Programs & Examples On #Brackets

Brackets are tall punctuation marks used in matched pairs within text, to set apart or interject other text. They have a variety of meanings in different programming languages. DO NOT USE THIS for the IDE, use [adobe-brackets] instead.

Get the string within brackets in Python

How about this ? Example illusrated using a file:

f = open('abc.log','r')
content = f.readlines()
for line in content:
    m = re.search(r"\[(.*?)\]", line)
    print m.group(1)
    

Hope this helps:

Magic regex : \[(.*?)\]

Explanation:

\[ : [ is a meta char and needs to be escaped if you want to match it literally.

(.*?) : match everything in a non-greedy way and capture it.

\] : ] is a meta char and needs to be escaped if you want to match it literally.

Flatten list of lists

Flatten the list to "remove the brackets" using a nested list comprehension. This will un-nest each list stored in your list of lists!

list_of_lists = [[180.0], [173.8], [164.2], [156.5], [147.2], [138.2]]
flattened = [val for sublist in list_of_lists for val in sublist]

Nested list comprehensions evaluate in the same manner that they unwrap (i.e. add newline and tab for each new loop. So in this case:

flattened = [val for sublist in list_of_lists for val in sublist]

is equivalent to:

flattened = []
for sublist in list_of_lists:
    for val in sublist:
        flattened.append(val)

The big difference is that the list comp evaluates MUCH faster than the unraveled loop and eliminates the append calls!

If you have multiple items in a sublist the list comp will even flatten that. ie

>>> list_of_lists = [[180.0, 1, 2, 3], [173.8], [164.2], [156.5], [147.2], [138.2]]
>>> flattened  = [val for sublist in list_of_lists for val in sublist]
>>> flattened 
[180.0, 1, 2, 3, 173.8, 164.2, 156.5, 147.2,138.2]

How to select between brackets (or quotes or ...) in Vim?

I've made a plugin vim-textobj-quotes: https://github.com/beloglazov/vim-textobj-quotes

It provides text objects for the closest pairs of quotes of any type. Using only iq or aq it allows you to operate on the content of single ('), double ("), or back (`) quotes that currently surround the cursor, are in front of the cursor, or behind (in that order of preference). In other words, it jumps forward or backwards when needed to reach the quotes.

It's easier to understand by looking at examples (the cursor is shown with |):

  1. Before: foo '1, |2, 3' bar; after pressing diq: foo '|' bar
  2. Before: foo| '1, 2, 3' bar; after pressing diq: foo '|' bar
  3. Before: foo '1, 2, 3' |bar; after pressing diq: foo '|' bar
  4. Before: foo '1, |2, 3' bar; after pressing daq: foo | bar
  5. Before: foo| '1, 2, 3' bar; after pressing daq: foo | bar
  6. Before: foo '1, 2, 3' |bar; after pressing daq: foo | bar

The examples above are given for single quotes, the plugin works exactly the same way for double (") and back (`) quotes.

You can also use any other operators: ciq, diq, yiq, viq, etc.

Please have a look at the github page linked above for more details.

Error in launching AVD with AMD processor

For AMD processors:

You don't need Genymotion, just create a new Virtual Device and while selecting the system Image select the ABI as armeabi instead of the default x86 one.

enter image description here

Using NULL in C++?

In C++ NULL expands to 0 or 0L. See this quote from Stroustrup's FAQ:

Should I use NULL or 0?

In C++, the definition of NULL is 0, so there is only an aesthetic difference. I prefer to avoid macros, so I use 0. Another problem with NULL is that people sometimes mistakenly believe that it is different from 0 and/or not an integer. In pre-standard code, NULL was/is sometimes defined to something unsuitable and therefore had/has to be avoided. That's less common these days.

If you have to name the null pointer, call it nullptr; that's what it's called in C++11. Then, "nullptr" will be a keyword.

Get Selected Item Using Checkbox in Listview

[Custom ListView with CheckBox]

If customlayout use checkbox, you must set checkbox focusable = false

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">

  <TextView android:id="@+id/rowTextView" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:textSize="16sp" >
  </TextView>

  <CheckBox android:id="@+id/CheckBox01" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:padding="10dp"
    android:layout_alignParentRight="true" 
    android:layout_marginRight="6sp"
    android:focusable="false">           // <---important
  </CheckBox>

</RelativeLayout>

Readmore : A ListView with Checkboxes (Without Using ListActivity)

What is difference between Errors and Exceptions?

Error is something that most of the time you cannot handle it.

Exception was meant to give you an opportunity to do something with it. like try something else or write to the log.

try{
  //connect to database 1
}
catch(DatabaseConnctionException err){
  //connect to database 2
  //write the err to log
}

Pip error: Microsoft Visual C++ 14.0 is required

Pycrypto has vulnerabilities assigned the CVE-2013-7459 number, and the repo hasn't accept PRs since June 23, 2014.

Pycryptodome is a drop-in replacement for the PyCrypto library, which exposes almost the same API as the old PyCrypto, see Compatibility with PyCrypto.

If you haven't install pycrypto yet, you can use pip install pycryptodome to install pycryptodome in which you won't get Microsoft Visual C++ 14.0 issue.

Deleting array elements in JavaScript - delete vs splice

If the desired element to delete is in the middle (say we want to delete 'c', which its index is 1), you can use:

var arr = ['a','b','c'];
var indexToDelete = 1;
var newArray = arr.slice(0,indexToDelete).combine(arr.slice(indexToDelete+1, arr.length))

What's a simple way to get a text input popup dialog box on an iPhone

Swift 3:

let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.default, handler: nil))
alert.addTextField(configurationHandler: {(textField: UITextField!) in
     textField.placeholder = "Enter text:"
})

self.present(alert, animated: true, completion: nil)

org.json.simple cannot be resolved

The jar file is missing. You can download the jar file and add it as external libraries in your project . You can download this from

http://www.findjar.com/jar/com/googlecode/json-simple/json-simple/1.1/json-simple-1.1.jar.html

Installing PHP Zip Extension

On Amazon Linux 2 and PHP 7.4 I finally got PHP-ZIP to install and I hope it helps someone else - by the following (note the yum install command has extra common modules also included you may not need them all):

sudo yum -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

sudo yum -y install https://rpms.remirepo.net/enterprise/remi-release-7.rpm

sudo yum -y install yum-utils

sudo yum-config-manager --enable remi-php74

sudo yum update

sudo yum install php php-cli php-fpm php-mysqlnd php-zip php-devel php-gd php-mcrypt php-mbstring php-curl php-xml php-pear php-bcmath php-json

sudo pecl install zip

php --modules

sudo systemctl restart httpd

bool to int conversion

Section 6.5.8.6 of the C standard says:

Each of the operators < (less than), > (greater than), <= (less than or equal to), and >= (greater than or equal to) shall yield 1 if the specified relation is true and 0 if it is false.) The result has type int.

Creating a directory in /sdcard fails

Isn't it already created ? Mkdir returns false if the folder already exists too mkdir

How to delete object from array inside foreach loop?

foreach($array as $elementKey => $element) {
    foreach($element as $valueKey => $value) {
        if($valueKey == 'id' && $value == 'searched_value'){
            //delete this particular object from the $array
            unset($array[$elementKey]);
        } 
    }
}

Name does not exist in the current context

In our case, beside changing ToolsVersion from 14.0 to 15.0 on .csproj projet file, as stated by Dominik Litschauer, we also had to install an updated version of MSBuild, since compilation is being triggered by a Jenkins job. After installing Build Tools for Visual Studio 2019, we had got MsBuild version 16.0 and all new C# features compiled ok.

node.js shell command execution

@TonyO'Hagan is comprehrensive shelljs answer, but, I would like to highlight the synchronous version of his answer:

var shell = require('shelljs');
var output = shell.exec('netstat -rn', {silent:true}).output;
console.log(output);

How to add Options Menu to Fragment in Android

Menu file:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/play"
        android:titleCondensed="Speak"
        android:showAsAction="always"
        android:title="Speak"
        android:icon="@drawable/ic_play">
    </item>
    <item
        android:id="@+id/pause"
        android:titleCondensed="Stop"
        android:title="Stop"
        android:showAsAction="always"
        android:icon="@drawable/ic_pause">
    </item>
</menu>

Activity code:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.speak_menu_history, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {

        case R.id.play:
            Toast.makeText(getApplicationContext(), "speaking....", Toast.LENGTH_LONG).show();
            return false;

        case R.id.pause:
            Toast.makeText(getApplicationContext(), "stopping....", Toast.LENGTH_LONG).show();
            return false;

        default:
            break;
    }

    return false;
}

Fragment code:

@Override

public void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {

        case R.id.play:
            text = page.getText().toString();
            speakOut(text);

            // Do Activity menu item stuff here
            return true;

        case R.id.pause:
            speakOf();

            // Not implemented here
            return true;

        default:
            break;
    }
    return false;
}

How to mention C:\Program Files in batchfile

I had a similar issue as you, although I was trying to use start to open Chrome and using the file path. I used only start chrome.exe and it opened just fine. You may want to try to do the same with exe file. Using the file path may be unnecessary.

Here are some examples (using the file name you gave in a comment on another answer):

  • Instead of C:\Program^ Files\temp.exe you can try temp.exe.

  • Instead of start C:\Program^ Files\temp.exe you can try start temp.exe

How to make zsh run as a login shell on Mac OS X (in iTerm)?

Have you tried editing the shell entry in account settings.

Go to the Accounts preferences, unlock, and right-click on your user account for the Advanced Settings dialog. Your shell should be /bin/zsh, and you can edit that invocation appropriately (i.e. add the --login argument).

Merge unequal dataframes and replace missing rows with 0

"all" option does not work anymore, The new parameter is;

x = pd.merge(df1, df2, how="outer")

How to do something to each file in a directory with a batch script

I had some malware that marked all files in a directory as hidden/system/readonly. If anyone else finds themselves in this situation, cd into the directory and run for /f "delims=|" %f in ('forfiles') do attrib -s -h -r %f.

FFMPEG mp4 from http live streaming m3u8 file?

Your command is completely incorrect. The output format is not rawvideo and you don't need the bitstream filter h264_mp4toannexb which is used when you want to convert the h264 contained in an mp4 to the Annex B format used by MPEG-TS for example. What you want to use instead is the aac_adtstoasc for the AAC streams.

ffmpeg -i http://.../playlist.m3u8 -c copy -bsf:a aac_adtstoasc output.mp4

How do I measure execution time of a command on the Windows command line?

"Lean and Mean" TIMER with Regional format, 24h and mixed input support
Adapting Aacini's substitution method body, no IF's, just one FOR (my regional fix)

1: File timer.bat placed somewhere in %PATH% or the current dir

@echo off & rem :AveYo: compact timer function with Regional format, 24-hours and mixed input support
if not defined timer_set (if not "%~1"=="" (call set "timer_set=%~1") else set "timer_set=%TIME: =0%") & goto :eof
(if not "%~1"=="" (call set "timer_end=%~1") else set "timer_end=%TIME: =0%") & setlocal EnableDelayedExpansion
for /f "tokens=1-6 delims=0123456789" %%i in ("%timer_end%%timer_set%") do (set CE=%%i&set DE=%%k&set CS=%%l&set DS=%%n)
set "TE=!timer_end:%DE%=%%100)*100+1!"     & set "TS=!timer_set:%DS%=%%100)*100+1!"
set/A "T=((((10!TE:%CE%=%%100)*60+1!%%100)-((((10!TS:%CS%=%%100)*60+1!%%100)" & set/A "T=!T:-=8640000-!"
set/A "cc=T%%100+100,T/=100,ss=T%%60+100,T/=60,mm=T%%60+100,hh=T/60+100"
set "value=!hh:~1!%CE%!mm:~1!%CE%!ss:~1!%DE%!cc:~1!" & if "%~2"=="" echo/!value!
endlocal & set "timer_end=%value%" & set "timer_set=" & goto :eof

Usage:
timer & echo start_cmds & timeout /t 3 & echo end_cmds & timer
timer & timer "23:23:23,00"
timer "23:23:23,00" & timer
timer "13.23.23,00" & timer "03:03:03.00"
timer & timer "0:00:00.00" no & cmd /v:on /c echo until midnight=!timer_end!
Input can now be mixed, for those unlikely, but possible time format changes during execution

2: Function :timer bundled with the batch script (sample usage below):

@echo off
set "TIMER=call :timer" & rem short macro
echo.
echo EXAMPLE:
call :timer
timeout /t 3 >nul & rem Any process here..
call :timer
echo.
echo SHORT MACRO:
%TIMER% & timeout /t 1 & %TIMER% 
echo.
echo TEST INPUT:
set "start=22:04:04.58"
set "end=04.22.44,22"
echo %start% ~ start & echo %end% ~ end
call :timer "%start%"
call :timer "%end%"
echo.
%TIMER% & %TIMER% "00:00:00.00" no 
echo UNTIL MIDNIGHT: %timer_end%
echo.
pause 
exit /b

:: to test it, copy-paste both above and below code sections

rem :AveYo: compact timer function with Regional format, 24-hours and mixed input support 
:timer Usage " call :timer [input - optional] [no - optional]" :i Result printed on second call, saved to timer_end 
if not defined timer_set (if not "%~1"=="" (call set "timer_set=%~1") else set "timer_set=%TIME: =0%") & goto :eof
(if not "%~1"=="" (call set "timer_end=%~1") else set "timer_end=%TIME: =0%") & setlocal EnableDelayedExpansion
for /f "tokens=1-6 delims=0123456789" %%i in ("%timer_end%%timer_set%") do (set CE=%%i&set DE=%%k&set CS=%%l&set DS=%%n)
set "TE=!timer_end:%DE%=%%100)*100+1!"     & set "TS=!timer_set:%DS%=%%100)*100+1!"
set/A "T=((((10!TE:%CE%=%%100)*60+1!%%100)-((((10!TS:%CS%=%%100)*60+1!%%100)" & set/A "T=!T:-=8640000-!"
set/A "cc=T%%100+100,T/=100,ss=T%%60+100,T/=60,mm=T%%60+100,hh=T/60+100"
set "value=!hh:~1!%CE%!mm:~1!%CE%!ss:~1!%DE%!cc:~1!" & if "%~2"=="" echo/!value!
endlocal & set "timer_end=%value%" & set "timer_set=" & goto :eof

CE,DE and CS,DS stand for colon end, dot end and colon set, dot set - used for mixed format support

Getting HTML elements by their attribute names

Just another answer

Array.prototype.filter.call(
    document.getElementsByTagName('span'),
    function(el) {return el.getAttribute('property') == 'v.name';}
);

In future

Array.prototype.filter.call(
    document.getElementsByTagName('span'),
    (el) => el.getAttribute('property') == 'v.name'
)

3rd party edit

Intro

  • The call() method calls a function with a given this value and arguments provided individually.

  • The filter() method creates a new array with all elements that pass the test implemented by the provided function.

Given this html markup

<span property="a">apple - no match</span>
<span property="v:name">onion - match</span>
<span property="b">root - match</span>
<span property="v:name">tomato - match</span>
<br />
<button onclick="findSpan()">find span</button>

you can use this javascript

function findSpan(){

    var spans = document.getElementsByTagName('span');
    var spansV = Array.prototype.filter.call(
         spans,
         function(el) {return el.getAttribute('property') == 'v:name';}
    );
    return spansV;
}

See demo

MySQL compare DATE string with string from DATETIME field

Use the following:

SELECT * FROM `calendar` WHERE DATE(startTime) = '2010-04-29'

Just for reference I have a 2 million record table, I ran a similar query. Salils answer took 4.48 seconds, the above took 2.25 seconds.

So if the table is BIG I would suggest this rather.

MySQL set current date in a DATETIME field on insert

Using Now() is not a good idea. It only save the current time and date. It will not update the the current date and time, when you update your data. If you want to add the time once, The default value =Now() is best option. If you want to use timestamp. and want to update the this value, each time that row is updated. Then, trigger is best option to use.

  1. http://www.mysqltutorial.org/sql-triggers.aspx
  2. http://www.tutorialspoint.com/plsql/plsql_triggers.htm

These two toturial will help to implement the trigger.

Why is String immutable in Java?

If HELLO is your String then you can't change HELLO to HILLO. This property is called immutability property.

You can have multiple pointer String variable to point HELLO String.

But if HELLO is char Array then you can change HELLO to HILLO. Eg,

char[] charArr = 'HELLO';
char[1] = 'I'; //you can do this

Answer:

Programming languages have immutable data variables so that it can be used as keys in key, value pair. String variables are used as keys/indices, so they are immutable.

How to remove decimal part from a number in C#

Use Decimal.Truncate

It removes the fractional part from the decimal.

int i = (int)Decimal.Truncate(12.66m)

Command line input in Python

It is not at all clear what the OP meant (even after some back-and-forth in the comments), but here are two answers to possible interpretations of the question:

For interactive user input (or piped commands or redirected input)

Use raw_input in Python 2.x, and input in Python 3. (These are built in, so you don't need to import anything to use them; you just have to use the right one for your version of python.)

For example:

user_input = raw_input("Some input please: ")

More details can be found here.

So, for example, you might have a script that looks like this

# First, do some work, to show -- as requested -- that
# the user input doesn't need to come first.
from __future__ import print_function
var1 = 'tok'
var2 = 'tik'+var1
print(var1, var2)

# Now ask for input
user_input = raw_input("Some input please: ") # or `input("Some...` in python 3

# Now do something with the above
print(user_input)

If you saved this in foo.py, you could just call the script from the command line, it would print out tok tiktok, then ask you for input. You could enter bar baz (followed by the enter key) and it would print bar baz. Here's what that would look like:

$ python foo.py
tok tiktok
Some input please: bar baz
bar baz

Here, $ represents the command-line prompt (so you don't actually type that), and I hit Enter after typing bar baz when it asked for input.

For command-line arguments

Suppose you have a script named foo.py and want to call it with arguments bar and baz from the command line like

$ foo.py bar baz

(Again, $ represents the command-line prompt.) Then, you can do that with the following in your script:

import sys
arg1 = sys.argv[1]
arg2 = sys.argv[2]

Here, the variable arg1 will contain the string 'bar', and arg2 will contain 'baz'. The object sys.argv is just a list containing everything from the command line. Note that sys.argv[0] is the name of the script. And if, for example, you just want a single list of all the arguments, you would use sys.argv[1:].

Calculating moving average

The slider package can be used for this. It has an interface that has been specifically designed to feel similar to purrr. It accepts any arbitrary function, and can return any type of output. Data frames are even iterated over row wise. The pkgdown site is here.

library(slider)

x <- 1:3

# Mean of the current value + 1 value before it
# returned as a double vector
slide_dbl(x, ~mean(.x, na.rm = TRUE), .before = 1)
#> [1] 1.0 1.5 2.5


df <- data.frame(x = x, y = x)

# Slide row wise over data frames
slide(df, ~.x, .before = 1)
#> [[1]]
#>   x y
#> 1 1 1
#> 
#> [[2]]
#>   x y
#> 1 1 1
#> 2 2 2
#> 
#> [[3]]
#>   x y
#> 1 2 2
#> 2 3 3

The overhead of both slider and data.table's frollapply() should be pretty low (much faster than zoo). frollapply() looks to be a little faster for this simple example here, but note that it only takes numeric input, and the output must be a scalar numeric value. slider functions are completely generic, and you can return any data type.

library(slider)
library(zoo)
library(data.table)

x <- 1:50000 + 0L

bench::mark(
  slider = slide_int(x, function(x) 1L, .before = 5, .complete = TRUE),
  zoo = rollapplyr(x, FUN = function(x) 1L, width = 6, fill = NA),
  datatable = frollapply(x, n = 6, FUN = function(x) 1L),
  iterations = 200
)
#> # A tibble: 3 x 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 slider      19.82ms   26.4ms     38.4    829.8KB     19.0
#> 2 zoo        177.92ms  211.1ms      4.71    17.9MB     24.8
#> 3 datatable    7.78ms   10.9ms     87.9    807.1KB     38.7

iTerm2 keyboard shortcut - split pane navigation

Cmd+opt+?/?/?/? navigate similarly to vim's C-w hjkl.

JPQL SELECT between date statement

Try this query (replace t.eventsDate with e.eventsDate):

SELECT e FROM Events e WHERE e.eventsDate BETWEEN :startDate AND :endDate

Angular 2: 404 error occur when I refresh through the browser

For people reading this that use Angular 2 rc4 or later, it appears LocationStrategy has been moved from router to common. You'll have to import it from there.

Also note the curly brackets around the 'provide' line.

main.ts

// Imports for loading & configuring the in-memory web api
import { XHRBackend } from '@angular/http';

// The usual bootstrapping imports
import { bootstrap }      from '@angular/platform-browser-dynamic';
import { HTTP_PROVIDERS } from '@angular/http';

import { AppComponent }         from './app.component';
import { APP_ROUTER_PROVIDERS } from './app.routes';
import { Location, LocationStrategy, HashLocationStrategy} from '@angular/common';

bootstrap(AppComponent, [
    APP_ROUTER_PROVIDERS,
    HTTP_PROVIDERS,
    {provide: LocationStrategy, useClass: HashLocationStrategy}
]);

Incrementing a variable inside a Bash loop

I had the same $count variable in a while loop getting lost issue.

@fedorqui's answer (and a few others) are accurate answers to the actual question: the sub-shell is indeed the problem.

But it lead me to another issue: I wasn't piping a file content... but the output of a series of pipes & greps...

my erroring sample code:

count=0
cat /etc/hosts | head | while read line; do
  ((count++))
  echo $count $line
done
echo $count

and my fix thanks to the help of this thread and the process substitution:

count=0
while IFS= read -r line; do
  ((count++))
  echo "$count $line"
done < <(cat /etc/hosts | head)
echo "$count"

R adding days to a date

You could also use

library(lubridate)
dmy("1/1/2001") + days(45)

How to select all rows which have same value in some column

You can do this without a JOIN:

SELECT *
FROM (SELECT *,COUNT(*) OVER(PARTITION BY phone_number) as Phone_CT
      FROM YourTable
      )sub
WHERE Phone_CT > 1
ORDER BY phone_number, employee_ids

Demo: SQL Fiddle

jQuery: Change button text on click

its work short code

$('.SeeMore2').click(function(){ var $this = $(this).toggleClass('SeeMore2'); if($(this).hasClass('SeeMore2')) { $(this).text('See More');
} else { $(this).text('See Less'); } });

Remove padding or margins from Google Charts

It's missing in the docs (I'm using version 43), but you can actually use the right and bottom property of the chart area:

var options = {
  chartArea:{
    left:10,
    right:10, // !!! works !!!
    bottom:20,  // !!! works !!!
    top:20,
    width:"100%",
    height:"100%"
  }
};

So it's possible to use full responsive width & height and prevent any axis labels or legends from being cropped.

How can I start InternetExplorerDriver using Selenium WebDriver

To run test cases in IE Browser make sure you have downloaded IE driver and you need to set the property as well.

Below code will help you

// This will set the driver
System.setProperty("webdriver.ie.driver","driver path\\IEDriverServer.exe");

// Initialise browser

WebDriver driver=new InternetExplorerDriver();

You can check IE Browser challenges with Selenium and complete code for more details

Difference between HashSet and HashMap?

HashSet and HashMap both store pairs , the difference lies that in HashMap you can specify a key while in HashSet the key comes from object's hash code

How to create a number picker dialog?

I have made a small demo of NumberPicker. This may not be perfect but you can use and modify the same.

public class MainActivity extends Activity implements NumberPicker.OnValueChangeListener
{
    private static TextView tv;
    static Dialog d ;
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.textView1);
        Button b = (Button) findViewById(R.id.button11);
         b.setOnClickListener(new OnClickListener()
         {

            @Override
            public void onClick(View v) {
                 show();
            }
            });
           }
     @Override
    public void onValueChange(NumberPicker picker, int oldVal, int newVal) {

         Log.i("value is",""+newVal);

     }

    public void show()
    {

         final Dialog d = new Dialog(MainActivity.this);
         d.setTitle("NumberPicker");
         d.setContentView(R.layout.dialog);
         Button b1 = (Button) d.findViewById(R.id.button1);
         Button b2 = (Button) d.findViewById(R.id.button2);
         final NumberPicker np = (NumberPicker) d.findViewById(R.id.numberPicker1);
         np.setMaxValue(100);
         np.setMinValue(0);
         np.setWrapSelectorWheel(false);
         np.setOnValueChangedListener(this);
         b1.setOnClickListener(new OnClickListener()
         {
          @Override
          public void onClick(View v) {
              tv.setText(String.valueOf(np.getValue()));
              d.dismiss();
           }    
          });
         b2.setOnClickListener(new OnClickListener()
         {
          @Override
          public void onClick(View v) {
              d.dismiss();
           }    
          });
       d.show();


    }
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/button11"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:text="Open" />

</RelativeLayout>

dialog.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <NumberPicker
        android:id="@+id/numberPicker1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="64dp" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/numberPicker1"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="98dp"
        android:layout_toRightOf="@+id/numberPicker1"
        android:text="Cancel" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button2"
        android:layout_alignBottom="@+id/button2"
        android:layout_marginRight="16dp"
        android:layout_toLeftOf="@+id/numberPicker1"
        android:text="Set" />

</RelativeLayout>

Edit:

under res/values/dimens.xml

<resources>

    <!-- Default screen margins, per the Android Design guidelines. -->
    <dimen name="activity_horizontal_margin">16dp</dimen>
    <dimen name="activity_vertical_margin">16dp</dimen>

</resources>

Socket.IO - how do I get a list of connected sockets/clients?

Socket.io 1.4

Object.keys(io.sockets.sockets); gives you all the connected sockets.

Socket.io 1.0 As of socket.io 1.0, the actual accepted answer isn't valid anymore. So I made a small function that I use as a temporary fix :

function findClientsSocket(roomId, namespace) {
    var res = []
    // the default namespace is "/"
    , ns = io.of(namespace ||"/");

    if (ns) {
        for (var id in ns.connected) {
            if(roomId) {
                var index = ns.connected[id].rooms.indexOf(roomId);
                if(index !== -1) {
                    res.push(ns.connected[id]);
                }
            } else {
                res.push(ns.connected[id]);
            }
        }
    }
    return res;
}

Api for No namespace becomes

// var clients = io.sockets.clients();
// becomes : 
var clients = findClientsSocket();

// var clients = io.sockets.clients('room');
// all users from room `room`
// becomes
var clients = findClientsSocket('room');

Api for a namespace becomes :

// var clients = io.of('/chat').clients();
// becomes
var clients = findClientsSocket(null, '/chat');

// var clients = io.of('/chat').clients('room');
// all users from room `room`
// becomes
var clients = findClientsSocket('room', '/chat');

Also see this related question, in which I give a function that returns the sockets for a given room.

function findClientsSocketByRoomId(roomId) {
var res = []
, room = io.sockets.adapter.rooms[roomId];
if (room) {
    for (var id in room) {
    res.push(io.sockets.adapter.nsp.connected[id]);
    }
}
return res;
}

Socket.io 0.7

API for no namespace:

var clients = io.sockets.clients();
var clients = io.sockets.clients('room'); // all users from room `room`

For a namespace

var clients = io.of('/chat').clients();
var clients = io.of('/chat').clients('room'); // all users from room `room`

Note: Since it seems the socket.io API is prone to breaking, and some solution rely on implementation details, it could be a matter of tracking the clients yourself:

var clients = [];

io.sockets.on('connect', function(client) {
    clients.push(client); 

    client.on('disconnect', function() {
        clients.splice(clients.indexOf(client), 1);
    });
});

JavaScript equivalent of PHP’s die

use firebug and the glorious...

debugger;

and never let the debugger make any step forward. Cleaner than throwing a proper Error, innit?

Performing Breadth First Search recursively

I have made a program using c++ which is working in joint and disjoint graph too .

    #include <queue>
#include "iostream"
#include "vector"
#include "queue"

using namespace std;

struct Edge {
    int source,destination;
};

class Graph{
    int V;
    vector<vector<int>> adjList;
public:

    Graph(vector<Edge> edges,int V){
        this->V = V;
        adjList.resize(V);
        for(auto i : edges){
            adjList[i.source].push_back(i.destination);
            //     adjList[i.destination].push_back(i.source);
        }
    }
    void BFSRecursivelyJoinandDisjointtGraphUtil(vector<bool> &discovered, queue<int> &q);
    void BFSRecursivelyJointandDisjointGraph(int s);
    void printGraph();


};

void Graph :: printGraph()
{
    for (int i = 0; i < this->adjList.size(); i++)
    {
        cout << i << " -- ";
        for (int v : this->adjList[i])
            cout <<"->"<< v << " ";
        cout << endl;
    }
}


void Graph ::BFSRecursivelyJoinandDisjointtGraphUtil(vector<bool> &discovered, queue<int> &q) {
    if (q.empty())
        return;
    int v = q.front();
    q.pop();
    cout << v <<" ";
    for (int u : this->adjList[v])
    {
        if (!discovered[u])
        {
            discovered[u] = true;
            q.push(u);
        }
    }
    BFSRecursivelyJoinandDisjointtGraphUtil(discovered, q);

}

void Graph ::BFSRecursivelyJointandDisjointGraph(int s) {
    vector<bool> discovered(V, false);
    queue<int> q;

    for (int i = s; i < V; i++) {
        if (discovered[i] == false)
        {
            discovered[i] = true;
            q.push(i);
            BFSRecursivelyJoinandDisjointtGraphUtil(discovered, q);
        }
    }
}

int main()
{

    vector<Edge> edges =
            {
                    {0, 1}, {0, 2}, {1, 2}, {2, 0}, {2,3},{3,3}
            };

    int V = 4;
    Graph graph(edges, V);
 //   graph.printGraph();
    graph.BFSRecursivelyJointandDisjointGraph(2);
    cout << "\n";




    edges = {
            {0,4},{1,2},{1,3},{1,4},{2,3},{3,4}
    };

    Graph graph2(edges,5);

    graph2.BFSRecursivelyJointandDisjointGraph(0);
    return 0;
}

How to make a browser display a "save as dialog" so the user can save the content of a string to a file on his system?

There is a new spec called the Native File System API that allows you to do this properly like this:

const result = await window.chooseFileSystemEntries({ type: "save-file" });

There is a demo here, but I believe it is using an origin trial so it may not work in your own website unless you sign up or enable a config flag, and it obviously only works in Chrome. If you're making an Electron app this might be an option though.

How to create a pivot query in sql server without aggregate function

Check this out as well: using xml path and pivot

SQLFIDDLE DEMO

| ACCOUNT | 2000 | 2001 | 2002 |
--------------------------------
|   Asset |  205 |  142 |  421 |
|  Equity |  365 |  214 |  163 |
|  Profit |  524 |  421 |  325 |

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

SET @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.period) 
            FROM demo c
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT account, ' + @cols + ' from 
            (
                select account
                    , value
                    , period
                from demo
           ) x
            pivot 
            (
                 max(value)
                for period in (' + @cols + ')
            ) p '


execute(@query)

Showing which files have changed between two revisions

Try

$ git diff --stat --color master..branchName

This will give you more info about each change, while still using the same number of lines.

You can also flip the branches to get an even clearer picture of the difference if you were to merge the other way:

$ git diff --stat --color branchName..master

Change app language programmatically in Android

This code really works:

fa = Persian, en = English

Enter your language code in languageToLoad variable:

import android.app.Activity;
import android.content.res.Configuration;
import android.os.Bundle;

public class Main extends Activity {
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    String languageToLoad  = "fa"; // your language
    Locale locale = new Locale(languageToLoad); 
    Locale.setDefault(locale);
    Configuration config = new Configuration();
    config.locale = locale;
    getBaseContext().getResources().updateConfiguration(config, 
      getBaseContext().getResources().getDisplayMetrics());
    this.setContentView(R.layout.main);
  }
}

Cannot use a CONTAINS or FREETEXT predicate on table or indexed view because it is not full-text indexed

A workaround for CONTAINS: If you don't want to create a full text Index on the column, and performance is not one of your priorities you could use the LIKE statement which doesn't need any prior configuration:

Example: find all Products that contains the letter Q:

SELECT ID, ProductName
FROM [ProductsDB].[dbo].[Products]
WHERE [ProductsDB].[dbo].[Products].ProductName LIKE '%Q%'

java.lang.NoClassDefFoundError: org/json/JSONObject

Please add the following dependency http://mvnrepository.com/artifact/org.json/json/20080701

<dependency>
   <groupId>org.json</groupId>
   <artifactId>json</artifactId>
   <version>20080701</version>
</dependency>

How to fix Error: listen EADDRINUSE while using nodejs?

For other people on windows 10 with node as localhost and running on a port like 3500, not 80 ...

What does not work:

killall    ?  command not found
ps -aux | grep 'node'     ?     ps:  user x unknown 

What shows information but still not does work:

 ps -aef | grep 'node'
 ps ax
 kill -9 61864

What does work:

Git Bash or Powershell on Windows

  net -a -o | grep 3500   (whatever port you are looking for) 

Notice the PID ( far right )
I could not get killall to work... so

  1. Open your task manager
  2. On processes tab , right click on Name or any column and select to include PID
  3. Sort by PID, then right click on right PID and click end task.

Now after that not so fun exercise on windows, I realized I can use task manager and find the Node engine and just end it.

FYI , I was using Visual Studio Code to run Node on port 3500, and I use Git Bash shell inside VS code. I had exited gracefully with Ctrl + C , but sometimes this does not kill it. I don't want to change my port or reboot so this worked. Hopefully it helps others. Otherwise it is documentation for myself.

Is it possible to cast a Stream in Java 8?

Late to the party, but I think it is a useful answer.

flatMap would be the shortest way to do it.

Stream.of(objects).flatMap(o->(o instanceof Client)?Stream.of((Client)o):Stream.empty())

If o is a Client then create a Stream with a single element, otherwise use the empty stream. These streams will then be flattened into a Stream<Client>.

SQL to generate a list of numbers from 1 to 100

Another interesting solution in ORACLE PL/SQL:

    SELECT LEVEL n
      FROM DUAL
CONNECT BY LEVEL <= 100;

Sites not accepting wget user agent header

You need to set both the user-agent and the referer:

 wget  --header="Accept: text/html" --user-agent="Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:21.0) Gecko/20100101 Firefox/21.0" --referrer  connect.wso2.com http://dist.wso2.org/products/carbon/4.2.0/wso2carbon-4.2.0.zip

How to get a value from a Pandas DataFrame and not the index and object type

Nobody mentioned it, but you can also simply use loc with the index and column labels.

df.loc[2, 'Letters']
# 'C'

Or, if you prefer to use "Numbers" column as reference, you can also set is as an index.

df.set_index('Numbers').loc[3, 'Letters']

Get user's current location

MaxMind GeoIP is a good service. They also have a free city-level lookup service.

Get Bitmap attached to ImageView

try this code:

Bitmap bitmap;
bitmap = ((BitmapDrawable)image.getDrawable()).getBitmap();

How to set RelativeLayout layout params in code not in xml?

How about you just pull the layout params from the view itself if you created it.

$((RelativeLayout)findViewById(R.id.imageButton1)).getLayoutParams();

Current timestamp as filename in Java

No need to get too complicated, try this one liner:

String fileName = new SimpleDateFormat("yyyyMMddHHmm'.txt'").format(new Date());

mysqli_real_connect(): (HY000/2002): No such file or directory

If above solutions doesn't work, try to change the default por from 3306, to another one (i.e. 3307)

Find all zero-byte files in directory and subdirectories

No, you don't have to bother grep.

find $dir -size 0 ! -name "*.xml"

perform an action on checkbox checked or unchecked event on html form

Given you use JQuery, you can do something like below :

HTML

<form id="myform">
    syn<input type="checkbox" name="checkfield" id="g01-01"  onclick="doalert()"/>
</form>

JS

function doalert() {
  if ($("#g01-01").is(":checked")) {
    alert ("hi");
  } else {
    alert ("bye");
  }
}

An internal error occurred during: "Updating Maven Project". java.lang.NullPointerException

I had to reinstall eclipse, delete .m2 folder and rebuild the jars.

How do you set the startup page for debugging in an ASP.NET MVC application?

Go to your project's properties and set the start page property.

  1. Go to the project's Properties
  2. Go to the Web tab
  3. Select the Specific Page radio button
  4. Type in the desired url in the Specific Page text box

INSERT INTO a temp table, and have an IDENTITY field created, without first declaring the temp table?

You commented: not working if oldtable has an identity column.

I think that's your answer. The #newtable gets an identity column from the oldtable automatically. Run the next statements:

create table oldtable (id int not null identity(1,1), v varchar(10) )

select * into #newtable from oldtable

use tempdb
GO
sp_help #newtable

It shows you that #newtable does have the identity column.

If you don't want the identity column, try this at creation of #newtable:

select id + 1 - 1 as nid, v, IDENTITY( int ) as id into #newtable
     from oldtable

Can ordered list produce result that looks like 1.1, 1.2, 1.3 (instead of just 1, 2, 3, ...) with css?

The solutions posted here did not work well for me, so I did a mixture of the ones of this question and the following question: Is it possible to create multi-level ordered list in HTML?

/* Numbered lists like 1, 1.1, 2.2.1... */
ol li {display:block;} /* hide original list counter */
ol > li:first-child {counter-reset: item;} /* reset counter */
ol > li {counter-increment: item; position: relative;} /* increment counter */
ol > li:before {content:counters(item, ".") ". "; position: absolute; margin-right: 100%; right: 10px;} /* print counter */

Result:

screenshot

Note: the screenshot, if you wish to see the source code or whatever is from this post: http://estiloasertivo.blogspot.com.es/2014/08/introduccion-running-lean-y-lean.html

jQuery datepicker to prevent past date

This should work <input type="text" id="datepicker">

var dateToday = new Date();
$("#datepicker").datepicker({
    minDate: dateToday,
    onSelect: function(selectedDate) {
    var option = this.id == "datepicker" ? "minDate" : "maxDate",
    instance = $(this).data("datepicker"),
    date = $.datepicker.parseDate(instance.settings.dateFormat || $.datepicker._defaults.dateFormat, selectedDate, instance.settings);
    dates.not(this).datepicker("option", option, date);
    }
});

What is the final version of the ADT Bundle?

You can also get an updated version of the Eclipse's ADT plugin (based on an unreleased 24.2.0 version) that I managed to patch and compile at https://github.com/khaledev/ADT.

Sending data through POST request from a node.js server to a node.js server

Posting data is a matter of sending a query string (just like the way you would send it with an URL after the ?) as the request body.

This requires Content-Type and Content-Length headers, so the receiving server knows how to interpret the incoming data. (*)

var querystring = require('querystring');
var http = require('http');

var data = querystring.stringify({
      username: yourUsernameValue,
      password: yourPasswordValue
    });

var options = {
    host: 'my.url',
    port: 80,
    path: '/login',
    method: 'POST',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Content-Length': Buffer.byteLength(data)
    }
};

var req = http.request(options, function(res) {
    res.setEncoding('utf8');
    res.on('data', function (chunk) {
        console.log("body: " + chunk);
    });
});

req.write(data);
req.end();

(*) Sending data requires the Content-Type header to be set correctly, i.e. application/x-www-form-urlencoded for the traditional format that a standard HTML form would use.

It's easy to send JSON (application/json) in exactly the same manner; just JSON.stringify() the data beforehand.

URL-encoded data supports one level of structure (i.e. key and value). JSON is useful when it comes to exchanging data that has a nested structure.

The bottom line is: The server must be able to interpret the content type in question. It could be text/plain or anything else; there is no need to convert data if the receiving server understands it as it is.

Add a charset parameter (e.g. application/json; charset=Windows-1252) if your data is in an unusual character set, i.e. not UTF-8. This can be necessary if you read it from a file, for example.

Browse and display files in a git repo without cloning

Take a look at http://git-scm.com/book/en/Git-Internals-Transfer-Protocols for info on how to do this over some transport protocols. Note this won't work for standard git over SSH.

For git over SSH, an up-to-date server-side git should allow you to git-archive directly from the remote, which you could then e.g. pipe to "tar t" to get a list of all files in a given commit.

Reset textbox value in javascript

With jQuery, I've found that sometimes using val to clear the value of a textbox has no effect, in those situations I've found that using attr does the job

$('#searchField').attr("value", "");

Complex numbers usage in python

The following example for complex numbers should be self explanatory including the error message at the end

>>> x=complex(1,2)
>>> print x
(1+2j)
>>> y=complex(3,4)
>>> print y
(3+4j)
>>> z=x+y
>>> print x
(1+2j)
>>> print z
(4+6j)
>>> z=x*y
>>> print z
(-5+10j)
>>> z=x/y
>>> print z
(0.44+0.08j)
>>> print x.conjugate()
(1-2j)
>>> print x.imag
2.0
>>> print x.real
1.0
>>> print x>y

Traceback (most recent call last):
  File "<pyshell#149>", line 1, in <module>
    print x>y
TypeError: no ordering relation is defined for complex numbers
>>> print x==y
False
>>> 

Change a Django form field to a hidden field

an option that worked for me, define the field in the original form as:

forms.CharField(widget = forms.HiddenInput(), required = False)

then when you override it in the new Class it will keep it's place.

PHP Array to JSON Array using json_encode();

If the array keys in your PHP array are not consecutive numbers, json_encode() must make the other construct an object since JavaScript arrays are always consecutively numerically indexed.

Use array_values() on the outer structure in PHP to discard the original array keys and replace them with zero-based consecutive numbering:

Example:

// Non-consecutive 3number keys are OK for PHP
// but not for a JavaScript array
$array = array(
  2 => array("Afghanistan", 32, 13),
  4 => array("Albania", 32, 12)
);

// array_values() removes the original keys and replaces
// with plain consecutive numbers
$out = array_values($array);
json_encode($out);
// [["Afghanistan", 32, 13], ["Albania", 32, 12]]

HTML form submit to PHP script

Try this:

<form method="post" action="check.php">
    <select name="website_string">
        <option value="" selected="selected"></option>
        <option VALUE="abc"> ABC</option>
        <option VALUE="def"> def</option>
        <option VALUE="hij"> hij</option>
    </select>
    <input TYPE="submit" name="submit" />
</form>

Both your select control and your submit button had the same name attribute, so the last one used was the submit button when you clicked it. All other syntax errors aside.

check.php

<?php
    echo $_POST['website_string'];
?>

Obligatory disclaimer about using raw $_POST data. Sanitize anything you'll actually be using in application logic.

How to create a RelativeLayout programmatically with two buttons one on top of the other?

public class AndroidWalkthroughApp1 extends Activity implements View.OnClickListener {

    final int TOP_ID = 3;
    final int BOTTOM_ID = 4;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // create two layouts to hold buttons
        RelativeLayout top = new RelativeLayout(this);
        top.setId(TOP_ID);
        RelativeLayout bottom = new RelativeLayout(this);
        bottom.setId(BOTTOM_ID);

        // create buttons in a loop
        for (int i = 0; i < 2; i++) {
            Button button = new Button(this);
            button.setText("Button " + i);
            // R.id won't be generated for us, so we need to create one
            button.setId(i);

            // add our event handler (less memory than an anonymous inner class)
            button.setOnClickListener(this);

            // add generated button to view
            if (i == 0) {
                top.addView(button);
            }
            else {
                bottom.addView(button);
            }
        }

        RelativeLayout root = (RelativeLayout) findViewById(R.id.root_layout);

        // add generated layouts to root layout view
       // LinearLayout root = (LinearLayout)this.findViewById(R.id.root_layout);

        root.addView(top);
        root.addView(bottom);
    }

    @Override
    public void onClick(View v) {
        // show a message with the button's ID
        Toast toast = Toast.makeText(AndroidWalkthroughApp1.this, "You clicked button " + v.getId(), Toast.LENGTH_LONG);
        toast.show();

        // get the parent layout and remove the clicked button
        RelativeLayout parentLayout = (RelativeLayout)v.getParent();
        parentLayout.removeView(v);



    }
}

Why are only a few video games written in Java?

  1. Java is slow, most of the heavy lifting is not handled by the GPU. There's still animation, physics, and AI hitting the CPU, all of which are very time-consuming.

  2. Java doesn't exist on consoles, and consoles are a major target for commercial games. If you use Java on PC, you're eliminating your ability to port to consoles within reasonable time and budget.

  3. Many of the more experienced coders in the game industry have been using C and C++ long before Java became popular. The two points above may contribute to this, but I expect that many professional game coders just don't really know Java all that well.

  4. Someone else's point about middleware above was a good one, so I'm adding it to my answer. There's a lot of legacy code and middleware written specifically to link with C/C++, and last I checked Java doesn't have good interoperability. Using Java for most companies would involve throwing out a lot of code, much of which has been paid for in one way or another.

Disable eslint rules for folder

To ignore some folder from eslint rules we could create the file .eslintignore in root directory and add there the path to the folder we want omit (the same way as for .gitignore).

Here is the example from the ESLint docs on Ignoring Files and Directories:

# path/to/project/root/.eslintignore
# /node_modules/* and /bower_components/* in the project root are ignored by default

# Ignore built files except build/index.js
build/*
!build/index.js

How to increase executionTimeout for a long-running query?

When a query takes that long, I would advice to run it asynchronously and use a callback function for when it's complete.

I don't have much experience with ASP.NET, but maybe you can use AJAX for this asynchronous behavior.

Typically a web page should load in mere seconds, not minutes. Don't keep your users waiting for so long!

Any way to Invoke a private method?

Use getDeclaredMethod() to get a private Method object and then use method.setAccessible() to allow to actually call it.

How to import jquery using ES6 syntax?

I did not see this exact syntax posted yet, and it worked for me in an ES6/Webpack environment:

import $ from "jquery";

Taken directly from jQuery's NPM page. Hope this helps someone.

Java ArrayList replace at specific index

Use the set() method: see doc

arraylist.set(index,newvalue);

Size-limited queue that holds last N elements in Java

Use composition not extends (yes I mean extends, as in a reference to the extends keyword in java and yes this is inheritance). Composition is superier because it completely shields your implementation, allowing you to change the implementation without impacting the users of your class.

I recommend trying something like this (I'm typing directly into this window, so buyer beware of syntax errors):

public LimitedSizeQueue implements Queue
{
  private int maxSize;
  private LinkedList storageArea;

  public LimitedSizeQueue(final int maxSize)
  {
    this.maxSize = maxSize;
    storageArea = new LinkedList();
  }

  public boolean offer(ElementType element)
  {
    if (storageArea.size() < maxSize)
    {
      storageArea.addFirst(element);
    }
    else
    {
      ... remove last element;
      storageArea.addFirst(element);
    }
  }

  ... the rest of this class

A better option (based on the answer by Asaf) might be to wrap the Apache Collections CircularFifoBuffer with a generic class. For example:

public LimitedSizeQueue<ElementType> implements Queue<ElementType>
{
    private int maxSize;
    private CircularFifoBuffer storageArea;

    public LimitedSizeQueue(final int maxSize)
    {
        if (maxSize > 0)
        {
            this.maxSize = maxSize;
            storateArea = new CircularFifoBuffer(maxSize);
        }
        else
        {
            throw new IllegalArgumentException("blah blah blah");
        }
    }

    ... implement the Queue interface using the CircularFifoBuffer class
}

Cannot assign requested address - possible causes?

It turns out that the problem really was that the address was busy - the busyness was caused by some other problems in how we are handling network communications. Your inputs have helped me figure this out. Thank you.

EDIT: to be specific, the problems in handling our network communications were that these status updates would be constantly re-sent if the first failed. It was only a matter of time until we had every distributed slave trying to send its status update at the same time, which was over-saturating our network.

Checking if a variable is an integer

You can use the is_a? method

>> 1.is_a? Integer
=> true
>> "[email protected]".is_a? Integer
=> false
>> nil.is_a? Integer
=> false

Why is semicolon allowed in this python snippet?

Multiple statements on one line may include semicolons as separators. For example: http://docs.python.org/reference/compound_stmts.html In your case, it makes for an easy insertion of a point to break into the debugger.

Also, as mentioned by Mark Lutz in the Learning Python Book, it is technically legal (although unnecessary and annoying) to terminate all your statements with semicolons.

kubectl apply vs kubectl create?

+----------------------------------------------------------+
¦ command ¦ object does not exist ¦ object already exists  ¦
+---------+-----------------------+------------------------¦
¦ create  ¦ create new object     ¦          ERROR         ¦ 
¦         ¦                       ¦                        ¦
¦ apply   ¦ create new object     ¦ configure object       ¦
¦         ¦ (needs complete spec) ¦ (accepts partial spec) ¦
¦         ¦                       ¦                        ¦
¦ replace ¦         ERROR         ¦ delete object          ¦
¦         ¦                       ¦ create new object      ¦
+----------------------------------------------------------+

Check if starting characters of a string are alphabetical in T-SQL

select * from my_table where my_field Like '[a-z][a-z]%'

overlay a smaller image on a larger image python OpenCv

When attempting to write to the destination image using any of these answers above and you get the following error:

ValueError: assignment destination is read-only

A quick potential fix is to set the WRITEABLE flag to true.

img.setflags(write=1)

How to redirect to Index from another controller?

Complete answer (.Net Core 3.1)

Most answers here are correct but taken a bit out of context, so I will provide a full-fledged answer which works for Asp.Net Core 3.1. For completeness' sake:

[Route("health")]
[ApiController]
public class HealthController : Controller
{
    [HttpGet("some_health_url")]
    public ActionResult SomeHealthMethod() {}
}

[Route("v2")]
[ApiController]
public class V2Controller : Controller
{
    [HttpGet("some_url")]
    public ActionResult SomeV2Method()
    {
        return RedirectToAction("SomeHealthMethod", "Health"); // omit "Controller"
    }
}

If you try to use any of the url-specific strings, e.g. "some_health_url", it will not work!

Most efficient conversion of ResultSet to JSON?

For all who've opted for the if-else mesh solution, please use:

String columnName = metadata.getColumnName(
String displayName = metadata.getColumnLabel(i);
switch (metadata.getColumnType(i)) {
case Types.ARRAY:
    obj.put(displayName, resultSet.getArray(columnName));
    break;
...

Because in case of aliases in your query, the column name and column label are two different things. For example if you execute:

select col1, col2 as my_alias from table

You will get

[
    { "col1": 1, "col2": 2 }, 
    { "col1": 1, "col2": 2 }
]

Rather than:

[
    { "col1": 1, "my_alias": 2 }, 
    { "col1": 1, "my_alias": 2 }
]

CSS Outside Border

Try the outline property W3Schools - CSS Outline

Outline will not interfere with widths and lenghts of the elements/divs!

Please click the link I provided at the bottom to see working demos of the the different ways you can make borders, and inner/inline borders, even ones that do not disrupt the dimensions of the element! No need to add extra divs every time, as mentioned in another answer!

You can also combine borders with outlines, and if you like, box-shadows (also shown via link)

<head>
   <style type="text/css" ref="stylesheet">
      div {
        width:22px;
        height:22px;
        outline:1px solid black;
      }
   </style>
</head>
<div>
    outlined
</div>

Usually by default, 'border:' puts the border on the outside of the width, measurement, adding to the overall dimensions, unless you use the 'inset' value:

div {border: inset solid 1px black};

But 'outline:' is an extra border outside of the border, and of course still adds extra width/length to the element.

Hope this helps

PS: I also was inspired to make this for you : Using borders, outlines, and box-shadows

Bash: If/Else statement in one line

Use grep -vc to ignore grep in the ps output and count the lines simultaneously.

if [[ $(ps aux | grep process | grep -vc grep)  > 0 ]] ; then echo 1; else echo 0 ; fi

How to use split?

If it is the basic JavaScript split function, look at documentation, JavaScript split() Method.

Basically, you just do this:

var array = myString.split(' -- ')

Then your two values are stored in the array - you can get the values like this:

var firstValue = array[0];
var secondValue = array[1];

What does the arrow operator, '->', do in Java?

New Operator for lambda expression added in java 8

Lambda expression is the short way of method writing.
It is indirectly used to implement functional interface

Primary Syntax : (parameters) -> { statements; }

There are some basic rules for effective lambda expressions writting which you should konw.

How to get table list in database, using MS SQL 2008?

This query will get you all the tables in the database

USE [DatabaseName];

SELECT * FROM information_schema.tables;

How to run a specific Android app using Terminal?

Use the cmd activity start-activity (or the alternative am start) command, which is a command-line interface to the ActivityManager. Use am to start activities as shown in this help:

$ adb shell am
usage: am [start|instrument]
       am start [-a <ACTION>] [-d <DATA_URI>] [-t <MIME_TYPE>]
                [-c <CATEGORY> [-c <CATEGORY>] ...]
                [-e <EXTRA_KEY> <EXTRA_VALUE> [-e <EXTRA_KEY> <EXTRA_VALUE> ...]
                [-n <COMPONENT>] [-D] [<URI>]
       ...

For example, to start the Contacts application, and supposing you know only the package name but not the Activity, you can use

$ pkg=com.google.android.contacts
$ comp=$(adb shell cmd package resolve-activity --brief -c android.intent.category.LAUNCHER $pkg | tail -1)
$ adb shell cmd activity start-activity $comp

or the alternative

$ adb shell am start -n $comp

See also http://www.kandroid.org/online-pdk/guide/instrumentation_testing.html (may be a copy of obsolete url : http://source.android.com/porting/instrumentation_testing.html ) for other details.

To terminate the application you can use

$ adb shell am kill com.google.android.contacts

or the more drastic

$ adb shell am force-stop com.google.android.contacts

How to Import 1GB .sql file to WAMP/phpmyadmin

A phpMyAdmin feature called UploadDir permits to upload your file via another mechanism, then importing it from the server's file system. See http://docs.phpmyadmin.net/en/latest/faq.html#i-cannot-upload-big-dump-files-memory-http-or-timeout-problems.

Displaying a Table in Django from Database

The easiest way is to use a for loop template tag.

Given the view:

def MyView(request):
    ...
    query_results = YourModel.objects.all()
    ...
    #return a response to your template and add query_results to the context

You can add a snippet like this your template...

<table>
    <tr>
        <th>Field 1</th>
        ...
        <th>Field N</th>
    </tr>
    {% for item in query_results %}
    <tr> 
        <td>{{ item.field1 }}</td>
        ...
        <td>{{ item.fieldN }}</td>
    </tr>
    {% endfor %}
</table>

This is all covered in Part 3 of the Django tutorial. And here's Part 1 if you need to start there.

See full command of running/stopped container in Docker

TL-DR

docker ps --no-trunc and docker inspect CONTAINER provide the entrypoint executed to start the container, along the command passed to, but that may miss some parts such as ${ANY_VAR} because container environment variables are not printed as resolved.

To overcome that, docker inspect CONTAINER has an advantage because it also allow to retrieve separately env variables and their values defined in the container from the Config.Env property.

docker ps and docker inspect provide information about the executed entrypoint and its command. Often, that is a wrapper entrypoint script (.sh) and not the "real" program started by the container. To get information on that, requesting process information with ps or /proc/1/cmdline help.


1) docker ps --no-trunc

It prints the entrypoint and the command executed for all running containers. While it prints the command passed to the entrypoint (if we pass that), it doesn't show value of docker env variables (such as $FOO or ${FOO}).
If our containers use env variables, it may be not enough.

For example, run an alpine container :

docker run --name alpine-example -e MY_VAR=/var alpine:latest sh -c 'ls $MY_VAR'

When use docker -ps such as :

docker ps -a --filter name=alpine-example --no-trunc

It prints :

CONTAINER ID           IMAGE               COMMAND                CREATED             STATUS                     PORTS               NAMES
5b064a6de6d8417...   alpine:latest       "sh -c 'ls $MY_VAR'"   2 minutes ago       Exited (0) 2 minutes ago                       alpine-example

We see the command passed to the entrypoint : sh -c 'ls $MY_VAR' but $MY_VAR is indeed not resolved.

2) docker inspect CONTAINER

When we inspect the alpine-example container :

docker inspect alpine-example | grep -4 Cmd

The command is also there but we don't still see the env variable value :

        "Cmd": [
            "sh",
            "-c",
            "ls $MY_VAR"
        ],

In fact, we could not see interpolated variables with these docker commands.
While as a trade-off, we could display separately both command and env variables for a container with docker inspect :

docker inspect  alpine-example  | grep -4 -E "Cmd|Env"

That prints :

        "Env": [
            "MY_VAR=/var",
            "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
        ],
        "Cmd": [
            "sh",
            "-c",
            "ls $MY_VAR"
        ]

A more docker way would be to use the --format flag of docker inspect that allows to specify JSON attributes to render :

docker inspect --format '{{.Name}} {{.Config.Cmd}}  {{ (.Config.Env) }}'  alpine-example

That outputs :

/alpine-example [sh -c ls $MY_VAR]  [MY_VAR=/var PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin]

3) Retrieve the started process from the container itself for running containers

The entrypoint and command executed by docker may be helpful but in some cases, it is not enough because that is "only" a wrapper entrypoint script (.sh) that is responsible to start the real/core process.
For example when I run a Nexus container, the command executed and shown to run the container is "sh -c ${SONATYPE_DIR}/start-nexus-repository-manager.sh".
For PostgreSQL that is "docker-entrypoint.sh postgres".

To get more information, we could execute on a running container docker exec CONTAINER ps aux.
It may print other processes that may not interest us.
To narrow to the initial process launched by the entrypoint, we could do :

docker exec CONTAINER ps -1

I specify 1 because the process executed by the entrypoint is generally the one with the 1 id.

Without ps, we could still find the information in /proc/1/cmdline (in most of Linux distros but not all). For example :

docker exec CONTAINER cat /proc/1/cmdline | sed -e "s/\x00/ /g"; echo    

If we have access to the docker host that started the container, another alternative to get the full command of the process executed by the entrypoint is : : execute ps -PID where PID is the local process created by the Docker daemon to run the container such as :

ps -$(docker container inspect --format '{{.State.Pid}}'  CONTAINER)

User-friendly formatting with docker ps

docker ps --no-trunc is not always easy to read.
Specifying columns to print and in a tabular format may make it better :

docker ps   --no-trunc  --format "table{{.Names}}\t{{.CreatedAt}}\t{{.Command}}"

Create an alias may help :

alias dps='docker ps   --no-trunc  --format "table{{.Names}}\t{{.CreatedAt}}\t{{.Command}}"'

jQuery Array of all selected checkboxes (by class)

You can also add underscore.js to your project and will be able to do it in one line:

_.map($("input[name='category_ids[]']:checked"), function(el){return $(el).val()})

Adding an arbitrary line to a matplotlib plot in ipython notebook

Matplolib now allows for 'annotation lines' as the OP was seeking. The annotate() function allows several forms of connecting paths and a headless and tailess arrow, i.e., a simple line, is one of them.

ax.annotate("",
            xy=(0.2, 0.2), xycoords='data',
            xytext=(0.8, 0.8), textcoords='data',
            arrowprops=dict(arrowstyle="-",
                      connectionstyle="arc3, rad=0"),
            )

In the documentation it says you can draw only an arrow with an empty string as the first argument.

From the OP's example:

%matplotlib notebook
import numpy as np
import matplotlib.pyplot as plt

np.random.seed(5)
x = np.arange(1, 101)
y = 20 + 3 * x + np.random.normal(0, 60, 100)
plt.plot(x, y, "o")


# draw vertical line from (70,100) to (70, 250)
plt.annotate("",
              xy=(70, 100), xycoords='data',
              xytext=(70, 250), textcoords='data',
              arrowprops=dict(arrowstyle="-",
                              connectionstyle="arc3,rad=0."), 
              )

# draw diagonal line from (70, 90) to (90, 200)
plt.annotate("",
              xy=(70, 90), xycoords='data',
              xytext=(90, 200), textcoords='data',
              arrowprops=dict(arrowstyle="-",
                              connectionstyle="arc3,rad=0."), 
              )

plt.show()

Example inline image

Just as in the approach in gcalmettes's answer, you can choose the color, line width, line style, etc..

Here is an alteration to a portion of the code that would make one of the two example lines red, wider, and not 100% opaque.

# draw vertical line from (70,100) to (70, 250)
plt.annotate("",
              xy=(70, 100), xycoords='data',
              xytext=(70, 250), textcoords='data',
              arrowprops=dict(arrowstyle="-",
                              edgecolor = "red",
                              linewidth=5,
                              alpha=0.65,
                              connectionstyle="arc3,rad=0."), 
              )

You can also add curve to the connecting line by adjusting the connectionstyle.

Is it possible to append Series to rows of DataFrame without making a list first?

Try using this command. See the example given below:

Before image

df.loc[len(df)] = ['Product 9',99,9.99,8.88,1.11]

df

After Image

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.

Preventing form resubmission

You can use replaceState method of JQuery:

<script>
   $(document).ready(function(){
   window.history.replaceState('','',window.location.href)
   });
</script>

This is the most elegant way to prevent data again after submission due to post back.

Hope this helps.

Is there a shortcut to make a block comment in Xcode?

If you're looking a way to convert autogenerated comment from Add Documentation action (available under cmd-shift-/) you might find it useful too:

function run(input, parameters) {
  var lines = input[0].split('\n');
  var line1 = lines[0];
  var prefixRe = /^( *)\/\/\/?(.*)/gm;
  var prefix = prefixRe.test(line1) ? line1.replace(prefixRe, "$1") : ""

  var result = prefix + "/*\n";  
  lines.forEach(function(line) {
    result += prefix + line.replace(prefixRe, "$2") + '\n';
  });
  result += '\n' + prefix + ' */';
  return result;
}

Rest the same as in @Charles Robertson answer:

Automator

Services

Installing PIL with pip

You should install as described here:

pip install image

What is HEAD in Git?

It feels like that HEAD is just a tag for the last commit that you checked out.

This can be the tip of a specific branch (such as "master") or some in-between commit of a branch ("detached head")

unix sort descending order

The presence of the n option attached to the -k5 causes the global -r option to be ignored for that field. You have to specify both n and r at the same level (globally or locally).

sort -t $'\t' -k5,5rn

or

sort -rn -t $'\t' -k5,5

Should try...catch go inside or outside a loop?

setting up a special stack frame for the try/catch adds additional overhead, but the JVM may be able to detect the fact that you're returning and optimize this away.

depending on the number of iterations, performance difference will likely be negligible.

However i agree with the others that having it outside the loop make the loop body look cleaner.

If there's a chance that you'll ever want to continue on with the processing rather than exit if there an invalid number, then you would want the code to be inside the loop.

Using grep and sed to find and replace a string

My use case was I wanted to replace foo:/Drive_Letter with foo:/bar/baz/xyz In my case I was able to do it with the following code. I was in the same directory location where there were bulk of files.

find . -name "*.library" -print0 | xargs -0 sed -i '' -e 's/foo:\/Drive_Letter:/foo:\/bar\/baz\/xyz/g'

hope that helped.

How do I show a running clock in Excel?

See the below code (taken from this post)

Put this code in a Module in VBA (Developer Tab -> Visual Basic)

Dim TimerActive As Boolean
Sub StartTimer()
    Start_Timer
End Sub
Private Sub Start_Timer()
    TimerActive = True
    Application.OnTime Now() + TimeValue("00:01:00"), "Timer"
End Sub
Private Sub Stop_Timer()
    TimerActive = False
End Sub
Private Sub Timer()
    If TimerActive Then
        ActiveSheet.Cells(1, 1).Value = Time
        Application.OnTime Now() + TimeValue("00:01:00"), "Timer"
    End If
End Sub

You can invoke the "StartTimer" function when the workbook opens and have it repeat every minute by adding the below code to your workbooks Visual Basic "This.Workbook" class in the Visual Basic editor.

Private Sub Workbook_Open()
    Module1.StartTimer
End Sub

Now, every time 1 minute passes the Timer procedure will be invoked, and set cell A1 equal to the current time.

Good tool to visualise database schema?

I found SchemaSpy quite good - you have to run the script every time schema changes but it is not so big deal.

As pointed out in the comments there is also a GUI for it.

Another nice tool is SchemaCrawler.

Node.js https pem error: routines:PEM_read_bio:no start line

I actually just had this same error message.

The problem was I had key and cert files swapped in the configuration object.

Clear data in MySQL table with PHP?

TRUNCATE TABLE mytable

Be careful with it though.

What is the perfect counterpart in Python for "while not EOF"

In addition to @dawg's great answer, the equivalent solution using walrus operator (Python >= 3.8):

with open(filename, 'rb') as f:
    while buf := f.read(max_size):
        process(buf)

Making a POST call instead of GET using urllib2

Do it in stages, and modify the object, like this:

# make a string with the request type in it:
method = "POST"
# create a handler. you can specify different handlers here (file uploads etc)
# but we go for the default
handler = urllib2.HTTPHandler()
# create an openerdirector instance
opener = urllib2.build_opener(handler)
# build a request
data = urllib.urlencode(dictionary_of_POST_fields_or_None)
request = urllib2.Request(url, data=data)
# add any other information you want
request.add_header("Content-Type",'application/json')
# overload the get method function with a small anonymous function...
request.get_method = lambda: method
# try it; don't forget to catch the result
try:
    connection = opener.open(request)
except urllib2.HTTPError,e:
    connection = e

# check. Substitute with appropriate HTTP code.
if connection.code == 200:
    data = connection.read()
else:
    # handle the error case. connection.read() will still contain data
    # if any was returned, but it probably won't be of any use

This way allows you to extend to making PUT, DELETE, HEAD and OPTIONS requests too, simply by substituting the value of method or even wrapping it up in a function. Depending on what you're trying to do, you may also need a different HTTP handler, e.g. for multi file upload.

jQuery show/hide options from one select drop down, when option on other select dropdown is slected

Initialy both dropdown have same option ,the option you select in firstdropdown is hidden in seconddropdown."value" is custom attribute which is unique.

$(".seconddropdown option" ).each(function() {
    if(($(this).attr('value')==$(".firstdropdown  option:selected").attr('value') )){
        $(this).hide();
        $(this).siblings().show();
    }
});

Limit to 2 decimal places with a simple pipe

Currency pipe uses the number one internally for number formatting. So you can use it like this:

{{ number | number : '1.2-2'}}

How much data can a List can hold at the maximum?

Numbering an items in the java array should start from zero. This was i think we can have access to Integer.MAX_VALUE+1 an items.

How to adjust gutter in Bootstrap 3 grid system?

You could create a CSS class for this and apply it to your columns. Since the gutter (spacing between columns) is controlled by padding in Bootstrap 3, adjust the padding accordingly:

.col {
  padding-right:7px;
  padding-left:7px;
}

Demo: http://bootply.com/93473

EDIT If you only want the spacing between columns you can select all cols except first and last like this..

.col:not(:first-child,:last-child) {
  padding-right:7px;
  padding-left:7px;
}

Updated Bootply

For Bootstrap 4 see: Remove gutter space for a specific div only

Angular 4 - get input value

If you dont want to use two way data binding. You can do this.

In HTML

<form (ngSubmit)="onSubmit($event)">
   <input name="player" value="Name">
</form>

In component

onSubmit(event: any) {
   return event.target.player.value;
}

Java - Check Not Null/Empty else assign default value

In Java 9, if you have an object which has another object as property and that nested objects has a method yielding a string, then you can use this construct to return an empty string if the embeded object is null :

String label = Optional.ofNullable(org.getDiffusion()).map(Diffusion::getLabel).orElse("")

In this example :

  • org is an instance of an object of type Organism
  • Organism has a Diffusion property (another object)
  • Diffusion has a String label property (and getLabel() getter).

With this example, if org.getDiffusion() is not null, then it returns the getLabel property of its Diffusion object (this returns a String). Otherwise, it returns an empty string.

How do I change the value of a global variable inside of a function

Just reference the variable inside the function; no magic, just use it's name. If it's been created globally, then you'll be updating the global variable.

You can override this behaviour by declaring it locally using var, but if you don't use var, then a variable name used in a function will be global if that variable has been declared globally.

That's why it's considered best practice to always declare your variables explicitly with var. Because if you forget it, you can start messing with globals by accident. It's an easy mistake to make. But in your case, this turn around and becomes an easy answer to your question.

Minimum 6 characters regex expression

Something along the lines of this?

<asp:TextBox id="txtUsername" runat="server" />

<asp:RegularExpressionValidator
    id="RegularExpressionValidator1"
    runat="server"
    ErrorMessage="Field not valid!"
    ControlToValidate="txtUsername"
    ValidationExpression="[0-9a-zA-Z]{6,}" />

Convert object array to hash map, indexed by an attribute value of the Object

With lodash:

const items = [
    { key: 'foo', value: 'bar' },
    { key: 'hello', value: 'world' }
];

const map = _.fromPairs(items.map(item => [item.key, item.val]));

// OR: if you want to index the whole item by key:
// const map = _.fromPairs(items.map(item => [item.key, item]));

The lodash fromPairs function reminds me about zip function in Python

Link to lodash

How do I "shake" an Android device within the Android emulator to bring up the dev menu to debug my React Native app

I was trying on a release build via adb install -r -d <app-release>.apk

Make sure you're running the debug build, then the menu will work via the shortcut or CLI.

remove duplicates from sql union

Union will remove duplicates. Union All does not.

Display animated GIF in iOS

#import <QuickLook/QuickLook.h>
#import "ViewController.h"

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    QLPreviewController *preview = [[QLPreviewController alloc] init];
    preview.dataSource = self;

    [self addChildViewController:preview];
    [self.view addSubview:preview.view];
}

#pragma mark - QLPreviewControllerDataSource

- (NSInteger)numberOfPreviewItemsInPreviewController:(QLPreviewController *)previewController
{
    return 1;
}

- (id)previewController:(QLPreviewController *)previewController previewItemAtIndex:(NSInteger)idx
{
    NSURL *fileURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"myanimated.gif" ofType:nil]];
    return fileURL;
}

@end

php $_POST array empty upon form submission

Having the enable_post_data_reading setting disabled will cause this. According to the documentation:

enable_post_data_reading

Disabling this option causes $_POST and $_FILES not to be populated. The only way to read postdata will then be through the php://input stream wrapper. This can be useful to proxy requests or to process the POST data in a memory efficient fashion.

Visual Studio can't build due to rc.exe

This can be caused by a vcxproj that originated in previous versions of Visual Studio OR changing the Platform Toolset in Configuration Properties -> General.

If so, possible Solution:

1) Go to Configuration Properties -> VC++ Directories

2) Select drop down for Executable Directories

3) Select "Inherit from parent or Project Defaults"

Uncaught SyntaxError: Unexpected token with JSON.parse

[
  {
    "name": "Pizza",
    "price": "10",
    "quantity": "7"
  },
  {
    "name": "Cerveja",
    "price": "12",
    "quantity": "5"
  },
  {
    "name": "Hamburguer",
    "price": "10",
    "quantity": "2"
  },
  {
    "name": "Fraldas",
    "price": "6",
    "quantity": "2"
  }
]

Here is your perfect Json that you can parse.

Epoch vs Iteration when training neural networks

epoch

A full training pass over the entire dataset such that each example has been seen once. Thus, an epoch represents N/batch size training iterations, where N is the total number of examples.

iteration

A single update of a model's weights during training. An iteration consists of computing the gradients of the parameters with respect to the loss on a single batch of data.

as bonus:

batch

The set of examples used in one iteration (that is, one gradient update) of model training.

See also batch size.

source: https://developers.google.com/machine-learning/glossary/

PANIC: Cannot find AVD system path. Please define ANDROID_SDK_ROOT (in windows 10)

define ANDROID_SDK_ROOT as environment variable where your SDK is residing, default path would be "C:\Program Files (x86)\Android\android-sdk" and restart computer to take effect.

Asp.Net MVC with Drop Down List, and SelectListItem Assistance

You have a view model to which your view is strongly typed => use strongly typed helpers:

<%= Html.DropDownListFor(
    x => x.SelectedAccountId, 
    new SelectList(Model.Accounts, "Value", "Text")
) %>

Also notice that I use a SelectList for the second argument.

And in your controller action you were returning the view model passed as argument and not the one you constructed inside the action which had the Accounts property correctly setup so this could be problematic. I've cleaned it a bit:

public ActionResult AccountTransaction()
{
    var accounts = Services.AccountServices.GetAccounts(false);
    var viewModel = new AccountTransactionView
    {
        Accounts = accounts.Select(a => new SelectListItem
        {
            Text = a.Description,
            Value = a.AccountId.ToString()
        })
    };
    return View(viewModel);
}

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

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

SELECT owner, directory_name, directory_path
  FROM all_directories

Updating state on props change in React Form

componentWillReceiveProps is being deprecated because using it "often leads to bugs and inconsistencies".

If something changes from the outside, consider resetting the child component entirely with key.

Providing a key prop to the child component makes sure that whenever the value of key changes from the outside, this component is re-rendered. E.g.,

<EmailInput
  defaultEmail={this.props.user.email}
  key={this.props.user.id}
/>

On its performance:

While this may sound slow, the performance difference is usually insignificant. Using a key can even be faster if the components have heavy logic that runs on updates since diffing gets bypassed for that subtree.

PostgreSQL 'NOT IN' and subquery

When using NOT IN, you should also consider NOT EXISTS, which handles the null cases silently. See also PostgreSQL Wiki

SELECT mac, creation_date 
FROM logs lo
WHERE logs_type_id=11
AND NOT EXISTS (
  SELECT *
  FROM consols nx
  WHERE nx.mac = lo.mac
  );

How to get the current time in Python

>>> from time import gmtime, strftime
>>> strftime("%a, %d %b %Y %X +0000", gmtime())
'Tue, 06 Jan 2009 04:54:56 +0000'

That outputs the current GMT in the specified format. There is also a localtime() method.

This page has more details.

Check/Uncheck checkbox with JavaScript

If, for some reason, you don't want to (or can't) run a .click() on the checkbox element, you can simply change its value directly via its .checked property (an IDL attribute of <input type="checkbox">).

Note that doing so does not fire the normally related event (change) so you'll need to manually fire it to have a complete solution that works with any related event handlers.

Here's a functional example in raw javascript (ES6):

_x000D_
_x000D_
class ButtonCheck {_x000D_
  constructor() {_x000D_
    let ourCheckBox = null;_x000D_
    this.ourCheckBox = document.querySelector('#checkboxID');_x000D_
_x000D_
    let checkBoxButton = null;_x000D_
    this.checkBoxButton = document.querySelector('#checkboxID+button[aria-label="checkboxID"]');_x000D_
_x000D_
    let checkEvent = new Event('change');_x000D_
    _x000D_
    this.checkBoxButton.addEventListener('click', function() {_x000D_
      let checkBox = this.ourCheckBox;_x000D_
_x000D_
      //toggle the checkbox: invert its state!_x000D_
      checkBox.checked = !checkBox.checked;_x000D_
_x000D_
      //let other things know the checkbox changed_x000D_
      checkBox.dispatchEvent(checkEvent);_x000D_
    }.bind(this), true);_x000D_
_x000D_
    this.eventHandler = function(e) {_x000D_
      document.querySelector('.checkboxfeedback').insertAdjacentHTML('beforeend', '<br />Event occurred on checkbox! Type: ' + e.type + ' checkbox state now: ' + this.ourCheckBox.checked);_x000D_
_x000D_
    }_x000D_
_x000D_
_x000D_
    //demonstration: we will see change events regardless of whether the checkbox is clicked or the button_x000D_
_x000D_
    this.ourCheckBox.addEventListener('change', function(e) {_x000D_
      this.eventHandler(e);_x000D_
    }.bind(this), true);_x000D_
_x000D_
    //demonstration: if we bind a click handler only to the checkbox, we only see clicks from the checkbox_x000D_
_x000D_
    this.ourCheckBox.addEventListener('click', function(e) {_x000D_
      this.eventHandler(e);_x000D_
    }.bind(this), true);_x000D_
_x000D_
_x000D_
  }_x000D_
}_x000D_
_x000D_
var init = function() {_x000D_
  const checkIt = new ButtonCheck();_x000D_
}_x000D_
_x000D_
if (document.readyState != 'loading') {_x000D_
  init;_x000D_
} else {_x000D_
  document.addEventListener('DOMContentLoaded', init);_x000D_
}
_x000D_
<input type="checkbox" id="checkboxID" />_x000D_
_x000D_
<button aria-label="checkboxID">Change the checkbox!</button>_x000D_
_x000D_
<div class="checkboxfeedback">No changes yet!</div>
_x000D_
_x000D_
_x000D_

If you run this and click on both the checkbox and the button you should get a sense of how this works.

Note that I used document.querySelector for brevity/simplicity, but this could easily be built out to either have a given ID passed to the constructor, or it could apply to all buttons that act as aria-labels for a checkbox (note that I didn't bother setting an id on the button and giving the checkbox an aria-labelledby, which should be done if using this method) or any number of other ways to expand this. The last two addEventListeners are just to demo how it works.

Pandas Merging 101

A supplemental visual view of pd.concat([df0, df1], kwargs). Notice that, kwarg axis=0 or axis=1 's meaning is not as intuitive as df.mean() or df.apply(func)


on pd.concat([df0, df1])

How to convert a date string to different format

If you can live with 01 for January instead of 1, then try...

d = datetime.datetime.strptime("2013-1-25", '%Y-%m-%d')
print datetime.date.strftime(d, "%m/%d/%y")

You can check the docs for other formatting directives.

What is the purpose of the "final" keyword in C++11 for functions?

The final keyword allows you to declare a virtual method, override it N times, and then mandate that 'this can no longer be overridden'. It would be useful in restricting use of your derived class, so that you can say "I know my super class lets you override this, but if you want to derive from me, you can't!".

struct Foo
{
   virtual void DoStuff();
}

struct Bar : public Foo
{
   void DoStuff() final;
}

struct Babar : public Bar
{
   void DoStuff(); // error!
}

As other posters pointed out, it cannot be applied to non-virtual functions.

One purpose of the final keyword is to prevent accidental overriding of a method. In my example, DoStuff() may have been a helper function that the derived class simply needs to rename to get correct behavior. Without final, the error would not be discovered until testing.

Illegal access: this web application instance has been stopped already

In short: this happens likely when you are hot-deploying webapps. For instance, your ide+development server hot-deploys a war again. Threads, that have been created previously are still running. But meanwhile their classloader/context is invalid and faces the IllegalAccessException / IllegalStateException becouse its orgininating webapp (the former runtime-environment) has been redeployed.

So, as states here, a restart does not permanently resolve this issue. Instead, it is better to find/implement a managed Thread Pool, s.th. like this to handle the termination of threads appropriately. In JavaEE you will use these ManagedThreadExeuctorServices. A similar opinion and reference here.

Examples for this are the EvictorThread of Apache Commons Pool, that "cleans" pooled instances according to the pool's configuration (max idle etc.).

How do you set the width of an HTML Helper TextBox in ASP.NET MVC?

Something like this should work:

<%=Html.TextBox("test", new { style="width:50px" })%>

Or better:

<%=Html.TextBox("test")%>

<style type="text/css">
    input[type="text"] { width:50px; }     
</style>

how to make a countdown timer in java

You'll see people using the Timer class to do this. Unfortunately, it isn't always accurate. Your best bet is to get the system time when the user enters input, calculate a target system time, and check if the system time has exceeded the target system time. If it has, then break out of the loop.

how do I strip white space when grabbing text with jQuery?

Use the replace function in js:

var emailAdd = $(this).text().replace(/ /g,'');

That will remove all the spaces

If you want to remove the leading and trailing whitespace only, use the jQuery $.trim method :

var emailAdd = $.trim($(this).text());

UnicodeEncodeError: 'latin-1' codec can't encode character

I hope your database is at least UTF-8. Then you will need to run yourstring.encode('utf-8') before you try putting it into the database.

How to add form validation pattern in Angular 2?

My solution with Angular 4.0.1: Just showing the UI for required CVC input - where the CVC must be exactly 3 digits:

    <form #paymentCardForm="ngForm">         
...
        <md-input-container align="start">
            <input #cvc2="ngModel" mdInput type="text" id="cvc2" name="cvc2" minlength="3" maxlength="3" placeholder="CVC" [(ngModel)]="paymentCard.cvc2" [disabled]="isBusy" pattern="\d{3}" required />
            <md-hint *ngIf="cvc2.errors && (cvc2.touched || submitted)" class="validation-result">
                <span [hidden]="!cvc2.errors.required && cvc2.dirty">
                    CVC is required.
                </span>
                <span [hidden]="!cvc2.errors.minlength && !cvc2.errors.maxlength && !cvc2.errors.pattern">
                    CVC must be 3 numbers.
                </span>
            </md-hint>
        </md-input-container>
...
<button type="submit" md-raised-button color="primary" (click)="confirm($event, paymentCardForm.value)" [disabled]="isBusy || !paymentCardForm.valid">Confirm</button>
</form>

Difference between objectForKey and valueForKey?

objectForKey: is an NSDictionary method. An NSDictionary is a collection class similar to an NSArray, except instead of using indexes, it uses keys to differentiate between items. A key is an arbitrary string you provide. No two objects can have the same key (just as no two objects in an NSArray can have the same index).

valueForKey: is a KVC method. It works with ANY class. valueForKey: allows you to access a property using a string for its name. So for instance, if I have an Account class with a property accountNumber, I can do the following:

NSNumber *anAccountNumber = [NSNumber numberWithInt:12345];
Account *newAccount = [[Account alloc] init];

[newAccount setAccountNumber:anAccountNUmber];

NSNumber *anotherAccountNumber = [newAccount accountNumber];

Using KVC, I can access the property dynamically:

NSNumber *anAccountNumber = [NSNumber numberWithInt:12345];
Account *newAccount = [[Account alloc] init];

[newAccount setValue:anAccountNumber forKey:@"accountNumber"];

NSNumber *anotherAccountNumber = [newAccount valueForKey:@"accountNumber"];

Those are equivalent sets of statements.

I know you're thinking: wow, but sarcastically. KVC doesn't look all that useful. In fact, it looks "wordy". But when you want to change things at runtime, you can do lots of cool things that are much more difficult in other languages (but this is beyond the scope of your question).

If you want to learn more about KVC, there are many tutorials if you Google especially at Scott Stevenson's blog. You can also check out the NSKeyValueCoding Protocol Reference.

Hope that helps.

MySQL limit from descending order

Let's say we have a table with a column time and you want the last 5 entries, but you want them returned to you in asc order, not desc, this is how you do it:

select * from ( select * from `table` order by `time` desc limit 5 ) t order by `time` asc

Does Enter key trigger a click event?

Use (keyup.enter).

Angular can filter the key events for us. Angular has a special syntax for keyboard events. We can listen for just the Enter key by binding to Angular's keyup.enter pseudo-event.

How to specify maven's distributionManagement organisation wide?

The best solution for this is to create a simple parent pom file project (with packaging 'pom') generically for all projects from your organization.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>your.company</groupId>
    <artifactId>company-parent</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <distributionManagement>
        <repository>
            <id>nexus-site</id>
            <url>http://central_nexus/server</url>
        </repository>
    </distributionManagement>

</project>

This can be built, released, and deployed to your local nexus so everyone has access to its artifact.

Now for all projects which you wish to use it, simply include this section:

<parent>
  <groupId>your.company</groupId>
  <artifactId>company-parent</artifactId>
  <version>1.0.0</version>
</parent>

This solution will allow you to easily add other common things to all your company's projects. For instance if you wanted to standardize your JUnit usage to a specific version, this would be the perfect place for that.

If you have projects that use multi-module structures that have their own parent, Maven also supports chaining inheritance so it is perfectly acceptable to make your project's parent pom file refer to your company's parent pom and have the project's child modules not even aware of your company's parent.

I see from your example project structure that you are attempting to put your parent project at the same level as your aggregator pom. If your project needs its own parent, the best approach I have found is to include the parent at the same level as the rest of the modules and have your aggregator pom.xml file at the root of where all your modules' directories exist.

- pom.xml (aggregator)
    - project-parent
    - project-module1
    - project-module2

What you do with this structure is include your parent module in the aggregator and build everything with a mvn install from the root directory.

We use this exact solution at my organization and it has stood the test of time and worked quite well for us.

How to uninstall Ruby from /usr/local?

Create a symlink at /usr/bin named 'ruby' and point it to the latest installed ruby.

You can use something like ln -s /usr/bin/ruby /to/the/installed/ruby/binary

Hope this helps.

Using Linq select list inside list

list.Where(m => m.application == "applicationName" && 
           m.users.Any(u => u.surname=="surname"));

if you want to filter users as TimSchmelter commented, you can use

list.Where(m => m.application == "applicationName")
    .Select(m => new Model
    {
        application = m.application,
        users = m.users.Where(u => u.surname=="surname").ToList()
    });

How to get the index of an element in an IEnumerable?

An alternative to finding the index after the fact is to wrap the Enumerable, somewhat similar to using the Linq GroupBy() method.

public static class IndexedEnumerable
{
    public static IndexedEnumerable<T> ToIndexed<T>(this IEnumerable<T> items)
    {
        return IndexedEnumerable<T>.Create(items);
    }
}

public class IndexedEnumerable<T> : IEnumerable<IndexedEnumerable<T>.IndexedItem>
{
    private readonly IEnumerable<IndexedItem> _items;

    public IndexedEnumerable(IEnumerable<IndexedItem> items)
    {
        _items = items;
    }

    public class IndexedItem
    {
        public IndexedItem(int index, T value)
        {
            Index = index;
            Value = value;
        }

        public T Value { get; private set; }
        public int Index { get; private set; }
    }

    public static IndexedEnumerable<T> Create(IEnumerable<T> items)
    {
        return new IndexedEnumerable<T>(items.Select((item, index) => new IndexedItem(index, item)));
    }

    public IEnumerator<IndexedItem> GetEnumerator()
    {
        return _items.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

Which gives a use case of:

var items = new[] {1, 2, 3};
var indexedItems = items.ToIndexed();
foreach (var item in indexedItems)
{
    Console.WriteLine("items[{0}] = {1}", item.Index, item.Value);
}

How to detect when keyboard is shown and hidden

Swift - 4

override func viewWillAppear(_ animated: Bool) {
   super.viewWillAppear(animated)
   addKeyBoardListener()
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self) //remove observer
}

func addKeyBoardListener() {
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(_:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil);
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide(_:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil);
}

@objc func keyboardWillShow(_ notification: Notification) {

}

@objc func keyboardWillHide(_ notification: Notification) {

}

Shortcut key for commenting out lines of Python code in Spyder

  • Single line comment

    Ctrl + 1

  • Multi-line comment select the lines to be commented

    Ctrl + 4

  • Unblock Multi-line comment

    Ctrl + 5

Calling a phone number in swift

Many of the other answers don't work for Swift 5. Below is the code update to Swift 5:

let formattedNumber = phoneNumberVariable.components(separatedBy: NSCharacterSet.decimalDigits.inverted).joined(separator: "")

if let url = NSURL(string: ("tel:" + (formattedNumber)!)) {
    if #available(iOS 10.0, *) {
        UIApplication.shared.open(url as URL, options: [:], completionHandler: nil)
    } else {
        UIApplication.shared.openURL(url as URL)
    }
}

PS:

  1. With most of the answers, I wasn't able to get the prompt on the device. The above code was successfully able to display the prompt.
  2. There is no // after tel: like most answers have. And it works fine.

Error while waiting for device: Time out after 300seconds waiting for emulator to come online

I've face this problem, i fixed it by deleting the emulator then created a new one with higher API level.

In my case I've created API-30

Difference between VARCHAR and TEXT in MySQL

There is an important detail that has been omitted in the answer above.

MySQL imposes a limit of 65,535 bytes for the max size of each row. The size of a VARCHAR column is counted towards the maximum row size, while TEXT columns are assumed to be storing their data by reference so they only need 9-12 bytes. That means even if the "theoretical" max size of your VARCHAR field is 65,535 characters you won't be able to achieve that if you have more than one column in your table.

Also note that the actual number of bytes required by a VARCHAR field is dependent on the encoding of the column (and the content). MySQL counts the maximum possible bytes used toward the max row size, so if you use a multibyte encoding like utf8mb4 (which you almost certainly should) it will use up even more of your maximum row size.

Correction: Regardless of how MySQL computes the max row size, whether or not the VARCHAR/TEXT field data is ACTUALLY stored in the row or stored by reference depends on your underlying storage engine. For InnoDB the row format affects this behavior. (Thanks Bill-Karwin)

Reasons to use TEXT:

  • If you want to store a paragraph or more of text
  • If you don't need to index the column
  • If you have reached the row size limit for your table

Reasons to use VARCHAR:

  • If you want to store a few words or a sentence
  • If you want to index the (entire) column
  • If you want to use the column with foreign-key constraints

Convert String array to ArrayList

in most cases the List<String> should be enough. No need to create an ArrayList

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

...

String[] words={"ace","boom","crew","dog","eon"};
List<String> l = Arrays.<String>asList(words);

// if List<String> isnt specific enough:
ArrayList<String> al = new ArrayList<String>(l);

How to do associative array/hashing in JavaScript

All modern browsers support a JavaScript Map object. There are a couple of reasons that make using a Map better than Object:

  • An Object has a prototype, so there are default keys in the map.
  • The keys of an Object are Strings, where they can be any value for a Map.
  • You can get the size of a Map easily while you have to keep track of size for an Object.

Example:

var myMap = new Map();

var keyObj = {},
    keyFunc = function () {},
    keyString = "a string";

myMap.set(keyString, "value associated with 'a string'");
myMap.set(keyObj, "value associated with keyObj");
myMap.set(keyFunc, "value associated with keyFunc");

myMap.size; // 3

myMap.get(keyString);    // "value associated with 'a string'"
myMap.get(keyObj);       // "value associated with keyObj"
myMap.get(keyFunc);      // "value associated with keyFunc"

If you want keys that are not referenced from other objects to be garbage collected, consider using a WeakMap instead of a Map.

Xcode "Device Locked" When iPhone is unlocked

This issue is not about "Trust" or not. It's a bug in Xcode.

Just follow these steps.

When Xcode is running and your device is connected:

  1. Lock your device.
  2. Unplug your device from Mac.
  3. Unlock your device.
  4. Plug your device back to Mac.

Why is division in Ruby returning an integer instead of decimal value?

Fixnum#to_r is not mentioned here, it was introduced since ruby 1.9. It converts Fixnum into rational form. Below are examples of its uses. This also can give exact division as long as all the numbers used are Fixnum.

 a = 1.to_r  #=> (1/1) 
 a = 10.to_r #=> (10/1) 
 a = a / 3   #=> (10/3) 
 a = a * 3   #=> (10/1) 
 a.to_f      #=> 10.0

Example where a float operated on a rational number coverts the result to float.

a = 5.to_r   #=> (5/1) 
a = a * 5.0  #=> 25.0 

Responsive bootstrap 3 timepicker?

As an update to the OP's question, I can confirm that the timepicker found at http://jdewit.github.io/bootstrap-timepicker/ does in fact work with Bootstrap 3 now with no problems at all.

Minimum rights required to run a windows service as a domain account

I do know that the account needs to have "Log on as a Service" privileges. Other than that, I'm not sure. A quick reference to Log on as a Service can be found here, and there is a lot of information of specific privileges here.

java.lang.OutOfMemoryError: Java heap space

  1. Upto my knowledge, Heap space is occupied by instance variables only. If this is correct, then why this error occurred after running fine for sometime as space for instance variables are alloted at the time of object creation.

That means you are creating more objects in your application over a period of time continuously. New objects will be stored in heap memory and that's the reason for growth in heap memory.

Heap not only contains instance variables. It will store all non-primitive data types ( Objects). These objects life time may be short (method block) or long (till the object is referenced in your application)

  1. Is there any way to increase the heap space?

Yes. Have a look at this oracle article for more details.

There are two parameters for setting the heap size:

-Xms:, which sets the initial and minimum heap size

-Xmx:, which sets the maximum heap size

  1. What changes should I made to my program so that It will grab less heap space?

It depends on your application.

  1. Set the maximum heap memory as per your application requirement

  2. Don't cause memory leaks in your application

  3. If you find memory leaks in your application, find the root cause with help of profiling tools like MAT, Visual VM , jconsole etc. Once you find the root cause, fix the leaks.

Important notes from oracle article

Cause: The detail message Java heap space indicates object could not be allocated in the Java heap. This error does not necessarily imply a memory leak.

Possible reasons:

  1. Improper configuration ( not allocating sufficiant memory)
  2. Application is unintentionally holding references to objects and this prevents the objects from being garbage collected
  3. Applications that make excessive use of finalizers. If a class has a finalize method, then objects of that type do not have their space reclaimed at garbage collection time. If the finalizer thread cannot keep up, with the finalization queue, then the Java heap could fill up and this type of OutOfMemoryError exception would be thrown.

On a different note, use better Garbage collection algorithms ( CMS or G1GC)

Have a look at this question for understanding G1GC

How to compile c# in Microsoft's new Visual Studio Code?

Install the extension "Code Runner". Check if you can compile your program with csc (ex.: csc hello.cs). The command csc is shipped with Mono. Then add this to your VS Code user settings:

"code-runner.executorMap": {
        "csharp": "echo '# calling mono\n' && cd $dir && csc /nologo $fileName && mono $dir$fileNameWithoutExt.exe",
        // "csharp": "echo '# calling dotnet run\n' && dotnet run"
    }

Open your C# file and use the execution key of Code Runner.

Edit: also added dotnet run, so you can choose how you want to execute your program: with Mono, or with dotnet. If you choose dotnet, then first create the project (dotnet new console, dotnet restore).

How to set breakpoints in inline Javascript in Google Chrome?

Use the sources tab, you can set breakpoints in JavaScript there. In the directory tree underneath it (with the up and down arrow in it), you can select the file you want to debug. You can get out of an error by pressing resume on the right-hand side of the same tab.

Where can I find the error logs of nginx, using FastCGI and Django?

Run this command, to check error logs:

tail -f /var/log/nginx/error.log

What is the difference between '@' and '=' in directive scope in AngularJS?

Simply we can use:-

  1. @ :- for String values for one way Data binding. in one way data binding you can only pass scope value to directive

  2. = :- for object value for two way data binding. in two way data binding you can change the scope value in directive as well as in html also.

  3. & :- for methods and functions.

EDIT

In our Component definition for Angular version 1.5 And above
there are four different type of bindings:

  1. = Two-way data binding :- if we change the value,it automatically update
  2. < one way binding :- when we just want to read a parameter from a parent scope and not update it.

  3. @ this is for String Parameters

  4. & this is for Callbacks in case your component needs to output something to its parent scope

In log4j, does checking isDebugEnabled before logging improve performance?

Log4j2 lets you format parameters into a message template, similar to String.format(), thus doing away with the need to do isDebugEnabled().

Logger log = LogManager.getFormatterLogger(getClass());
log.debug("Some message [myField=%s]", myField);

Sample simple log4j2.properties:

filter.threshold.type = ThresholdFilter
filter.threshold.level = debug
appender.console.type = Console
appender.console.name = STDOUT
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = %d %-5p: %c - %m%n
appender.console.filter.threshold.type = ThresholdFilter
appender.console.filter.threshold.level = debug
rootLogger.level = info
rootLogger.appenderRef.stdout.ref = STDOUT

How to convert Map keys to array?

Array.from(myMap.keys()) does not work in google application scripts.

Trying to use it results in the error TypeError: Cannot find function from in object function Array() { [native code for Array.Array, arity=1] }.

To get a list of keys in GAS do this:

var keysList = Object.keys(myMap);

Downloading all maven dependencies to a directory NOT in repository?

Based on @Raghuram answer, I find a tutorial on Copying project dependencies, Just:

  1. Open your project pom.xml file and find this:

    <project>
      [...]
      <build>
        <plugins>
          ...
        </plugins>
      </build>
      [...]
    </project>
    
  2. Than replace the <plugins> ... </plugins> with:

    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <version>3.0.0</version>
        <executions>
          <execution>
            <id>copy-dependencies</id>
            <phase>package</phase>
            <goals>
              <goal>copy-dependencies</goal>
            </goals>
            <configuration>
              <outputDirectory>${project.build.directory}/alternateLocation</outputDirectory>
              <overWriteReleases>false</overWriteReleases>
              <overWriteSnapshots>false</overWriteSnapshots>
              <overWriteIfNewer>true</overWriteIfNewer>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
    
  3. And call maven within the command line mvn dependency:copy-dependencies

After it finishes, it will create the folder target/dependency within all the jar's dependencies on the current directory where the pom.xml lives.

How do I increase the contrast of an image in Python OpenCV

Best explanation for X = aY + b (in fact it f(x) = ax + b)) is provided at https://math.stackexchange.com/a/906280/357701

A Simpler one by just adjusting lightness/luma/brightness for contrast as is below:

import cv2

img = cv2.imread('test.jpg')
cv2.imshow('test', img)
cv2.waitKey(1000)
imghsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)


imghsv[:,:,2] = [[max(pixel - 25, 0) if pixel < 190 else min(pixel + 25, 255) for pixel in row] for row in imghsv[:,:,2]]
cv2.imshow('contrast', cv2.cvtColor(imghsv, cv2.COLOR_HSV2BGR))
cv2.waitKey(1000)
raw_input()

What properties can I use with event.target?

event.target returns the DOM element, so you can retrieve any property/ attribute that has a value; so, to answer your question more specifically, you will always be able to retrieve nodeName, and you can retrieve href and id, provided the element has a href and id defined; otherwise undefined will be returned.

However, inside an event handler, you can use this, which is set to the DOM element as well; much easier.

$('foo').bind('click', function () {
    // inside here, `this` will refer to the foo that was clicked
});

Laravel 5 Application Key

For me the problem was in that I had not yet ran composer update for this new project/fork. The command failed silently, nothing happened.

After running composer update it worked.

How does delete[] know it's an array?

The compiler doesn't know it's an array, it's trusting the programmer. Deleting a pointer to a single int with delete [] would result in undefined behavior. Your second main() example is unsafe, even if it doesn't immediately crash.

The compiler does have to keep track of how many objects need to be deleted somehow. It may do this by over-allocating enough to store the array size. For more details, see the C++ Super FAQ.

How to link to apps on the app store

This is working and directly linking in ios5

NSString *iTunesLink = @"http://itunes.apple.com/app/baseball-stats-tracker-touch/id490256272?mt=8";  
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:iTunesLink]];

Convert an image to grayscale in HTML/CSS

Try this jquery plugin. Although, this is not a pure HTML and CSS solution, but it is a lazy way to achieve what you want. You can customize your greyscale to best suit your usage. Use it as follow:

$("#myImageID").tancolor();

There's an interactive demo. You can play around with it.

Check out the documentation on the usage, it is pretty simple. docs

Pass a reference to DOM object with ng-click

While you do the following, technically speaking:

<button ng-click="doSomething($event)"></button>
// In controller:
$scope.doSomething = function($event) {
  //reference to the button that triggered the function:
  $event.target
};

This is probably something you don't want to do as AngularJS philosophy is to focus on model manipulation and let AngularJS do the rendering (based on hints from the declarative UI). Manipulating DOM elements and attributes from a controller is a big no-no in AngularJS world.

You might check this answer for more info: https://stackoverflow.com/a/12431211/1418796

Java String array: is there a size of method?

There is a difference between length of String and array to clarify:

int a[] = {1, 2, 3, 4};
String s = "1234";

a.length //gives the length of the array

s.length() //gives the length of the string

Uncaught TypeError: undefined is not a function on loading jquery-min.js

I got this when I accidentally passed too many parameters into a jquery function that only expected one callback parameter.

For others troubleshooting: make sure you check all your jquery function calls for extra parameters.

Remove an item from an IEnumerable<T> collection

You can not remove an item from an IEnumerable; it can only be enumerated, as described here: http://msdn.microsoft.com/en-us/library/system.collections.ienumerable.aspx

You have to use an ICollection if you want to add and remove items. Maybe you can try and casting your IEnumerable; this will off course only work if the underlying object implements ICollection`.

See here for more on ICollection: http://msdn.microsoft.com/en-us/library/92t2ye13.aspx

You can, of course, just create a new list from your IEnumerable, as pointed out by lante, but this might be "sub optimal", depending on your actual use case, of course.

ICollection is probably the way to go.

How to get current moment in ISO 8601 format with date, hour, and minute?

Java 8:

thisMoment = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mmX")
                              .withZone(ZoneOffset.UTC)
                              .format(Instant.now());

Pre Java 8:

thisMoment = String.format("%tFT%<tRZ",
                           Calendar.getInstance(TimeZone.getTimeZone("Z")));

From the docs:

'R'    Time formatted for the 24-hour clock as "%tH:%tM"
'F'    ISO 8601 complete date formatted as "%tY-%tm-%td".

Java synchronized block vs. Collections.synchronizedMap

Check out Google Collections' Multimap, e.g. page 28 of this presentation.

If you can't use that library for some reason, consider using ConcurrentHashMap instead of SynchronizedHashMap; it has a nifty putIfAbsent(K,V) method with which you can atomically add the element list if it's not already there. Also, consider using CopyOnWriteArrayList for the map values if your usage patterns warrant doing so.

Best way to write to the console in PowerShell

The middle one writes to the pipeline. Write-Host and Out-Host writes to the console. 'echo' is an alias for Write-Output which writes to the pipeline as well. The best way to write to the console would be using the Write-Host cmdlet.

When an object is written to the pipeline it can be consumed by other commands in the chain. For example:

"hello world" | Do-Something

but this won't work since Write-Host writes to the console, not to the pipeline (Do-Something will not get the string):

Write-Host "hello world" | Do-Something

Convert hexadecimal string (hex) to a binary string

Integer.parseInt(hex,16);    
System.out.print(Integer.toBinaryString(hex));

Parse hex(String) to integer with base 16 then convert it to Binary String using toBinaryString(int) method

example

int num = (Integer.parseInt("A2B", 16));
System.out.print(Integer.toBinaryString(num));

Will Print

101000101011

Max Hex vakue Handled by int is FFFFFFF

i.e. if FFFFFFF0 is passed ti will give error

What is the location of mysql client ".my.cnf" in XAMPP for Windows?

Type this:

mysql --help 

Then look at the output. There is a block of text about 3/4 the way down describing what files it finds its defaults .my.cnf from. Here is an example from XAMPP v3.2.1:

Default options are read from the following files in the given order:
C:\Windows\my.ini C:\Windows\my.cnf C:\my.ini C:\my.cnf C:\xampp\mysql\my.ini C:\xampp\mysql\my.cnf C:\xampp\mysql\bin\my.ini C:\xampp\mysql\bin\my.cnf

Your setup may differ. You will have to run the command to check the actual paths on your particular system.

Turn off warnings and errors on PHP and MySQL

Always show errors on a testing server. Never show errors on a production server.

Write a script to determine whether the page is on a local, testing, or live server, and set $state to "local", "testing", or "live". Then:

if( $state == "local" || $state == "testing" )
{
    ini_set( "display_errors", "1" );
    error_reporting( E_ALL & ~E_NOTICE );
}
else
{
    error_reporting( 0 );
}

Using headers with the Python requests library's get method

This answer taught me that you can set headers for an entire session:

s = requests.Session()
s.auth = ('user', 'pass')
s.headers.update({'x-test': 'true'})

# both 'x-test' and 'x-test2' are sent
s.get('http://httpbin.org/headers', headers={'x-test2': 'true'})

Bonus: Sessions also handle cookies.

Store a cmdlet's result value in a variable in Powershell

Use the -ExpandProperty flag of Select-Object

$var=Get-WSManInstance -enumerate wmicimv2/win32_process | select -expand Priority

Update to answer the other question:

Note that you can as well just access the property:

$var=(Get-WSManInstance -enumerate wmicimv2/win32_process).Priority

So to get multiple of these into variables:

$var=Get-WSManInstance -enumerate wmicimv2/win32_process
   $prio = $var.Priority
   $pid = $var.ProcessID

How to read a text file into a list or an array with Python

This question is asking how to read the comma-separated value contents from a file into an iterable list:

0,0,200,0,53,1,0,255,...,0.

The easiest way to do this is with the csv module as follows:

import csv
with open('filename.dat', newline='') as csvfile:
    spamreader = csv.reader(csvfile, delimiter=',')

Now, you can easily iterate over spamreader like this:

for row in spamreader:
    print(', '.join(row))

See documentation for more examples.

Joining Spark dataframes on the key

From https://spark.apache.org/docs/1.5.1/api/java/org/apache/spark/sql/DataFrame.html, use join:

Inner equi-join with another DataFrame using the given column.

PersonDf.join(ProfileDf,$"personId")

OR

PersonDf.join(ProfileDf,PersonDf("personId") === ProfileDf("personId"))

Update:

You can also save the DFs as temp table using df.registerTempTable("tableName") and you can write sql queries using sqlContext.

Keras input explanation: input_shape, units, batch_size, dim, etc

Units:

The amount of "neurons", or "cells", or whatever the layer has inside it.

It's a property of each layer, and yes, it's related to the output shape (as we will see later). In your picture, except for the input layer, which is conceptually different from other layers, you have:

  • Hidden layer 1: 4 units (4 neurons)
  • Hidden layer 2: 4 units
  • Last layer: 1 unit

Shapes

Shapes are consequences of the model's configuration. Shapes are tuples representing how many elements an array or tensor has in each dimension.

Ex: a shape (30,4,10) means an array or tensor with 3 dimensions, containing 30 elements in the first dimension, 4 in the second and 10 in the third, totaling 30*4*10 = 1200 elements or numbers.

The input shape

What flows between layers are tensors. Tensors can be seen as matrices, with shapes.

In Keras, the input layer itself is not a layer, but a tensor. It's the starting tensor you send to the first hidden layer. This tensor must have the same shape as your training data.

Example: if you have 30 images of 50x50 pixels in RGB (3 channels), the shape of your input data is (30,50,50,3). Then your input layer tensor, must have this shape (see details in the "shapes in keras" section).

Each type of layer requires the input with a certain number of dimensions:

  • Dense layers require inputs as (batch_size, input_size)
    • or (batch_size, optional,...,optional, input_size)
  • 2D convolutional layers need inputs as:
    • if using channels_last: (batch_size, imageside1, imageside2, channels)
    • if using channels_first: (batch_size, channels, imageside1, imageside2)
  • 1D convolutions and recurrent layers use (batch_size, sequence_length, features)

Now, the input shape is the only one you must define, because your model cannot know it. Only you know that, based on your training data.

All the other shapes are calculated automatically based on the units and particularities of each layer.

Relation between shapes and units - The output shape

Given the input shape, all other shapes are results of layers calculations.

The "units" of each layer will define the output shape (the shape of the tensor that is produced by the layer and that will be the input of the next layer).

Each type of layer works in a particular way. Dense layers have output shape based on "units", convolutional layers have output shape based on "filters". But it's always based on some layer property. (See the documentation for what each layer outputs)

Let's show what happens with "Dense" layers, which is the type shown in your graph.

A dense layer has an output shape of (batch_size,units). So, yes, units, the property of the layer, also defines the output shape.

  • Hidden layer 1: 4 units, output shape: (batch_size,4).
  • Hidden layer 2: 4 units, output shape: (batch_size,4).
  • Last layer: 1 unit, output shape: (batch_size,1).

Weights

Weights will be entirely automatically calculated based on the input and the output shapes. Again, each type of layer works in a certain way. But the weights will be a matrix capable of transforming the input shape into the output shape by some mathematical operation.

In a dense layer, weights multiply all inputs. It's a matrix with one column per input and one row per unit, but this is often not important for basic works.

In the image, if each arrow had a multiplication number on it, all numbers together would form the weight matrix.

Shapes in Keras

Earlier, I gave an example of 30 images, 50x50 pixels and 3 channels, having an input shape of (30,50,50,3).

Since the input shape is the only one you need to define, Keras will demand it in the first layer.

But in this definition, Keras ignores the first dimension, which is the batch size. Your model should be able to deal with any batch size, so you define only the other dimensions:

input_shape = (50,50,3)
    #regardless of how many images I have, each image has this shape        

Optionally, or when it's required by certain kinds of models, you can pass the shape containing the batch size via batch_input_shape=(30,50,50,3) or batch_shape=(30,50,50,3). This limits your training possibilities to this unique batch size, so it should be used only when really required.

Either way you choose, tensors in the model will have the batch dimension.

So, even if you used input_shape=(50,50,3), when keras sends you messages, or when you print the model summary, it will show (None,50,50,3).

The first dimension is the batch size, it's None because it can vary depending on how many examples you give for training. (If you defined the batch size explicitly, then the number you defined will appear instead of None)

Also, in advanced works, when you actually operate directly on the tensors (inside Lambda layers or in the loss function, for instance), the batch size dimension will be there.

  • So, when defining the input shape, you ignore the batch size: input_shape=(50,50,3)
  • When doing operations directly on tensors, the shape will be again (30,50,50,3)
  • When keras sends you a message, the shape will be (None,50,50,3) or (30,50,50,3), depending on what type of message it sends you.

Dim

And in the end, what is dim?

If your input shape has only one dimension, you don't need to give it as a tuple, you give input_dim as a scalar number.

So, in your model, where your input layer has 3 elements, you can use any of these two:

  • input_shape=(3,) -- The comma is necessary when you have only one dimension
  • input_dim = 3

But when dealing directly with the tensors, often dim will refer to how many dimensions a tensor has. For instance a tensor with shape (25,10909) has 2 dimensions.


Defining your image in Keras

Keras has two ways of doing it, Sequential models, or the functional API Model. I don't like using the sequential model, later you will have to forget it anyway because you will want models with branches.

PS: here I ignored other aspects, such as activation functions.

With the Sequential model:

from keras.models import Sequential  
from keras.layers import *  

model = Sequential()    

#start from the first hidden layer, since the input is not actually a layer   
#but inform the shape of the input, with 3 elements.    
model.add(Dense(units=4,input_shape=(3,))) #hidden layer 1 with input

#further layers:    
model.add(Dense(units=4)) #hidden layer 2
model.add(Dense(units=1)) #output layer   

With the functional API Model:

from keras.models import Model   
from keras.layers import * 

#Start defining the input tensor:
inpTensor = Input((3,))   

#create the layers and pass them the input tensor to get the output tensor:    
hidden1Out = Dense(units=4)(inpTensor)    
hidden2Out = Dense(units=4)(hidden1Out)    
finalOut = Dense(units=1)(hidden2Out)   

#define the model's start and end points    
model = Model(inpTensor,finalOut)

Shapes of the tensors

Remember you ignore batch sizes when defining layers:

  • inpTensor: (None,3)
  • hidden1Out: (None,4)
  • hidden2Out: (None,4)
  • finalOut: (None,1)

Export SQL query data to Excel

I had a similar problem but with a twist - the solutions listed above worked when the resultset was from one query but in my situation, I had multiple individual select queries for which I needed results to be exported to Excel. Below is just an example to illustrate although I could do a name in clause...

select a,b from Table_A where name = 'x'
select a,b from Table_A where name = 'y'
select a,b from Table_A where name = 'z'

The wizard was letting me export the result from one query to excel but not all results from different queries in this case.

When I researched, I found that we could disable the results to grid and enable results to Text. So, press Ctrl + T, then execute all the statements. This should show the results as a text file in the output window. You can manipulate the text into a tab delimited format for you to import into Excel.

You could also press Ctrl + Shift + F to export the results to a file - it exports as a .rpt file that can be opened using a text editor and manipulated for excel import.

Hope this helps any others having a similar issue.

Check string for palindrome

/**
 * Check whether a word is a palindrome
 *
 * @param word the word
 * @param low  low index
 * @param high high index
 * @return {@code true} if the word is a palindrome;
 * {@code false} otherwise
 */
private static boolean isPalindrome(char[] word, int low, int high) {
    if (low >= high) {
        return true;
    } else if (word[low] != word[high]) {
        return false;
    } else {
        return isPalindrome(word, low + 1, high - 1);
    }
}

/**
 * Check whether a word is a palindrome
 *
 * @param the word
 * @return {@code true} if the word is a palindrome;
 * @code false} otherwise
 */
private static boolean isPalindrome(char[] word) {
    int length = word.length;
    for (int i = 0; i <= length / 2; i++) {
        if (word[i] != word[length - 1 - i]) {
            return false;
        }
    }
    return true;
}

public static void main(String[] args) {
    char[] word = {'a', 'b', 'c', 'b', 'a' };
    System.out.println(isPalindrome(word, 0, word.length - 1));
    System.out.println(isPalindrome(word));
}

How to change ProgressBar's progress indicator color in Android

You can use custom drawable to make your Progressbar stylable. Create a drawable file

progress_user_badge.xml

<?xml version="1.0" encoding="utf-8"?>

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:id="@android:id/background">
        <shape android:shape="rectangle">
            <corners android:radius="@dimen/_5sdp"/>
            <solid android:color="@color/your_default_color" />
        </shape>
    </item>

    <item android:id="@android:id/progress">
        <clip>
            <shape android:shape="rectangle">
                <corners android:radius="@dimen/_5sdp"/>
                <solid android:color="@color/your_exact_color" />
            </shape>
        </clip>
    </item>

</layer-list>

now use this drawable file in your widget

<ProgressBar
    android:id="@+id/badge_progress_bar"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="@dimen/_200sdp"
    android:layout_height="@dimen/_7sdp"
    android:layout_gravity="center"
    android:layout_marginTop="@dimen/_15sdp"
    android:indeterminate="false"
    android:max="100"
    android:progress="70"
    android:progressDrawable="@drawable/progress_user_badge"/>

You can use the bellow line to change the progress color of Progressbar programmatically

badge_progress_bar.progressTintList = ColorStateList.valueOf(ContextCompat.getColor(this, R.color.your_color))