Javascript

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
        <title>Insert title here</title>
    </head>
    <body>
        <table id="myTable" cellpadding="2" cellspacing="2" border="1" onclick="tester()"></table>
        <script>
            var student;
            for (var j = 0; j < 10; j++) {
                student = {
                    name: "Name" + j,
                    rank: "Rank" + j,
                    stuclass: "Class" + j,
                };
                var table = document.getElementById("myTable");
                var row = table.insertRow(j);
                var cell1 = row.insertCell(0);
                var cell2 = row.insertCell(1);
                var cell3 = row.insertCell(2);

                cell1.innerHTML = student.name,
                cell2.innerHTML = student.rank,
                cell3.innerHTML = student.stuclass;
            }
        </script>
    </body>
</html>

Bootstrap dropdown menu not working (not dropping down when clicked)

i faced the same problem , the solution worked for me , hope it will work for you too.

<script src="content/js/jquery.min.js"></script>
<script src="content/js/bootstrap.min.js"></script>
<script>
    $(document).ready(function () {
        $('.dropdown-toggle').dropdown();
    });
</script>

Please include the "jquery.min.js" file before "bootstrap.min.js" file, if you shuffle the order it will not work.

Loop Through All Subfolders Using VBA

And to complement Rich's recursive answer, a non-recursive method.

Public Sub NonRecursiveMethod()
    Dim fso, oFolder, oSubfolder, oFile, queue As Collection

    Set fso = CreateObject("Scripting.FileSystemObject")
    Set queue = New Collection
    queue.Add fso.GetFolder("your folder path variable") 'obviously replace

    Do While queue.Count > 0
        Set oFolder = queue(1)
        queue.Remove 1 'dequeue
        '...insert any folder processing code here...
        For Each oSubfolder In oFolder.SubFolders
            queue.Add oSubfolder 'enqueue
        Next oSubfolder
        For Each oFile In oFolder.Files
            '...insert any file processing code here...
        Next oFile
    Loop

End Sub

You can use a queue for FIFO behaviour (shown above), or you can use a stack for LIFO behaviour which would process in the same order as a recursive approach (replace Set oFolder = queue(1) with Set oFolder = queue(queue.Count) and replace queue.Remove(1) with queue.Remove(queue.Count), and probably rename the variable...)

How can I use grep to find a word inside a folder?

The answer you selected is fine, and it works, but it isn't the correct way to do it, because:

grep -nr yourString* .

This actually searches the string "yourStrin" and "g" 0 or many times.

So the proper way to do it is:

grep -nr \w*yourString\w* .

This command searches the string with any character before and after on the current folder.

Passing an Object from an Activity to a Fragment

To pass an object to a fragment, do the following:

First store the objects in Bundle, don't forget to put implements serializable in class.

            CategoryRowFragment fragment = new CategoryRowFragment();

            // pass arguments to fragment
            Bundle bundle = new Bundle();

            // event list we want to populate
            bundle.putSerializable("eventsList", eventsList);

            // the description of the row
            bundle.putSerializable("categoryRow", categoryRow);

            fragment.setArguments(bundle);

Then retrieve bundles in Fragment

_x000D_
_x000D_
       // events that will be populated in this row_x000D_
        mEventsList = (ArrayList<Event>)getArguments().getSerializable("eventsList");_x000D_
_x000D_
        // description of events to be populated in this row_x000D_
        mCategoryRow = (CategoryRow)getArguments().getSerializable("categoryRow");
_x000D_
_x000D_
_x000D_

Link entire table row?

I feel like the simplest solution is sans javascript and simply putting the link in each cell (provided you don't have massive gullies between your cells or really think border lines). Have your css:

.tableClass td a{
   display: block;
}

and then add a link per cell:

<table class="tableClass">
    <tr>
        <td><a href="#link">Link name</a></td>
        <td><a href="#link">Link description</a></td>
        <td><a href="#link">Link somthing else</a></td>
    </tr>
</table>

boring but clean.

Unable to load DLL (Module could not be found HRESULT: 0x8007007E)

Make sure you set the Build Platform Target to x86 or x64 so that it is compatible with your DLL - which might be compiled for a 32 bit platform.

Easiest way to mask characters in HTML(5) text input

A little late, but a useful plugin that will actually use a mask to give a bit more restriction on user input.

<div class="col-sm-3 col-md-6 col-lg-4">
  <div class="form-group">
     <label for="addPhone">Phone Number *</label>
      <input id="addPhone" name="addPhone" type="text" class="form-control 
       required" data-mask="(999) 999-9999"placeholder>
    <span class="help-block">(999) 999-9999</span>
  </div>
</div>

 <!-- Input Mask -->
 <script src="js/plugins/jasny/jasny-bootstrap.min.js"></script>

enter image description here

More info on the plugin https://www.jasny.net/bootstrap/2.3.1/javascript.html#inputmask

When to use 'raise NotImplementedError'?

One could also do a raise NotImplementedError() inside the child method of an @abstractmethod-decorated base class method.


Imagine writing a control script for a family of measurement modules (physical devices). The functionality of each module is narrowly-defined, implementing just one dedicated function: one could be an array of relays, another a multi-channel DAC or ADC, another an ammeter etc.

Much of the low-level commands in use would be shared between the modules for example to read their ID numbers or to send a command to them. Let's see what we have at this point:

Base Class

from abc import ABC, abstractmethod  #< we'll make use of these later

class Generic(ABC):
    ''' Base class for all measurement modules. '''

    # Shared functions
    def __init__(self):
        # do what you must...

    def _read_ID(self):
        # same for all the modules

    def _send_command(self, value):
        # same for all the modules

Shared Verbs

We then realise that much of the module-specific command verbs and, therefore, the logic of their interfaces is also shared. Here are 3 different verbs whose meaning would be self-explanatory considering a number of target modules.

  • get(channel)

  • relay: get the on/off status of the relay on channel

  • DAC: get the output voltage on channel

  • ADC: get the input voltage on channel

  • enable(channel)

  • relay: enable the use of the relay on channel

  • DAC: enable the use of the output channel on channel

  • ADC: enable the use of the input channel on channel

  • set(channel)

  • relay: set the relay on channel on/off

  • DAC: set the output voltage on channel

  • ADC: hmm... nothing logical comes to mind.


Shared Verbs Become Enforced Verbs

I'd argue that there is a strong case for the above verbs to be shared across the modules as we saw that their meaning is evident for each one of them. I'd continue writing my base class Generic like so:

class Generic(ABC):  # ...continued
    
    @abstractmethod
    def get(self, channel):
        pass

    @abstractmethod
    def enable(self, channel):
        pass

    @abstractmethod
    def set(self, channel):
        pass

Subclasses

We now know that our subclasses will all have to define these methods. Let's see what it could look like for the ADC module:

class ADC(Generic):

    def __init__(self):
        super().__init__()  #< applies to all modules
        # more init code specific to the ADC module
    
    def get(self, channel):
        # returns the input voltage measured on the given 'channel'

    def enable(self, channel):
        # enables accessing the given 'channel'

You may now be wondering:

But this won't work for the ADC module as set makes no sense there as we've just seen this above!

You're right: not implementing set is not an option as Python would then fire the error below when you tried to instantiate your ADC object.

TypeError: Can't instantiate abstract class 'ADC' with abstract methods 'set'

So you must implement something, because we made set an enforced verb (aka '@abstractmethod'), which is shared by two other modules but, at the same time, you must also not implement anything as set does not make sense for this particular module.

NotImplementedError to the Rescue

By completing the ADC class like this:

class ADC(Generic): # ...continued

    def set(self, channel):
        raise NotImplementedError("Can't use 'set' on an ADC!")

You are doing three very good things at once:

  1. You are protecting a user from erroneously issuing a command ('set') that is not (and shouldn't!) be implemented for this module.
  2. You are telling them explicitly what the problem is (see TemporalWolf's link about 'Bare exceptions' for why this is important)
  3. You are protecting the implementation of all the other modules for which the enforced verbs do make sense. I.e. you ensure that those modules for which these verbs do make sense will implement these methods and that they will do so using exactly these verbs and not some other ad-hoc names.

Simple java program of pyramid

public static void showPyramid(int level)
{
    for(int i=0;i<level;i++)
    {
        for(int j=0;j<level-i-1;j++)
        {
            System.out.print(" ");
        }
        for(int k=level-i;k<=level;k++)
        {
            System.out.print("*");
        }
        for(int k=level-i;k<level;k++)
        {
            System.out.print("*");
        }
        for(int j=0;j<level-i;j++)
        {
            System.out.print(" ");
        }

        System.out.print("\n");
    }

}

Output

     *          
    ***         
   *****        
  *******       
 *********      
***********     




Regex pattern to match at least 1 number and 1 character in a string

Why not first apply the whole test, and then add individual tests for characters and numbers? Anyway, if you want to do it all in one regexp, use positive lookahead:

/^(?=.*[0-9])(?=.*[a-zA-Z])([a-zA-Z0-9]+)$/

How to return data from PHP to a jQuery ajax call

It's an argument passed to your success function:

$.ajax({
  type: "POST",
  url: "somescript.php",
  datatype: "html",
  data: dataString,
  success: function(data) {
    alert(data);
    }
});

The full signature is success(data, textStatus, XMLHttpRequest), but you can use just he first argument if it's a simple string coming back. As always, see the docs for a full explanation :)

Force an SVN checkout command to overwrite current files

Try the --force option. svn help checkout gives the details.

How to populate HTML dropdown list with values from database

Use OOP concept instead. Create a class with function

class MyClass {

...

function getData($query) {
    $result = mysqli_query($this->conn, $query);
    while($row=mysqli_fetch_assoc($result)) {
        $resultset[] = $row;
    }       
    if(!empty($resultset))
        return $resultset;
} }

and then use the class object to call function in your code

<?php 

    $obj = new MyClass();
    $row = $obj->getData("select city_name from city"); 
?>
<select>
    <?php foreach($row as $row){ ?>
        <option><?php echo $row['city_name'] ?></option>

<?php  } ?>
</select>

Full code and description can be found here

Remove Array Value By index in jquery

Use the splice method.

ArrayName.splice(indexValueOfArray,1);

This removes 1 item from the array starting at indexValueOfArray.

Error while sending QUERY packet

You may also have this error if the variable wait_timeout is too low.

If so, you may set it higher like that:

SET GLOBAL wait_timeout=10;

This was the solution for the same error in my case.

Python: list of lists

First, I strongly recommend that you rename your variable list to something else. list is the name of the built-in list constructor, and you're hiding its normal function. I will rename list to a in the following.

Python names are references that are bound to objects. That means that unless you create more than one list, whenever you use a it's referring to the same actual list object as last time. So when you call

listoflists.append((a, a[0]))

you can later change a and it changes what the first element of that tuple points to. This does not happen with a[0] because the object (which is an integer) pointed to by a[0] doesn't change (although a[0] points to different objects over the run of your code).

You can create a copy of the whole list a using the list constructor:

listoflists.append((list(a), a[0]))

Or, you can use the slice notation to make a copy:

listoflists.append((a[:], a[0]))

Windows equivalent of the 'tail' command

I don't think there is way out of the box. There is no such command in DOS and batch files are far to limited to simulate it (without major pain).

Convert columns to string in Pandas

pandas >= 1.0: It's time to stop using astype(str)!

Prior to pandas 1.0 (well, 0.25 actually) this was the defacto way of declaring a Series/column as as string:

# pandas <= 0.25
# Note to pedants: specifying the type is unnecessary since pandas will 
# automagically infer the type as object
s = pd.Series(['a', 'b', 'c'], dtype=str)
s.dtype
# dtype('O')

From pandas 1.0 onwards, consider using "string" type instead.

# pandas >= 1.0
s = pd.Series(['a', 'b', 'c'], dtype="string")
s.dtype
# StringDtype

Here's why, as quoted by the docs:

  1. You can accidentally store a mixture of strings and non-strings in an object dtype array. It’s better to have a dedicated dtype.

  2. object dtype breaks dtype-specific operations like DataFrame.select_dtypes(). There isn’t a clear way to select just text while excluding non-text but still object-dtype columns.

  3. When reading code, the contents of an object dtype array is less clear than 'string'.

See also the section on Behavioral Differences between "string" and object.

Extension types (introduced in 0.24 and formalized in 1.0) are closer to pandas than numpy, which is good because numpy types are not powerful enough. For example NumPy does not have any way of representing missing data in integer data (since type(NaN) == float). But pandas can using Nullable Integer columns.


Why should I stop using it?

Accidentally mixing dtypes
The first reason, as outlined in the docs is that you can accidentally store non-text data in object columns.

# pandas <= 0.25
pd.Series(['a', 'b', 1.23])   # whoops, this should have been "1.23"

0       a
1       b
2    1.23
dtype: object

pd.Series(['a', 'b', 1.23]).tolist()
# ['a', 'b', 1.23]   # oops, pandas was storing this as float all the time.
# pandas >= 1.0
pd.Series(['a', 'b', 1.23], dtype="string")

0       a
1       b
2    1.23
dtype: string

pd.Series(['a', 'b', 1.23], dtype="string").tolist()
# ['a', 'b', '1.23']   # it's a string and we just averted some potentially nasty bugs.

Challenging to differentiate strings and other python objects
Another obvious example example is that it's harder to distinguish between "strings" and "objects". Objects are essentially the blanket type for any type that does not support vectorizable operations.

Consider,

# Setup
df = pd.DataFrame({'A': ['a', 'b', 'c'], 'B': [{}, [1, 2, 3], 123]})
df
 
   A          B
0  a         {}
1  b  [1, 2, 3]
2  c        123

Upto pandas 0.25, there was virtually no way to distinguish that "A" and "B" do not have the same type of data.

# pandas <= 0.25  
df.dtypes

A    object
B    object
dtype: object

df.select_dtypes(object)

   A          B
0  a         {}
1  b  [1, 2, 3]
2  c        123

From pandas 1.0, this becomes a lot simpler:

# pandas >= 1.0
# Convenience function I call to help illustrate my point.
df = df.convert_dtypes()
df.dtypes

A    string
B    object
dtype: object

df.select_dtypes("string")

   A
0  a
1  b
2  c

Readability
This is self-explanatory ;-)


OK, so should I stop using it right now?

...No. As of writing this answer (version 1.1), there are no performance benefits but the docs expect future enhancements to significantly improve performance and reduce memory usage for "string" columns as opposed to objects. With that said, however, it's never too early to form good habits!

What exactly is "exit" in PowerShell?

It's a reserved keyword (like return, filter, function, break).

Reference

Also, as per Section 7.6.4 of Bruce Payette's Powershell in Action:

But what happens when you want a script to exit from within a function defined in that script? ... To make this easier, Powershell has the exit keyword.

Of course, as other have pointed out, it's not hard to do what you want by wrapping exit in a function:

PS C:\> function ex{exit}
PS C:\> new-alias ^D ex

disable horizontal scroll on mobile web

try like this

css

*{
    box-sizing: border-box;
    -webkit-box-sizing: border-box;
    -msbox-sizing: border-box;
}
body{
   overflow-x: hidden;
}
img{
   max-width:100%;
}

ScriptManager.RegisterStartupScript code not working - why?

Try this code...

ScriptManager.RegisterClientScriptBlock(UpdatePanel1, this.GetType(), "script", "alert('Hi');", true);

Where UpdatePanel1 is the id for Updatepanel on your page

How do I generate a constructor from class fields using Visual Studio (and/or ReSharper)?

I'm using the following trick:

I select the declaration of the class with the data-members and press:

Ctrl+C, Shift+Ctrl+C, Ctrl+V.

  • The first command copies the declaration to the clipboard,
  • The second command is a shortcut that invokes the PROGRAM
  • The last command overwrites the selection by text from the clipboard.

The PROGRAM gets the declaration from the clipboard, finds the name of the class, finds all members and their types, generates constructor and copies it all back into the clipboard.

We are doing it with freshmen on my "Programming-I" practice (Charles University, Prague) and most of students gets it done till the end of the hour.

If you want to see the source code, let me know.

How to remove gaps between subplots in matplotlib?

With recent matplotlib versions you might want to try Constrained Layout. This does not work with plt.subplot() however, so you need to use plt.subplots() instead:

fig, axs = plt.subplots(4, 4, constrained_layout=True)

ip address validation in python using regex

Why not use a library function to validate the ip address?

>>> ip="241.1.1.112343434" 
>>> socket.inet_aton(ip)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
socket.error: illegal IP address string passed to inet_aton

Conversion failed when converting from a character string to uniqueidentifier

this fails:

 DECLARE @vPortalUID NVARCHAR(32)
 SET @vPortalUID='2A66057D-F4E5-4E2B-B2F1-38C51A96D385'
 DECLARE @nPortalUID AS UNIQUEIDENTIFIER
 SET @nPortalUID = CAST(@vPortalUID AS uniqueidentifier)
 PRINT @nPortalUID

this works

 DECLARE @vPortalUID NVARCHAR(36)
 SET @vPortalUID='2A66057D-F4E5-4E2B-B2F1-38C51A96D385'
 DECLARE @nPortalUID AS UNIQUEIDENTIFIER
 SET @nPortalUID = CAST(@vPortalUID AS UNIQUEIDENTIFIER)
 PRINT @nPortalUID

the difference is NVARCHAR(36), your input parameter is too small!

Taskkill /f doesn't kill a process

I've seen this a few times and my only solution was a re-boot.

You could try using PowerShell: Get-Process devenv | kill

But if the other methods failed, this probably will too. :-(

A TypeScript GUID class?

There is an implementation in my TypeScript utilities based on JavaScript GUID generators.

Here is the code:

_x000D_
_x000D_
class Guid {_x000D_
  static newGuid() {_x000D_
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {_x000D_
      var r = Math.random() * 16 | 0,_x000D_
        v = c == 'x' ? r : (r & 0x3 | 0x8);_x000D_
      return v.toString(16);_x000D_
    });_x000D_
  }_x000D_
}_x000D_
_x000D_
// Example of a bunch of GUIDs_x000D_
for (var i = 0; i < 100; i++) {_x000D_
  var id = Guid.newGuid();_x000D_
  console.log(id);_x000D_
}
_x000D_
_x000D_
_x000D_

Please note the following:

C# GUIDs are guaranteed to be unique. This solution is very likely to be unique. There is a huge gap between "very likely" and "guaranteed" and you don't want to fall through this gap.

JavaScript-generated GUIDs are great to use as a temporary key that you use while waiting for a server to respond, but I wouldn't necessarily trust them as the primary key in a database. If you are going to rely on a JavaScript-generated GUID, I would be tempted to check a register each time a GUID is created to ensure you haven't got a duplicate (an issue that has come up in the Chrome browser in some cases).

Best way to combine two or more byte arrays in C#

All you need to pass list of Byte Arrays and this function will return you the Array of Bytes (Merged). This is the best solution i think :).

public static byte[] CombineMultipleByteArrays(List<byte[]> lstByteArray)
        {
            using (var ms = new MemoryStream())
            {
                using (var doc = new iTextSharp.text.Document())
                {
                    using (var copy = new PdfSmartCopy(doc, ms))
                    {
                        doc.Open();
                        foreach (var p in lstByteArray)
                        {
                            using (var reader = new PdfReader(p))
                            {
                                copy.AddDocument(reader);
                            }
                        }

                        doc.Close();
                    }
                }
                return ms.ToArray();
            }
        }

Delete all data rows from an Excel table (apart from the first)

I wanted to keep the formulas in place, which the above code did not do.

Here's what I've been doing, note that this leaves one empty row in the table.

Sub DeleteTableRows(ByRef Table As ListObject, KeepFormulas as boolean)

On Error Resume Next

if not KeepFormulas then
    Table.DataBodyRange.clearcontents
end if

Table.DataBodyRange.Rows.Delete

On Error GoTo 0

End Sub

(PS don't ask me why!)

Setting timezone to UTC (0) in PHP

You can always check this maintained list to timezones

https://www.php.net/manual/en/function.date.php

How to get a list column names and datatypes of a table in PostgreSQL?

SELECT column_name,data_type 
FROM information_schema.columns 
WHERE
table_name = 'your_table_name' 
AND table_catalog = 'your_database_name' 
AND table_schema = 'your_schema_name';

php implode (101) with quotes

$array = array('lastname', 'email', 'phone');


echo "'" . implode("','", $array) . "'";

Good ways to manage a changelog using git?

This was about 3-4 years ago, but for the sake of future searchers, it's now possible to generate gorgeous logs with:

git log --oneline --decorate

Or, if you want it even prettier (with color for terminal):

git log --oneline --decorate --color

Piping that output to ChangeLog is what I currently use in all my projects, it's simply amazing.

String to Binary in C#

Here you go:

public static byte[] ConvertToByteArray(string str, Encoding encoding)
{
    return encoding.GetBytes(str);
}

public static String ToBinary(Byte[] data)
{
    return string.Join(" ", data.Select(byt => Convert.ToString(byt, 2).PadLeft(8, '0')));
}

// Use any sort of encoding you like. 
var binaryString = ToBinary(ConvertToByteArray("Welcome, World!", Encoding.ASCII));

How to change the style of the title attribute inside an anchor tag?

I have found the answer here: http://www.webdesignerdepot.com/2012/11/how-to-create-a-simple-css3-tooltip/

my own code goes like this, I have changed the attribute name, if you maintain the title name for the attribute you end up having two popups for the same text, another change is that my text on hovering displays underneath the exposed text.

_x000D_
_x000D_
.tags {
  display: inline;
  position: relative;
}

.tags:hover:after {
  background: #333;
  background: rgba(0, 0, 0, .8);
  border-radius: 5px;
  bottom: -34px;
  color: #fff;
  content: attr(gloss);
  left: 20%;
  padding: 5px 15px;
  position: absolute;
  z-index: 98;
  width: 350px;
}

.tags:hover:before {
  border: solid;
  border-color: #333 transparent;
  border-width: 0 6px 6px 6px;
  bottom: -4px;
  content: "";
  left: 50%;
  position: absolute;
  z-index: 99;
}
_x000D_
<a class="tags" gloss="Text shown on hovering">Exposed text</a>
_x000D_
_x000D_
_x000D_

Django Server Error: port is already in use

Click the arrow in the screenshot and find the bash with already running Django server. You were getting the message because your server was already running and you tried to start the server again.

enter image description here

How to install maven on redhat linux

Installing maven in Amazon Linux / redhat

--> sudo wget http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-apache-maven.repo -O /etc/yum.repos.d/epel-apache-maven.repo

--> sudo sed -i s/\$releasever/6/g /etc/yum.repos.d/epel-apache-maven.repo

-->sudo yum install -y apache-maven

--> mvn --version

Output looks like


Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d; 2017-10-18T07:58:13Z) Maven home: /usr/share/apache-maven Java version: 1.8.0_171, vendor: Oracle Corporation Java home: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.171-8.b10.amzn2.x86_64/jre Default locale: en_US, platform encoding: UTF-8 OS name: "linux", version: "4.14.47-64.38.amzn2.x86_64", arch: "amd64", family: "unix"

*If its thrown error related to java please follow the below step to update java 8 *

Installing java 8 in amazon linux/redhat

--> yum search java | grep openjdk

--> yum install java-1.8.0-openjdk-headless.x86_64

--> yum install java-1.8.0-openjdk-devel.x86_64

--> update-alternatives --config java #pick java 1.8 and press 1

--> update-alternatives --config javac #pick java 1.8 and press 2

Thank You

How do I change the owner of a SQL Server database?

Here is a way to change the owner on ALL DBS (excluding System)

EXEC sp_msforeachdb'
USE [?]
IF ''?'' <> ''master'' AND ''?'' <> ''model'' AND ''?'' <> ''msdb'' AND ''?'' <> ''tempdb''
BEGIN
 exec sp_changedbowner ''sa''
END
'

How to determine one year from now in Javascript

In very simple way. use this code.

// define function 
function nextYearDate(date1) {
    var date2 = new Date(date1);
    var date3 = date2.setDate(date2.getDate() - 1);
    var date = new Date(date3);
    var day = date.getDate();
    var month = date.getMonth()+1;
    var year = date.getFullYear()+1;
    var newdate = year + '-' + (month < 10 ? '0' : '') + month + '-' + (day < 10 ? '0' : '') + day;
    $("#next_date").val(newdate);
}
// call function.
<input type="date" name="current_date" id="current_date" value="" onblur="nextYearDate(this.value);" />

<input type="date" name="next_date" id="next_date" value="" onblur="nextYearDate(this.value);" />

How To Show And Hide Input Fields Based On Radio Button Selection

Use display:none/block, instead of visibility, and add a margin-top/bottom for the space you want to see ONLY when the inputs are shown

 function yesnoCheck() {
        if (document.getElementById('yesCheck').checked) {
           document.getElementById('ifYes').style.display = 'block';
        } else {
           document.getElementById('ifYes').style.display = 'none';
        }
    }

and your HTML line for the ifYes tag

<div id="ifYes" style="display:none;margin-top:3%;">If yes, explain:

Remove values from select list based on condition

For clear all options en Important en FOR : remove(0) - Important: 0

var select = document.getElementById("element_select");
var length = select.length;
for (i = 0; i < length; i++) {
     select.remove(0);
 //  or
 //  select.options[0] = null;
} 

Each GROUP BY expression must contain at least one column that is not an outer reference

Well, as it was said before, you can't GROUP by literals, I think that you are confused cause you can ORDER by 1, 2, 3. When you use functions as your columns, you need to GROUP by the same expression. Besides, the HAVING clause is wrong, you can only use what is in the agreggations. In this case, your query should be like this:

SELECT 
LEFT(SUBSTRING(batchinfo.datapath, PATINDEX('%[0-9][0-9][0-9]%', batchinfo.datapath), 8000), PATINDEX('%[^0-9]%', SUBSTRING(batchinfo.datapath, PATINDEX('%[0-9][0-9][0-9]%', batchinfo.datapath), 8000))-1),
qvalues.name,
qvalues.compound,
MAX(qvalues.rid) MaxRid
FROM batchinfo join qvalues 
ON batchinfo.rowid=qvalues.rowid
WHERE LEN(datapath)>4
GROUP BY 
LEFT(SUBSTRING(batchinfo.datapath, PATINDEX('%[0-9][0-9][0-9]%', batchinfo.datapath), 8000), PATINDEX('%[^0-9]%', SUBSTRING(batchinfo.datapath, PATINDEX('%[0-9][0-9][0-9]%', batchinfo.datapath), 8000))-1),
qvalues.name,
qvalues.compound

How to save an HTML5 Canvas as an image on a server?

Send canvas image to PHP:

var photo = canvas.toDataURL('image/jpeg');                
$.ajax({
  method: 'POST',
  url: 'photo_upload.php',
  data: {
    photo: photo
  }
});

Here's PHP script:
photo_upload.php

<?php

    $data = $_POST['photo'];
    list($type, $data) = explode(';', $data);
    list(, $data)      = explode(',', $data);
    $data = base64_decode($data);

    mkdir($_SERVER['DOCUMENT_ROOT'] . "/photos");

    file_put_contents($_SERVER['DOCUMENT_ROOT'] . "/photos/".time().'.png', $data);
    die;
?>

extract the date part from DateTime in C#

DateTime is a DataType which is used to store both Date and Time. But it provides Properties to get the Date Part.

You can get the Date part from Date Property.

http://msdn.microsoft.com/en-us/library/system.datetime.date.aspx

DateTime date1 = new DateTime(2008, 6, 1, 7, 47, 0);
Console.WriteLine(date1.ToString());

// Get date-only portion of date, without its time.
DateTime dateOnly = date1.Date;
// Display date using short date string.
Console.WriteLine(dateOnly.ToString("d"));
// Display date using 24-hour clock.
Console.WriteLine(dateOnly.ToString("g"));
Console.WriteLine(dateOnly.ToString("MM/dd/yyyy HH:mm"));   
// The example displays the following output to the console:
//       6/1/2008 7:47:00 AM
//       6/1/2008
//       6/1/2008 12:00 AM
//       06/01/2008 00:00

How to delete/remove nodes on Firebase

The problem is that you call remove on the root of your Firebase:

ref = new Firebase("myfirebase.com")
ref.remove();

This will remove the entire Firebase through the API.

You'll typically want to remove specific child nodes under it though, which you do with:

ref.child(key).remove();

includes() not working in all browsers

One more solution is to use contains which will return true or false

_.contains($(".right-tree").css("background-image"), "stage1")

Hope this helps

When to use cla(), clf() or close() for clearing a plot in matplotlib?

There is just a caveat that I discovered today. If you have a function that is calling a plot a lot of times you better use plt.close(fig) instead of fig.clf() somehow the first does not accumulate in memory. In short if memory is a concern use plt.close(fig) (Although it seems that there are better ways, go to the end of this comment for relevant links).

So the the following script will produce an empty list:

for i in range(5):
    fig = plot_figure()
    plt.close(fig)
# This returns a list with all figure numbers available
print(plt.get_fignums())

Whereas this one will produce a list with five figures on it.

for i in range(5):
    fig = plot_figure()
    fig.clf()
# This returns a list with all figure numbers available
print(plt.get_fignums())

From the documentation above is not clear to me what is the difference between closing a figure and closing a window. Maybe that will clarify.

If you want to try a complete script there you have:

import numpy as np
import matplotlib.pyplot as plt
x = np.arange(1000)
y = np.sin(x)

for i in range(5):
    fig = plt.figure()
    ax = fig.add_subplot(1, 1, 1)
    ax.plot(x, y)
    plt.close(fig)

print(plt.get_fignums())

for i in range(5):
    fig = plt.figure()
    ax = fig.add_subplot(1, 1, 1)
    ax.plot(x, y)
    fig.clf()

print(plt.get_fignums())

If memory is a concern somebody already posted a work-around in SO see: Create a figure that is reference counted

How can I change the color of pagination dots of UIPageControl?

In iOS 6 you can set the tint color of UIPageControl:

There are 2 new properties:

  • pageIndicatorTintColor
  • currentPageIndicatorTintColor

You can also use the appearance API to change the tint color of all page indicators.

If you are targeting iOS 5 make sure it doesn't crash:

if ([pageControl respondsToSelector:@selector(setPageIndicatorTintColor:)]) {
    pageControl.pageIndicatorTintColor = [UIColor whiteColor];
}

In Java how does one turn a String into a char or a char into a String?

I like to do something like this:

String oneLetter = "" + someChar;

Remove whitespaces inside a string in javascript

You can use Strings replace method with a regular expression.

"Hello World ".replace(/ /g, "");

The replace() method returns a new string with some or all matches of a pattern replaced by a replacement. The pattern can be a string or a RegExp

RegExp

  • / / - Regular expression matching spaces

  • g - Global flag; find all matches rather than stopping after the first match

_x000D_
_x000D_
const str = "H    e            l l       o  World! ".replace(/ /g, "");_x000D_
document.getElementById("greeting").innerText = str;
_x000D_
<p id="greeting"><p>
_x000D_
_x000D_
_x000D_

How to add screenshot to READMEs in github repository?

First, create a directory(folder) in the root of your local repo that will contain the screenshots you want added. Let’s call the name of this directory screenshots. Place the images (JPEG, PNG, GIF,` etc) you want to add into this directory.

Android Studio Workspace Screenshot

Secondly, you need to add a link to each image into your README. So, if I have images named 1_ArtistsActivity.png and 2_AlbumsActivity.png in my screenshots directory, I will add their links like so:

 <img src="screenshots/1_ArtistsActivity.png" height="400" alt="Screenshot"/> <img src=“screenshots/2_AlbumsActivity.png" height="400" alt="Screenshot"/>

If you want each screenshot on a separate line, write their links on separate lines. However, it’s better if you write all the links in one line, separated by space only. It might actually not look too good but by doing so GitHub automatically arranges them for you.

Finally, commit your changes and push it!

Putting GridView data in a DataTable

Copying Grid to datatable

        if (GridView.Rows.Count != 0)
        {
            //Forloop for header
            for (int i = 0; i < GridView.HeaderRow.Cells.Count; i++)
            {
                dt.Columns.Add(GridView.HeaderRow.Cells[i].Text);
            }
            //foreach for datarow
            foreach (GridViewRow row in GridView.Rows)
            {
                DataRow dr = dt.NewRow();
                for (int j = 0; j < row.Cells.Count; j++)
                {
                    dr[GridView.HeaderRow.Cells[j].Text] = row.Cells[j].Text;
                }
                dt.Rows.Add(dr);
            }
            //Loop for footer
            if (GridView.FooterRow.Cells.Count != 0)
            {
                DataRow dr = dt.NewRow();
                for (int i = 0; i < GridView.FooterRow.Cells.Count; i++)
                {
                    //You have to re-do the work if you did anything in databound for footer.  
                }
                dt.Rows.Add(dr);
            }
            dt.TableName = "tb";
        }

How to insert multiple rows from array using CodeIgniter framework?

You can do it with several ways in codeigniter e.g.

First By loop

foreach($myarray as $row)
{
   $data = array("first"=>$row->first,"second"=>$row->sec);
   $this->db->insert('table_name',$data);
}

Second -- By insert batch

$data = array(
       array(
          'first' => $myarray[0]['first'] ,
          'second' => $myarray[0]['sec'],
        ),
       array(
          'first' => $myarray[1]['first'] ,
          'second' => $myarray[1]['sec'],
        ),
    );

    $this->db->insert_batch('table_name', $data);

Third way -- By multiple value pass

$sql = array(); 
foreach( $myarray as $row ) {
    $sql[] = '("'.mysql_real_escape_string($row['first']).'", '.$row['sec'].')';
}
mysql_query('INSERT INTO table (first, second) VALUES '.implode(',', $sql));

Why are empty catch blocks a bad idea?

Empty catch blocks are usually put in because the coder doesn't really know what they are doing. At my organization, an empty catch block must include a comment as to why doing nothing with the exception is a good idea.

On a related note, most people don't know that a try{} block can be followed with either a catch{} or a finally{}, only one is required.

Is iterating ConcurrentHashMap values thread safe?

You may use this class to test two accessing threads and one mutating the shared instance of ConcurrentHashMap:

import java.util.Map;
import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConcurrentMapIteration
{
  private final Map<String, String> map = new ConcurrentHashMap<String, String>();

  private final static int MAP_SIZE = 100000;

  public static void main(String[] args)
  {
    new ConcurrentMapIteration().run();
  }

  public ConcurrentMapIteration()
  {
    for (int i = 0; i < MAP_SIZE; i++)
    {
      map.put("key" + i, UUID.randomUUID().toString());
    }
  }

  private final ExecutorService executor = Executors.newCachedThreadPool();

  private final class Accessor implements Runnable
  {
    private final Map<String, String> map;

    public Accessor(Map<String, String> map)
    {
      this.map = map;
    }

    @Override
    public void run()
    {
      for (Map.Entry<String, String> entry : this.map.entrySet())
      {
        System.out.println(
            Thread.currentThread().getName() + " - [" + entry.getKey() + ", " + entry.getValue() + ']'
        );
      }
    }
  }

  private final class Mutator implements Runnable
  {

    private final Map<String, String> map;
    private final Random random = new Random();

    public Mutator(Map<String, String> map)
    {
      this.map = map;
    }

    @Override
    public void run()
    {
      for (int i = 0; i < 100; i++)
      {
        this.map.remove("key" + random.nextInt(MAP_SIZE));
        this.map.put("key" + random.nextInt(MAP_SIZE), UUID.randomUUID().toString());
        System.out.println(Thread.currentThread().getName() + ": " + i);
      }
    }
  }

  private void run()
  {
    Accessor a1 = new Accessor(this.map);
    Accessor a2 = new Accessor(this.map);
    Mutator m = new Mutator(this.map);

    executor.execute(a1);
    executor.execute(m);
    executor.execute(a2);
  }
}

No exception will be thrown.

Sharing the same iterator between accessor threads can lead to deadlock:

import java.util.Iterator;
import java.util.Map;
import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConcurrentMapIteration
{
  private final Map<String, String> map = new ConcurrentHashMap<String, String>();
  private final Iterator<Map.Entry<String, String>> iterator;

  private final static int MAP_SIZE = 100000;

  public static void main(String[] args)
  {
    new ConcurrentMapIteration().run();
  }

  public ConcurrentMapIteration()
  {
    for (int i = 0; i < MAP_SIZE; i++)
    {
      map.put("key" + i, UUID.randomUUID().toString());
    }
    this.iterator = this.map.entrySet().iterator();
  }

  private final ExecutorService executor = Executors.newCachedThreadPool();

  private final class Accessor implements Runnable
  {
    private final Iterator<Map.Entry<String, String>> iterator;

    public Accessor(Iterator<Map.Entry<String, String>> iterator)
    {
      this.iterator = iterator;
    }

    @Override
    public void run()
    {
      while(iterator.hasNext()) {
        Map.Entry<String, String> entry = iterator.next();
        try
        {
          String st = Thread.currentThread().getName() + " - [" + entry.getKey() + ", " + entry.getValue() + ']';
        } catch (Exception e)
        {
          e.printStackTrace();
        }

      }
    }
  }

  private final class Mutator implements Runnable
  {

    private final Map<String, String> map;
    private final Random random = new Random();

    public Mutator(Map<String, String> map)
    {
      this.map = map;
    }

    @Override
    public void run()
    {
      for (int i = 0; i < 100; i++)
      {
        this.map.remove("key" + random.nextInt(MAP_SIZE));
        this.map.put("key" + random.nextInt(MAP_SIZE), UUID.randomUUID().toString());
      }
    }
  }

  private void run()
  {
    Accessor a1 = new Accessor(this.iterator);
    Accessor a2 = new Accessor(this.iterator);
    Mutator m = new Mutator(this.map);

    executor.execute(a1);
    executor.execute(m);
    executor.execute(a2);
  }
}

As soon as you start sharing the same Iterator<Map.Entry<String, String>> among accessor and mutator threads java.lang.IllegalStateExceptions will start popping up.

import java.util.Iterator;
import java.util.Map;
import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConcurrentMapIteration
{
  private final Map<String, String> map = new ConcurrentHashMap<String, String>();
  private final Iterator<Map.Entry<String, String>> iterator;

  private final static int MAP_SIZE = 100000;

  public static void main(String[] args)
  {
    new ConcurrentMapIteration().run();
  }

  public ConcurrentMapIteration()
  {
    for (int i = 0; i < MAP_SIZE; i++)
    {
      map.put("key" + i, UUID.randomUUID().toString());
    }
    this.iterator = this.map.entrySet().iterator();
  }

  private final ExecutorService executor = Executors.newCachedThreadPool();

  private final class Accessor implements Runnable
  {
    private final Iterator<Map.Entry<String, String>> iterator;

    public Accessor(Iterator<Map.Entry<String, String>> iterator)
    {
      this.iterator = iterator;
    }

    @Override
    public void run()
    {
      while (iterator.hasNext())
      {
        Map.Entry<String, String> entry = iterator.next();
        try
        {
          String st =
              Thread.currentThread().getName() + " - [" + entry.getKey() + ", " + entry.getValue() + ']';
        } catch (Exception e)
        {
          e.printStackTrace();
        }

      }
    }
  }

  private final class Mutator implements Runnable
  {

    private final Random random = new Random();

    private final Iterator<Map.Entry<String, String>> iterator;

    private final Map<String, String> map;

    public Mutator(Map<String, String> map, Iterator<Map.Entry<String, String>> iterator)
    {
      this.map = map;
      this.iterator = iterator;
    }

    @Override
    public void run()
    {
      while (iterator.hasNext())
      {
        try
        {
          iterator.remove();
          this.map.put("key" + random.nextInt(MAP_SIZE), UUID.randomUUID().toString());
        } catch (Exception ex)
        {
          ex.printStackTrace();
        }
      }

    }
  }

  private void run()
  {
    Accessor a1 = new Accessor(this.iterator);
    Accessor a2 = new Accessor(this.iterator);
    Mutator m = new Mutator(map, this.iterator);

    executor.execute(a1);
    executor.execute(m);
    executor.execute(a2);
  }
}

JavaScript console.log causes error: "Synchronous XMLHttpRequest on the main thread is deprecated..."

Visual Studio 2015/2017's live debugger is injecting code that contains the deprecated call.

Bloomberg Open API

The API's will provide full access to LIVE data, and developers can thus provide applications and develop against the API without paying licencing fees. Consumers will pay for any data received from the apps provided by third party developers, and so BB will grow their audience and revenue in that way.

NOTE: Bloomberg is offering this programming interface (BLPAPI) under a free-use license. This license does not include nor provide access to any Bloomberg data or content.

Source: http://www.openbloomberg.com/open-api/

Add & delete view from Layout

This is the best way

LinearLayout lp = new LinearLayout(this);
lp.addView(new Button(this));
lp.addView(new ImageButton(this));
// Now remove them 
lp.removeViewAt(0); // and so on

If you have xml layout then no need to add dynamically.just call

lp.removeViewAt(0);

How to get JSON from URL in JavaScript?

Define a function like:

fetchRestaurants(callback) {
    fetch(`http://www.restaurants.com`)
       .then(response => response.json())
       .then(json => callback(null, json.restaurants))
       .catch(error => callback(error, null))
}

Then use it like this:

fetchRestaurants((error, restaurants) => {
    if (error) 
        console.log(error)
    else 
        console.log(restaurants[0])

});

Understanding the map function

map creates a new list by applying a function to every element of the source:

xs = [1, 2, 3]

# all of those are equivalent — the output is [2, 4, 6]
# 1. map
ys = map(lambda x: x * 2, xs)
# 2. list comprehension
ys = [x * 2 for x in xs]
# 3. explicit loop
ys = []
for x in xs:
    ys.append(x * 2)

n-ary map is equivalent to zipping input iterables together and then applying the transformation function on every element of that intermediate zipped list. It's not a Cartesian product:

xs = [1, 2, 3]
ys = [2, 4, 6]

def f(x, y):
    return (x * 2, y // 2)

# output: [(2, 1), (4, 2), (6, 3)]
# 1. map
zs = map(f, xs, ys)
# 2. list comp
zs = [f(x, y) for x, y in zip(xs, ys)]
# 3. explicit loop
zs = []
for x, y in zip(xs, ys):
    zs.append(f(x, y))

I've used zip here, but map behaviour actually differs slightly when iterables aren't the same size — as noted in its documentation, it extends iterables to contain None.

How can I upgrade NumPy?

If you don't encounter any permission errors with

pip install -U numpy

try:

pip install --user -U numpy

How to plot ROC curve in Python

I have made a simple function included in a package for the ROC curve. I just started practicing machine learning so please also let me know if this code has any problem!

Have a look at the github readme file for more details! :)

https://github.com/bc123456/ROC

from sklearn.metrics import confusion_matrix, accuracy_score, roc_auc_score, roc_curve
import matplotlib.pyplot as plt
import seaborn as sns
import numpy as np

def plot_ROC(y_train_true, y_train_prob, y_test_true, y_test_prob):
    '''
    a funciton to plot the ROC curve for train labels and test labels.
    Use the best threshold found in train set to classify items in test set.
    '''
    fpr_train, tpr_train, thresholds_train = roc_curve(y_train_true, y_train_prob, pos_label =True)
    sum_sensitivity_specificity_train = tpr_train + (1-fpr_train)
    best_threshold_id_train = np.argmax(sum_sensitivity_specificity_train)
    best_threshold = thresholds_train[best_threshold_id_train]
    best_fpr_train = fpr_train[best_threshold_id_train]
    best_tpr_train = tpr_train[best_threshold_id_train]
    y_train = y_train_prob > best_threshold

    cm_train = confusion_matrix(y_train_true, y_train)
    acc_train = accuracy_score(y_train_true, y_train)
    auc_train = roc_auc_score(y_train_true, y_train)

    print 'Train Accuracy: %s ' %acc_train
    print 'Train AUC: %s ' %auc_train
    print 'Train Confusion Matrix:'
    print cm_train

    fig = plt.figure(figsize=(10,5))
    ax = fig.add_subplot(121)
    curve1 = ax.plot(fpr_train, tpr_train)
    curve2 = ax.plot([0, 1], [0, 1], color='navy', linestyle='--')
    dot = ax.plot(best_fpr_train, best_tpr_train, marker='o', color='black')
    ax.text(best_fpr_train, best_tpr_train, s = '(%.3f,%.3f)' %(best_fpr_train, best_tpr_train))
    plt.xlim([0.0, 1.0])
    plt.ylim([0.0, 1.0])
    plt.xlabel('False Positive Rate')
    plt.ylabel('True Positive Rate')
    plt.title('ROC curve (Train), AUC = %.4f'%auc_train)

    fpr_test, tpr_test, thresholds_test = roc_curve(y_test_true, y_test_prob, pos_label =True)

    y_test = y_test_prob > best_threshold

    cm_test = confusion_matrix(y_test_true, y_test)
    acc_test = accuracy_score(y_test_true, y_test)
    auc_test = roc_auc_score(y_test_true, y_test)

    print 'Test Accuracy: %s ' %acc_test
    print 'Test AUC: %s ' %auc_test
    print 'Test Confusion Matrix:'
    print cm_test

    tpr_score = float(cm_test[1][1])/(cm_test[1][1] + cm_test[1][0])
    fpr_score = float(cm_test[0][1])/(cm_test[0][0]+ cm_test[0][1])

    ax2 = fig.add_subplot(122)
    curve1 = ax2.plot(fpr_test, tpr_test)
    curve2 = ax2.plot([0, 1], [0, 1], color='navy', linestyle='--')
    dot = ax2.plot(fpr_score, tpr_score, marker='o', color='black')
    ax2.text(fpr_score, tpr_score, s = '(%.3f,%.3f)' %(fpr_score, tpr_score))
    plt.xlim([0.0, 1.0])
    plt.ylim([0.0, 1.0])
    plt.xlabel('False Positive Rate')
    plt.ylabel('True Positive Rate')
    plt.title('ROC curve (Test), AUC = %.4f'%auc_test)
    plt.savefig('ROC', dpi = 500)
    plt.show()

    return best_threshold

A sample roc graph produced by this code

Composer could not find a composer.json

To install composer and add to your global path:

curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

run these in terminal. It does say if you get an error that usr doesn't exist, you do need to manually make it. I know an answer was selected, so this is for anyone who may see this in the future, as i am sometimes, and don't want to be advised to visit yet another site. Its simple just two lines, might have to be in sudo if you have permission error

Change status bar text color to light in iOS 9 with Objective-C

  1. Add a key in your info.plist file UIViewControllerBasedStatusBarAppearance and set it to YES.

  2. In viewDidLoad method of your ViewController add a method call:

    [self setNeedsStatusBarAppearanceUpdate];
    
  3. Then paste the following method in viewController file:

    - (UIStatusBarStyle)preferredStatusBarStyle
    { 
        return UIStatusBarStyleLightContent; 
    }
    

Find index of a value in an array

int keyIndex = words.TakeWhile(w => !w.IsKey).Count();

Retrieving Android API version programmatically

SDK.INT is supported for Android 1.6 and up

SDK is supported for all versions

So I do:

String sdk_version_number = android.os.Build.VERSION.SDK;

Credits to: CommonsWare over this answer

Get folder name of the file in Python

you can use pathlib

from pathlib import Path
Path(r"C:\folder1\folder2\filename.xml").parts[-2]

The output of the above was this:

'folder2'

Git SSH error: "Connect to host: Bad file number"

In my case simply restarting the WiFi router helped.

Get all parameters from JSP page

The fastest way should be:

<%@ page import="java.util.Map" %>
Map<String, String[]> parameters = request.getParameterMap();
for (Map.Entry<String, String[]> entry : parameters.entrySet()) {
    if (entry.getKey().startsWith("question")) {
        String[] values = entry.getValue();
        // etc.

Note that you can't do:

for (Map.Entry<String, String[]> entry : 
     request.getParameterMap().entrySet()) { // WRONG!

for reasons explained here.

How to specify 64 bit integers in c

Try an LL suffix on the number, the compiler may be casting it to an intermediate type as part of the parse. See http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html

long long int i2 = 0x0000444400004444LL;

Additionally, the the compiler is discarding the leading zeros, so 0x000044440000 is becoming 0x44440000, which is a perfectly acceptable 32-bit integer (which is why you aren't seeing any warnings prior to f2).

How to position two elements side by side using CSS

Just use the float style. Put your google map iframe in a div class, and the paragraph in another div class, then apply the following CSS styles to those div classes(don't forget to clear the blocks after float effect, to not make the blocks trouble below them):

css

.google_map{
    width:55%;
    margin-right:2%;
    float: left;
}
.google_map iframe{
   width:100%;
}
.paragraph {
    width:42%;
    float: left;
}
.clearfix{
    clear:both
}

html

<div class="google_map">
      <iframe></iframe>
</div>
<div class="paragraph">
      <p></p>
</div>
<div class="clearfix"></div>

vue.js 2 how to watch store values from vuex

You should not use component's watchers to listen to state change. I recommend you to use getters functions and then map them inside your component.

import { mapGetters } from 'vuex'

export default {
  computed: {
    ...mapGetters({
      myState: 'getMyState'
    })
  }
}

In your store:

const getters = {
  getMyState: state => state.my_state
}

You should be able to listen to any changes made to your store by using this.myState in your component.

https://vuex.vuejs.org/en/getters.html#the-mapgetters-helper

Google Play app description formatting

<br> seems to be the best and only way that currently works on the app version to create a new line break. I have tried it successfully in a review, as well as unsuccessfully tried all other Unicode/HTML newline-related characters that the Wikipedia page for newlines would tell me. I used <br> with | immediately on either side, using no closing tag, and it magically created a single line break without revealing the source or screwing anything up.

TLDR: <br> lets you successfully utilize single line breaks in Google Play app -- unlike everything else I tried (a lot).

P.S. I have no clue how to make the thing show source instead of being used as source. !^( Now I do, and I know it works on both the desktop and mobile sites. !!

Additionally, upon searching for how to make it show the source, I stumbled upon this. <del></del>

How to initialize List<String> object in Java?

List is an interface, and you can not initialize an interface. Instantiate an implementing class instead.

Like:

List<String> abc = new ArrayList<String>();
List<String> xyz = new LinkedList<String>();

How do I setup the InternetExplorerDriver so it works

public class NavigateUsingAllBrowsers {


public static void main(String[] args) {

WebDriver driverFF= new FirefoxDriver();
driverFF.navigate().to("http://www.firefox.com");


File file =new File("C:/Users/mkv/workspace/ServerDrivers/IEDriverServer.exe");
System.setProperty("webdriver.ie.driver", file.getAbsolutePath());
WebDriver driverIE=new InternetExplorerDriver();
driverIE.navigate().to("http://www.msn.com");

// Download Chrome Driver from http://code.google.com/p/chromedriver/downloads/list

file =new File("C:/Users/mkv/workspace/ServerDrivers/ChromeDriver.exe");
System.setProperty("webdriver.chrome.driver", file.getAbsolutePath());
WebDriver driverChrome=new ChromeDriver();
driverChrome.navigate().to("http://www.chrome.com");

}

}

Slick.js: Get current and total slides (ie. 3/5)

Using the previous method with more than 1 slide at time was giving me the wrong total so I've used the "dotsClass", like this (on v1.7.1):

// JS

var slidesPerPage = 6

$(".slick").on("init", function(event, slick){
   maxPages = Math.ceil(slick.slideCount/slidesPerPage);
   $(this).find('.slider-paging-number li').append('/ '+maxPages);
});

$(".slick").slick({
   slidesToShow: slidesPerPage,
   slidesToScroll: slidesPerPage,
   arrows: false,
   autoplay: true,
   dots: true,
   infinite: true,
   dotsClass: 'slider-paging-number'
});

// CSS

ul.slider-paging-number {
    list-style: none;
    li {
        display: none;
        &.slick-active {
            display: inline-block;
        }
        button {
            background: none;
            border: none;
        }
    }
}

Difference between Math.Floor() and Math.Truncate()

Math.Floor() :

It gives the largest integer less than or equal to the given number.

    Math.Floor(3.45) =3
    Math.Floor(-3.45) =-4

Math.Truncate():

It removes the decimal places of the number and replace with zero

Math.Truncate(3.45)=3
 Math.Truncate(-3.45)=-3

Also from above examples we can see that floor and truncate are same for positive numbers.

How can I check if a program exists from a Bash script?

My setup for a Debian server:

I had the problem when multiple packages contained the same name.

For example apache2. So this was my solution:

function _apt_install() {
    apt-get install -y $1 > /dev/null
}

function _apt_install_norecommends() {
    apt-get install -y --no-install-recommends $1 > /dev/null
}
function _apt_available() {
    if [ `apt-cache search $1 | grep -o "$1" | uniq | wc -l` = "1" ]; then
        echo "Package is available : $1"
        PACKAGE_INSTALL="1"
    else
        echo "Package $1 is NOT available for install"
        echo  "We can not continue without this package..."
        echo  "Exitting now.."
        exit 0
    fi
}
function _package_install {
    _apt_available $1
    if [ "${PACKAGE_INSTALL}" = "1" ]; then
        if [ "$(dpkg-query -l $1 | tail -n1 | cut -c1-2)" = "ii" ]; then
             echo  "package is already_installed: $1"
        else
            echo  "installing package : $1, please wait.."
            _apt_install $1
            sleep 0.5
        fi
    fi
}

function _package_install_no_recommends {
    _apt_available $1
    if [ "${PACKAGE_INSTALL}" = "1" ]; then
        if [ "$(dpkg-query -l $1 | tail -n1 | cut -c1-2)" = "ii" ]; then
             echo  "package is already_installed: $1"
        else
            echo  "installing package : $1, please wait.."
            _apt_install_norecommends $1
            sleep 0.5
        fi
    fi
}

Angularjs checkbox checked by default on load and disables Select list when checked

If you use ng-model, you don't want to also use ng-checked. Instead just initialize the model variable to true. Normally you would do this in a controller that is managing your page (add one). In your fiddle I just did the initialization in an ng-init attribute for demonstration purposes.

http://jsfiddle.net/UTULc/

<div ng-app="">
  Send to Office: <input type="checkbox" ng-model="checked" ng-init="checked=true"><br/>
  <select id="transferTo" ng-disabled="checked">
    <option>Tech1</option>
    <option>Tech2</option>
  </select>
</div>

Why does an image captured using camera intent gets rotated on some devices on Android?

By combining Jason Robinson's answer with Felix's answer and filling the missing parts, here is the final complete solution for this issue that will do the following after testing it on Android Android 4.1 (Jelly Bean), Android 4.4 (KitKat) and Android 5.0 (Lollipop).

Steps

  1. Scale down the image if it was bigger than 1024x1024.

  2. Rotate the image to the right orientation only if it was rotate 90, 180 or 270 degree.

  3. Recycle the rotated image for memory purposes.

Here is the code part:

Call the following method with the current Context and the image URI that you want to fix

/**
 * This method is responsible for solving the rotation issue if exist. Also scale the images to
 * 1024x1024 resolution
 *
 * @param context       The current context
 * @param selectedImage The Image URI
 * @return Bitmap image results
 * @throws IOException
 */
public static Bitmap handleSamplingAndRotationBitmap(Context context, Uri selectedImage)
        throws IOException {
    int MAX_HEIGHT = 1024;
    int MAX_WIDTH = 1024;

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    InputStream imageStream = context.getContentResolver().openInputStream(selectedImage);
    BitmapFactory.decodeStream(imageStream, null, options);
    imageStream.close();

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, MAX_WIDTH, MAX_HEIGHT);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    imageStream = context.getContentResolver().openInputStream(selectedImage);
    Bitmap img = BitmapFactory.decodeStream(imageStream, null, options);

    img = rotateImageIfRequired(context, img, selectedImage);
    return img;
}

Here is the CalculateInSampleSize method from the pre mentioned source:

/**
  * Calculate an inSampleSize for use in a {@link BitmapFactory.Options} object when decoding
  * bitmaps using the decode* methods from {@link BitmapFactory}. This implementation calculates
  * the closest inSampleSize that will result in the final decoded bitmap having a width and
  * height equal to or larger than the requested width and height. This implementation does not
  * ensure a power of 2 is returned for inSampleSize which can be faster when decoding but
  * results in a larger bitmap which isn't as useful for caching purposes.
  *
  * @param options   An options object with out* params already populated (run through a decode*
  *                  method with inJustDecodeBounds==true
  * @param reqWidth  The requested width of the resulting bitmap
  * @param reqHeight The requested height of the resulting bitmap
  * @return The value to be used for inSampleSize
  */
private static int calculateInSampleSize(BitmapFactory.Options options,
                                         int reqWidth, int reqHeight) {
    // Raw height and width of image
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {

        // Calculate ratios of height and width to requested height and width
        final int heightRatio = Math.round((float) height / (float) reqHeight);
        final int widthRatio = Math.round((float) width / (float) reqWidth);

        // Choose the smallest ratio as inSampleSize value, this will guarantee a final image
        // with both dimensions larger than or equal to the requested height and width.
        inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;

        // This offers some additional logic in case the image has a strange
        // aspect ratio. For example, a panorama may have a much larger
        // width than height. In these cases the total pixels might still
        // end up being too large to fit comfortably in memory, so we should
        // be more aggressive with sample down the image (=larger inSampleSize).

        final float totalPixels = width * height;

        // Anything more than 2x the requested pixels we'll sample down further
        final float totalReqPixelsCap = reqWidth * reqHeight * 2;

        while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
            inSampleSize++;
        }
    }
    return inSampleSize;
}

Then comes the method that will check the current image orientation to decide the rotation angle

 /**
 * Rotate an image if required.
 *
 * @param img           The image bitmap
 * @param selectedImage Image URI
 * @return The resulted Bitmap after manipulation
 */
private static Bitmap rotateImageIfRequired(Context context, Bitmap img, Uri selectedImage) throws IOException {

InputStream input = context.getContentResolver().openInputStream(selectedImage);
ExifInterface ei;
if (Build.VERSION.SDK_INT > 23)
    ei = new ExifInterface(input);
else
    ei = new ExifInterface(selectedImage.getPath());

    int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

    switch (orientation) {
        case ExifInterface.ORIENTATION_ROTATE_90:
            return rotateImage(img, 90);
        case ExifInterface.ORIENTATION_ROTATE_180:
            return rotateImage(img, 180);
        case ExifInterface.ORIENTATION_ROTATE_270:
            return rotateImage(img, 270);
        default:
            return img;
    }
}

Finally the rotation method itself

private static Bitmap rotateImage(Bitmap img, int degree) {
    Matrix matrix = new Matrix();
    matrix.postRotate(degree);
    Bitmap rotatedImg = Bitmap.createBitmap(img, 0, 0, img.getWidth(), img.getHeight(), matrix, true);
    img.recycle();
    return rotatedImg;
}

-Don't forget to vote up for those guys answers for their efforts and Shirish Herwade who asked this helpful question.

Check if a parameter is null or empty in a stored procedure

I use coalesce:

IF ( COALESCE( @PreviousStartDate, '' ) = '' ) ...

What should my Objective-C singleton look like?

To extend the example from @robbie-hanson ...

static MySingleton* sharedSingleton = nil;

+ (void)initialize {
    static BOOL initialized = NO;
    if (!initialized) {
        initialized = YES;
        sharedSingleton = [[self alloc] init];
    }
}

- (id)init {
    self = [super init];
    if (self) {
        // Member initialization here.
    }
    return self;
}

How to remove tab indent from several lines in IDLE?

If you're using IDLE, you can use Ctrl+] to indent and Ctrl+[ to unindent.

Is ConfigurationManager.AppSettings available in .NET Core 2.0?

You can use Configuration to resolve this.

Ex (Startup.cs):

You can pass by DI to the controllers after this implementation.

public class Startup
{
    public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
        .SetBasePath(env.ContentRootPath)
        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);

        Configuration = builder.Build();

    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {

        var microserviceName = Configuration["microserviceName"];

       services.AddSingleton(Configuration);

       ...
    }