Programs & Examples On #Malloc history

How to check if text fields are empty on form submit using jQuery?

var save_val = $("form").serializeArray();
$(save_val).each(function( index, element ) {
    alert(element.name);
    alert(element.val);
});

Execute specified function every X seconds

The most beginner-friendly solution is:

Drag a Timer from the Toolbox, give it a Name, set your desired Interval, and set "Enabled" to True. Then double-click the Timer and Visual Studio (or whatever you are using) will write the following code for you:

private void wait_Tick(object sender, EventArgs e)
{
    refreshText(); // Add the method you want to call here.
}

No need to worry about pasting it into the wrong code block or something like that.

Java GC (Allocation Failure)

When use CMS GC in jdk1.8 will appeare this error, i change the G1 Gc solve this problem.

 -Xss512k -Xms6g -Xmx6g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=70 -XX:NewRatio=1 -XX:SurvivorRatio=6 -XX:G1ReservePercent=10 -XX:G1HeapRegionSize=32m -XX:ConcGCThreads=6 -Xloggc:gc.log -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCTimeStamps 

Laravel view not found exception

If your path to view is true first try to config:cache and route:cache if nothing changed check your resource path permission are true.

example: your can do it in ubuntu with :

sudo chgrp -R www-data resources/views
sudo usermod -a -G www-data $USER

Escaping double quotes in JavaScript onClick event handler

I think that the best approach is to assign the onclick handler unobtrusively.

Something like this:

window.onload = function(){
    var myLink = document.getElementsById('myLinkId');
    myLink.onclick = function(){ 
        parse('#', false, '<a href="xyz');
        return false;
    }
}

//...


<a href="#" id="myLink">Test</a>

Heroku deployment error H10 (App crashed)

See if you get

bash: bin/rails: No such file or directory

in logs while running (heroku logs -t) command if yes then please Run

bundle exec rake rails:update

Don't overwrite your files, in the end this command will create

  create  bin
  create  bin/bundle
  create  bin/rails
  create  bin/rake

push these files to heroku and you are done.

Send file using POST from a Python script

def visit_v2(device_code, camera_code):
    image1 = MultipartParam.from_file("files", "/home/yuzx/1.txt")
    image2 = MultipartParam.from_file("files", "/home/yuzx/2.txt")
    datagen, headers = multipart_encode([('device_code', device_code), ('position', 3), ('person_data', person_data), image1, image2])
    print "".join(datagen)
    if server_port == 80:
        port_str = ""
    else:
        port_str = ":%s" % (server_port,)
    url_str = "http://" + server_ip + port_str + "/adopen/device/visit_v2"
    headers['nothing'] = 'nothing'
    request = urllib2.Request(url_str, datagen, headers)
    try:
        response = urllib2.urlopen(request)
        resp = response.read()
        print "http_status =", response.code
        result = json.loads(resp)
        print resp
        return result
    except urllib2.HTTPError, e:
        print "http_status =", e.code
        print e.read()

How to vertically center content with variable height within a div?

Using the child selector, I've taken Fadi's incredible answer above and boiled it down to just one CSS rule that I can apply. Now all I have to do is add the contentCentered class name to elements I want to center:

_x000D_
_x000D_
.contentCentered {_x000D_
  text-align: center;_x000D_
}_x000D_
_x000D_
.contentCentered::before {_x000D_
  content: '';_x000D_
  display: inline-block;_x000D_
  height: 100%; _x000D_
  vertical-align: middle;_x000D_
  margin-right: -.25em; /* Adjusts for spacing */_x000D_
}_x000D_
_x000D_
.contentCentered > * {_x000D_
  display: inline-block;_x000D_
  vertical-align: middle;_x000D_
}
_x000D_
<div class="contentCentered">_x000D_
  <div>_x000D_
    <h1>Some text</h1>_x000D_
    <p>But he stole up to us again, and suddenly clapping his hand on my_x000D_
      shoulder, said&mdash;"Did ye see anything looking like men going_x000D_
      towards that ship a while ago?"</p>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Forked CodePen: http://codepen.io/dougli/pen/Eeysg

Remove HTML tags from a String

I know this is old, but I was just working on a project that required me to filter HTML and this worked fine:

noHTMLString.replaceAll("\\&.*?\\;", "");

instead of this:

html = html.replaceAll("&nbsp;","");
html = html.replaceAll("&amp;"."");

Select n random rows from SQL Server table

This is a combination of the initial seed idea and a checksum, which looks to me to give properly random results without the cost of NEWID():

SELECT TOP [number] 
FROM table_name
ORDER BY RAND(CHECKSUM(*) * RAND())

Install opencv for Python 3.3

EDIT: first try the new pip method:

Windows: pip3 install opencv-python opencv-contrib-python

Ubuntu: sudo apt install python3-opencv

or continue below for build instructions

Note: The original question was asking for OpenCV + Python 3.3 + Windows. Since then, Python 3.5 has been released. In addition, I use Ubuntu for most development so this answer will focus on that setup, unfortunately

OpenCV 3.1.0 + Python 3.5.2 + Ubuntu 16.04 is possible! Here's how.

These steps are copied (and slightly modified) from:

Prerequisites

Install the required dependencies and optionally install/update some libraries on your system:

# Required dependencies
sudo apt install build-essential cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
# Dependencies for Python bindings
# If you use a non-system copy of Python (eg. with pyenv or virtualenv), then you probably don't need to do this part
sudo apt install python3.5-dev libpython3-dev python3-numpy
# Optional, but installing these will ensure you have the latest versions compiled with OpenCV
sudo apt install libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev

Building OpenCV

CMake Flags

There are several flags and options to tweak your build of OpenCV. There might be comprehensive documentation about them, but here are some interesting flags that may be of use. They should be included in the cmake command:

# Builds in TBB, a threading library
-D WITH_TBB=ON
# Builds in Eigen, a linear algebra library
-D WITH_EIGEN=ON

Using non-system level Python versions

If you have multiple versions of Python (eg. from using pyenv or virtualenv), then you may want to build against a certain Python version. By default OpenCV will build for the system's version of Python. You can change this by adding these arguments to the cmake command seen later in the script. Actual values will depend on your setup. I use pyenv:

-D PYTHON_DEFAULT_EXECUTABLE=$HOME/.pyenv/versions/3.5.2/bin/python3.5
-D PYTHON_INCLUDE_DIRS=$HOME/.pyenv/versions/3.5.2/include/python3.5m
-D PYTHON_EXECUTABLE=$HOME/.pyenv/versions/3.5.2/bin/python3.5
-D PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so.1

CMake Python error messages

The CMakeLists file will try to detect various versions of Python to build for. If you've got different versions here, it might get confused. The above arguments may only "fix" the issue for one version of Python but not the other. If you only care about that specific version, then there's nothing else to worry about.

This is the case for me so unfortunately, I haven't looked into how to resolve the issues with other Python versions.

Install script

# Clone OpenCV somewhere
# I'll put it into $HOME/code/opencv
OPENCV_DIR="$HOME/code/opencv"
OPENCV_VER="3.1.0"
git clone https://github.com/opencv/opencv "$OPENCV_DIR"
# This'll take a while...

# Now lets checkout the specific version we want
cd "$OPENCV_DIR"
git checkout "$OPENCV_VER"

# First OpenCV will generate the files needed to do the actual build.
# We'll put them in an output directory, in this case "release"
mkdir release
cd release

# Note: This is where you'd add build options, like TBB support or custom Python versions. See above sections.
cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local "$OPENCV_DIR"

# At this point, take a look at the console output.
# OpenCV will print a report of modules and features that it can and can't support based on your system and installed libraries.
# The key here is to make sure it's not missing anything you'll need!
# If something's missing, then you'll need to install those dependencies and rerun the cmake command.

# OK, lets actually build this thing!
# Note: You can use the "make -jN" command, which will run N parallel jobs to speed up your build. Set N to whatever your machine can handle (usually <= the number of concurrent threads your CPU can run).
make
# This will also take a while...

# Now install the binaries!
sudo make install

By default, the install script will put the Python bindings in some system location, even if you've specified a custom version of Python to use. The fix is simple: Put a symlink to the bindings in your local site-packages:

ln -s /usr/local/lib/python3.5/site-packages/cv2.cpython-35m-x86_64-linux-gnu.so $HOME/.pyenv/versions/3.5.2/lib/python3.5/site-packages/

The first path will depend on the Python version you setup to build. The second depends on where your custom version of Python is located.

Test it!

OK lets try it out!

ipython

Python 3.5.2 (default, Sep 24 2016, 13:13:17) 
Type "copyright", "credits" or "license" for more information.

IPython 5.1.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: import cv2

In [2]: img = cv2.imread('derp.png')
i
In [3]: img[0]
Out[3]: 
array([[26, 30, 31],
       [27, 31, 32],
       [27, 31, 32],
       ..., 
       [16, 19, 20],
       [16, 19, 20],
       [16, 19, 20]], dtype=uint8)

Javascript form validation with password confirming

 if ($("#Password").val() != $("#ConfirmPassword").val()) {
          alert("Passwords do not match.");
      }

A JQuery approach that will eliminate needless code.

Extend a java class from one file in another java file

Just put the two files in the same directory. Here's an example:

Person.java

public class Person {
  public String name;

  public Person(String name) {
    this.name = name;
  }

  public String toString() {
    return name;
  }
}

Student.java

public class Student extends Person {
  public String somethingnew;

  public Student(String name) {
    super(name);
    somethingnew = "surprise!";
  }

  public String toString() {
    return super.toString() + "\t" + somethingnew;
  }

  public static void main(String[] args) {
    Person you = new Person("foo");
    Student me = new Student("boo");

    System.out.println("Your name is " + you);
    System.out.println("My name is " + me);
  }
}

Running Student (since it has the main function) yields us the desired outcome:

Your name is foo
My name is boo  surprise!

How to use if statements in LESS

I stumbled over the same question and I've found a solution.

First make sure you upgrade to LESS 1.6 at least. You can use npm for that case.

Now you can use the following mixin:

.if (@condition, @property, @value) when (@condition = true){
     @{property}: @value;
 }

Since LESS 1.6 you are able to pass PropertyNames to Mixins as well. So for example you could just use:

.myHeadline {
   .if(@include-lineHeight,  line-height, '35px');
}

If @include-lineheight resolves to true LESS will print the line-height: 35px and it will skip the mixin if @include-lineheight is not true.

What's the difference between 'r+' and 'a+' when open file in python?

Python opens files almost in the same way as in C:

  • r+ Open for reading and writing. The stream is positioned at the beginning of the file.

  • a+ Open for reading and appending (writing at end of file). The file is created if it does not exist. The initial file position for reading is at the beginning of the file, but output is appended to the end of the file (but in some Unix systems regardless of the current seek position).

Why Anaconda does not recognize conda command?

Got same issue and it turns out that besides setting PATH variable, I also should not close some cmd window poped up during installation. Re-installation would work

How do I request a file but not save it with Wget?

You can use -O- (uppercase o) to redirect content to the stdout (standard output) or to a file (even special files like /dev/null /dev/stderr /dev/stdout )

wget -O- http://yourdomain.com

Or:

wget -O- http://yourdomain.com > /dev/null

Or: (same result as last command)

wget -O/dev/null http://yourdomain.com

Angular cli generate a service and include the provider in one step

Angular 6+ Singleton Services

The recommended approach for a singleton service for Angular 6 and beyond is :

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class UserService {
}

In fact the CLI --module switch doesn't even exist any more for registering a service at the app level because it doesn't need to modify app.module.ts anymore.

This will create the above code, without needing to specify a module.

ng g s services/user

So if you don't want your service to be a singleton you must remove the providedIn code yourself - and then add it manually to providers for a component or lazy loaded module. Doesn't look like there is currently a switch to not generate the providedIn: 'root' part so you need to manually remove it.

How to build a JSON array from mysql database

Just an update for Mysqli users :

$base= mysqli_connect($dbhost,  $dbuser, $dbpass, $dbbase);

if (mysqli_connect_errno()) 
  die('Could not connect: ' . mysql_error());

$return_arr = array();

if ($result = mysqli_query( $base, $sql )){
    while ($row = mysqli_fetch_assoc($result)) {
    $row_array['id'] = $row['id'];
    $row_array['col1'] = $row['col1'];
    $row_array['col2'] = $row['col2'];

    array_push($return_arr,$row_array);
   }
 }

mysqli_close($base);

echo json_encode($return_arr);

Testing whether a value is odd or even

Use modulus:

function isEven(n) {
   return n % 2 == 0;
}

function isOdd(n) {
   return Math.abs(n % 2) == 1;
}

You can check that any value in Javascript can be coerced to a number with:

Number.isFinite(parseFloat(n))

This check should preferably be done outside the isEven and isOdd functions, so you don't have to duplicate error handling in both functions.

Check if a time is between two times (time DataType)

Let us consider a table which stores the shift details

enter image description here

Please check the SQL queries to generate table and finding the schedule based on an input(time)

Declaring the Table variable

declare @MyShiftTable table(MyShift int,StartTime time,EndTime time)

Adding values to Table variable

insert into @MyShiftTable select 1,'01:17:40.3530000','02:17:40.3530000'
insert into @MyShiftTable select 2,'09:17:40.3530000','03:17:40.3530000'
insert into @MyShiftTable select 3,'10:17:40.3530000','18:17:40.3530000'

Creating another table variable with an additional field named "Flag"

declare @Temp table(MyShift int,StartTime time,EndTime time,Flag int)

Adding values to temporary table with swapping the start and end time

insert into @Temp select MyShift,case when (StartTime>EndTime) then EndTime else StartTime end,case when (StartTime>EndTime) then StartTime else EndTime end,case when (StartTime>EndTime) then 1 else 0 end from @MyShiftTable

Creating input variable to find the Shift

declare @time time=convert(time,'10:12:40.3530000')

Query to find the shift corresponding to the time supplied

select myShift from @Temp where
(@time between StartTime and EndTime and Flag=0) or (@time not between StartTime and EndTime and Flag=1)

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

I'm not sure what you're looking for exactly, but you really should check out these excellent blog posts written by Chris Coyier from CSS-Tricks:

http://css-tricks.com/how-to-resizeable-background-image/

http://css-tricks.com/perfect-full-page-background-image/

Read the descriptions for each of the articles and see if they're what you're looking for.

The first answers the following question:

Is there a way to make a background image resizeable? As in, fill the background of a web page edge-to-edge with an image, no matter the size of the browser window. Also, have it resize larger or smaller as the browser window changes. Also, make sure it retains its ratio (doesn't stretch weird). Also, doesn't cause scrollbars, just cuts off vertically if it needs to. Also, comes in on the page as an inline tag.

The second post's goal is to get the following, a "background image on a website that covers the entire browser window at all times. "

Hope this helps.

Where is the .NET Framework 4.5 directory?

The webpage is incorrect and I have pointed this out to MS and they will get it changed.

As already stated above .NET 4.5 is an in-place upgrade of 4.0 so you will only have Microsoft.NET\Framework\v4.0.30319.

The ToolVersion for MSBuild remains at "4.0".

Call Stored Procedure within Create Trigger in SQL Server

finally...

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON

GO
ALTER TRIGGER [dbo].[RA2Newsletter] 
   ON  [dbo].[Reiseagent] 
   AFTER INSERT
 AS
    declare
    @rAgent_Name nvarchar(50),
    @rAgent_Email nvarchar(50),
    @rAgent_IP nvarchar(50),
    @hotelID int,
    @retval int


BEGIN
    SET NOCOUNT ON;

    -- Insert statements for trigger here
    Select @rAgent_Name=rAgent_Name,@rAgent_Email=rAgent_Email,@rAgent_IP=rAgent_IP,@hotelID=hotelID  From Inserted
    EXEC insert2Newsletter '','',@rAgent_Name,@rAgent_Email,@rAgent_IP,@hotelID,'RA', @retval

END

What is the best way to implement constants in Java?

I wouldn't call the class the same (aside from casing) as the constant ... I would have at a minimum one class of "Settings", or "Values", or "Constants", where all the constants would live. If I have a large number of them, I'd group them up in logical constant classes (UserSettings, AppSettings, etc.)

XPath with multiple conditions

Use:

/category[@name='Sport' and author/text()[1]='James Small']

or use:

/category[@name='Sport' and author[starts-with(.,'James Small')]]

It is a good rule to try to avoid using the // pseudo-operator whenever possible, because its evaluation can typically be very slow.

Also:

./somename

is equivalent to:

somename

so it is recommended to use the latter.

MySQL Select last 7 days

Since you are using an INNER JOIN you can just put the conditions in the WHERE clause, like this:

SELECT 
    p1.kArtikel, 
    p1.cName, 
    p1.cKurzBeschreibung, 
    p1.dLetzteAktualisierung, 
    p1.dErstellt, 
    p1.cSeo,
    p2.kartikelpict,
    p2.nNr,
    p2.cPfad  
FROM 
    tartikel AS p1 INNER JOIN tartikelpict AS p2 
    ON p1.kArtikel = p2.kArtikel
WHERE
  DATE(dErstellt) > (NOW() - INTERVAL 7 DAY)
  AND p2.nNr = 1
ORDER BY 
  p1.kArtikel DESC
LIMIT
    100;

Break or return from Java 8 stream forEach?

If you need this, you shouldn't use forEach, but one of the other methods available on streams; which one, depends on what your goal is.

For example, if the goal of this loop is to find the first element which matches some predicate:

Optional<SomeObject> result =
    someObjects.stream().filter(obj -> some_condition_met).findFirst();

(Note: This will not iterate the whole collection, because streams are lazily evaluated - it will stop at the first object that matches the condition).

If you just want to know if there's an element in the collection for which the condition is true, you could use anyMatch:

boolean result = someObjects.stream().anyMatch(obj -> some_condition_met);

How to add Active Directory user group as login in SQL Server

You can use T-SQL:

use master
GO
CREATE LOGIN [NT AUTHORITY\LOCALSERVICE] FROM WINDOWS WITH
DEFAULT_DATABASE=yourDbName
GO
CREATE LOGIN [NT AUTHORITY\NETWORKSERVICE] FROM WINDOWS WITH
DEFAULT_DATABASE=yourDbName

I use this as a part of restore from production server to testing machine:

USE master
GO
ALTER DATABASE yourDbName SET OFFLINE WITH ROLLBACK IMMEDIATE
RESTORE DATABASE yourDbName FROM DISK = 'd:\DropBox\backup\myDB.bak'
ALTER DATABASE yourDbName SET ONLINE
GO
CREATE LOGIN [NT AUTHORITY\LOCALSERVICE] FROM WINDOWS WITH
DEFAULT_DATABASE=yourDbName
GO
CREATE LOGIN [NT AUTHORITY\NETWORKSERVICE] FROM WINDOWS WITH
DEFAULT_DATABASE=yourDbName
GO

You will need to use localized name of services in case of German or French Windows, see How to create a SQL Server login for a service account on a non-English Windows?

PHP Curl And Cookies

First create temporary cookie using tempnam() function:

$ckfile = tempnam ("/tmp", "CURLCOOKIE");

Then execute curl init witch saves the cookie as a temporary file:

$ch = curl_init ("http://uri.com/");
curl_setopt ($ch, CURLOPT_COOKIEJAR, $ckfile);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, true);
$output = curl_exec ($ch);

Or visit a page using the cookie stored in the temporary file:

$ch = curl_init ("http://somedomain.com/cookiepage.php");
curl_setopt ($ch, CURLOPT_COOKIEFILE, $ckfile);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, true);
$output = curl_exec ($ch);

This will initialize the cookie for the page:

curl_setopt ($ch, CURLOPT_COOKIEFILE, $ckfile);

how to convert numeric to nvarchar in sql command

If the culture of the result doesn't matters or we're only talking of integer values, CONVERT or CAST will be fine.

However, if the result must match a specific culture, FORMAT might be the function to go:

DECLARE @value DECIMAL(19,4) = 1505.5698
SELECT CONVERT(NVARCHAR, @value)        -->  1505.5698
SELECT FORMAT(@value, 'N2', 'en-us')    --> 1,505.57
SELECT FORMAT(@value, 'N2', 'de-de')    --> 1.505,57

For more information on FORMAT see here.

Of course, formatting the result should be a matter of the UI layer of the software.

Check if date is a valid one

Here you go: Working Fidddle

$(function(){
  var dateFormat = 'DD-MM-YYYY';
  alert(moment(moment("2012-10-19").format(dateFormat),dateFormat,true).isValid());
});

How to install Intellij IDEA on Ubuntu?

I needed to install various JetBrains tools on a number of machines from CLI, so I wrote a tiny tool to help with that. It also uses cleaner APIs from JB making it hopefully more stable, and works for various JB tools.

Feel free to try it: https://github.com/MarcinZukowski/jetbrains-installer

Does 'position: absolute' conflict with Flexbox?

No, absolutely positioning does not conflict with flex containers. Making an element be a flex container only affects its inner layout model, that is, the way in which its contents are laid out. Positioning affects the element itself, and can alter its outer role for flow layout.

That means that

  • If you add absolute positioning to an element with display: inline-flex, it will become block-level (like display: flex), but will still generate a flex formatting context.

  • If you add absolute positioning to an element with display: flex, it will be sized using the shrink-to-fit algorithm (typical of inline-level containers) instead of the fill-available one.

That said, absolutely positioning conflicts with flex children.

As it is out-of-flow, an absolutely-positioned child of a flex container does not participate in flex layout.

How to convert DOS/Windows newline (CRLF) to Unix newline (LF) in a Bash script?

interestingly in my git-bash on windows sed "" did the trick already:

$ echo -e "abc\r" >tst.txt
$ file tst.txt
tst.txt: ASCII text, with CRLF line terminators
$ sed -i "" tst.txt
$ file tst.txt
tst.txt: ASCII text

My guess is that sed ignores them when reading lines from input and always writes unix line endings on output.

node: command not found

The problem is that your PATH does not include the location of the node executable.

You can likely run node as "/usr/local/bin/node".

You can add that location to your path by running the following command to add a single line to your bashrc file:

echo 'export PATH=$PATH:/usr/local/bin' >> $HOME/.bashrc

gnuplot : plotting data from multiple input files in a single graph

replot

This is another way to get multiple plots at once:

plot file1.data
replot file2.data

How to get certain commit from GitHub project

Sivan's answer in gif enter image description here

1.Click on commits in github

2.Select Browse code on the right side of each commit

3.Click on download zip , which will download source code at that point of time of commit

Can I pass an array as arguments to a method with variable arguments in Java?

Yes, a T... is only a syntactic sugar for a T[].

JLS 8.4.1 Format parameters

The last formal parameter in a list is special; it may be a variable arity parameter, indicated by an elipsis following the type.

If the last formal parameter is a variable arity parameter of type T, it is considered to define a formal parameter of type T[]. The method is then a variable arity method. Otherwise, it is a fixed arity method. Invocations of a variable arity method may contain more actual argument expressions than formal parameters. All the actual argument expressions that do not correspond to the formal parameters preceding the variable arity parameter will be evaluated and the results stored into an array that will be passed to the method invocation.

Here's an example to illustrate:

public static String ezFormat(Object... args) {
    String format = new String(new char[args.length])
        .replace("\0", "[ %s ]");
    return String.format(format, args);
}
public static void main(String... args) {
    System.out.println(ezFormat("A", "B", "C"));
    // prints "[ A ][ B ][ C ]"
}

And yes, the above main method is valid, because again, String... is just String[]. Also, because arrays are covariant, a String[] is an Object[], so you can also call ezFormat(args) either way.

See also


Varargs gotchas #1: passing null

How varargs are resolved is quite complicated, and sometimes it does things that may surprise you.

Consider this example:

static void count(Object... objs) {
    System.out.println(objs.length);
}

count(null, null, null); // prints "3"
count(null, null); // prints "2"
count(null); // throws java.lang.NullPointerException!!!

Due to how varargs are resolved, the last statement invokes with objs = null, which of course would cause NullPointerException with objs.length. If you want to give one null argument to a varargs parameter, you can do either of the following:

count(new Object[] { null }); // prints "1"
count((Object) null); // prints "1"

Related questions

The following is a sample of some of the questions people have asked when dealing with varargs:


Vararg gotchas #2: adding extra arguments

As you've found out, the following doesn't "work":

    String[] myArgs = { "A", "B", "C" };
    System.out.println(ezFormat(myArgs, "Z"));
    // prints "[ [Ljava.lang.String;@13c5982 ][ Z ]"

Because of the way varargs work, ezFormat actually gets 2 arguments, the first being a String[], the second being a String. If you're passing an array to varargs, and you want its elements to be recognized as individual arguments, and you also need to add an extra argument, then you have no choice but to create another array that accommodates the extra element.

Here are some useful helper methods:

static <T> T[] append(T[] arr, T lastElement) {
    final int N = arr.length;
    arr = java.util.Arrays.copyOf(arr, N+1);
    arr[N] = lastElement;
    return arr;
}
static <T> T[] prepend(T[] arr, T firstElement) {
    final int N = arr.length;
    arr = java.util.Arrays.copyOf(arr, N+1);
    System.arraycopy(arr, 0, arr, 1, N);
    arr[0] = firstElement;
    return arr;
}

Now you can do the following:

    String[] myArgs = { "A", "B", "C" };
    System.out.println(ezFormat(append(myArgs, "Z")));
    // prints "[ A ][ B ][ C ][ Z ]"

    System.out.println(ezFormat(prepend(myArgs, "Z")));
    // prints "[ Z ][ A ][ B ][ C ]"

Varargs gotchas #3: passing an array of primitives

It doesn't "work":

    int[] myNumbers = { 1, 2, 3 };
    System.out.println(ezFormat(myNumbers));
    // prints "[ [I@13c5982 ]"

Varargs only works with reference types. Autoboxing does not apply to array of primitives. The following works:

    Integer[] myNumbers = { 1, 2, 3 };
    System.out.println(ezFormat(myNumbers));
    // prints "[ 1 ][ 2 ][ 3 ]"

Differences between Html.TextboxFor and Html.EditorFor in MVC and Razor

TextBoxFor: It will render like text input html element corresponding to specified expression. In simple word it will always render like an input textbox irrespective datatype of the property which is getting bind with the control.

EditorFor: This control is bit smart. It renders HTML markup based on the datatype of the property. E.g. suppose there is a boolean property in model. To render this property in the view as a checkbox either we can use CheckBoxFor or EditorFor. Both will be generate the same markup.

What is the advantage of using EditorFor?

As we know, depending on the datatype of the property it generates the html markup. So suppose tomorrow if we change the datatype of property in the model, no need to change anything in the view. EditorFor control will change the html markup automatically.

Sort a Map<Key, Value> by values

Late Entry.

With the advent of Java-8, we can use streams for data manipulation in a very easy/succinct way. You can use streams to sort the map entries by value and create a LinkedHashMap which preserves insertion-order iteration.

Eg:

LinkedHashMap sortedByValueMap = map.entrySet().stream()
                .sorted(comparing(Entry<Key,Value>::getValue).thenComparing(Entry::getKey))     //first sorting by Value, then sorting by Key(entries with same value)
                .collect(LinkedHashMap::new,(map,entry) -> map.put(entry.getKey(),entry.getValue()),LinkedHashMap::putAll);

For reverse ordering, replace:

comparing(Entry<Key,Value>::getValue).thenComparing(Entry::getKey)

with

comparing(Entry<Key,Value>::getValue).thenComparing(Entry::getKey).reversed()

Webdriver Screenshot

Yes, we have a way to get screenshot extension of .png using python webdriver

use below code if you working in python webriver.it is very simple.

driver.save_screenshot('D\folder\filename.png')

How to return an array from a function?

It is not possible to return an array from a C++ function. 8.3.5[dcl.fct]/6:

Functions shall not have a return type of type array or function[...]

Most commonly chosen alternatives are to return a value of class type where that class contains an array, e.g.

struct ArrayHolder
{
    int array[10];
};

ArrayHolder test();

Or to return a pointer to the first element of a statically or dynamically allocated array, the documentation must indicate to the user whether he needs to (and if so how he should) deallocate the array that the returned pointer points to.

E.g.

int* test2()
{
    return new int[10];
}

int* test3()
{
    static int array[10];
    return array;
}

While it is possible to return a reference or a pointer to an array, it's exceedingly rare as it is a more complex syntax with no practical advantage over any of the above methods.

int (&test4())[10]
{
        static int array[10];
        return array;
}

int (*test5())[10]
{
        static int array[10];
        return &array;
}

Copying files from one directory to another in Java

You seem to be looking for the simple solution (a good thing). I recommend using Apache Common's FileUtils.copyDirectory:

Copies a whole directory to a new location preserving the file dates.

This method copies the specified directory and all its child directories and files to the specified destination. The destination is the new location and name of the directory.

The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

Your code could like nice and simple like this:

File trgDir = new File("/tmp/myTarget/");
File srcDir = new File("/tmp/mySource/");

FileUtils.copyDirectory(srcDir, trgDir);

Calculating number of full months between two dates in SQL

The original post had some bugs... so I re-wrote and packaged it as a UDF.

CREATE FUNCTION FullMonthsSeparation 
(
    @DateA DATETIME,
    @DateB DATETIME
)
RETURNS INT
AS
BEGIN
    DECLARE @Result INT

    DECLARE @DateX DATETIME
    DECLARE @DateY DATETIME

    IF(@DateA < @DateB)
    BEGIN
        SET @DateX = @DateA
        SET @DateY = @DateB
    END
    ELSE
    BEGIN
        SET @DateX = @DateB
        SET @DateY = @DateA
    END

    SET @Result = (
                    SELECT 
                    CASE 
                        WHEN DATEPART(DAY, @DateX) > DATEPART(DAY, @DateY)
                        THEN DATEDIFF(MONTH, @DateX, @DateY) - 1
                        ELSE DATEDIFF(MONTH, @DateX, @DateY)
                    END
                    )

    RETURN @Result
END
GO

SELECT dbo.FullMonthsSeparation('2009-04-16', '2009-05-15') as MonthSep -- =0
SELECT dbo.FullMonthsSeparation('2009-04-16', '2009-05-16') as MonthSep -- =1
SELECT dbo.FullMonthsSeparation('2009-04-16', '2009-06-16') as MonthSep -- =2

How do I generate a random integer between min and max in Java?

With Java 7 or above you could use

ThreadLocalRandom.current().nextInt(int origin, int bound)

Javadoc: ThreadLocalRandom.nextInt

How to make a GUI for bash scripts?

If you have Qt/KDE installed, you can use kdialog, which pops up a Qt dialog window. You can easily specify to display a Yes/No dialog, OK/Cancel, simple text input, password input etc. You then have access to the return values from these dialogs at the shell.

Java2D: Increase the line width

You should use setStroke to set a stroke of the Graphics2D object.

The example at http://www.java2s.com gives you some code examples.

The following code produces the image below:

import java.awt.*;
import java.awt.geom.Line2D;
import javax.swing.*;

public class FrameTest {
    public static void main(String[] args) {
        JFrame jf = new JFrame("Demo");
        Container cp = jf.getContentPane();
        cp.add(new JComponent() {
            public void paintComponent(Graphics g) {
                Graphics2D g2 = (Graphics2D) g;
                g2.setStroke(new BasicStroke(10));
                g2.draw(new Line2D.Float(30, 20, 80, 90));
            }
        });
        jf.setSize(300, 200);
        jf.setVisible(true);
    }
}

enter image description here

(Note that the setStroke method is not available in the Graphics object. You have to cast it to a Graphics2D object.)


This post has been rewritten as an article here.

How to use '-prune' option of 'find' in sh?

I am no expert at this (and this page was very helpful along with http://mywiki.wooledge.org/UsingFind)

Just noticed -path is for a path that fully matches the string/path that comes just after find (. in theses examples) where as -name matches all basenames.

find . -path ./.git  -prune -o -name file  -print

blocks the .git directory in your current directory ( as your finding in . )

find . -name .git  -prune -o -name file  -print

blocks all .git subdirectories recursively.

Note the ./ is extremely important!! -path must match a path anchored to . or whatever comes just after find if you get matches with out it (from the other side of the or '-o') there probably not being pruned! I was naively unaware of this and it put me of using -path when it is great when you don't want to prune all subdirectory with the same basename :D

How to clear the entire array?

Only use Redim statement

 Dim aFirstArray() As Variant

Redim aFirstArray(nRows,nColumns)

Apply Calibri (Body) font to text

There is no such font as “Calibri (Body)”. You probably saw this string in Microsoft Word font selection menu, but it’s not a font name (see e.g. the explanation Font: +body (in W07)).

So use just font-family: Calibri or, better, font-family: Calibri, sans-serif. (There is no adequate backup font for Calibri, but the odds are that when Calibri is not available, the browser’s default sans-serif font suits your design better than the browser’s default font, which is most often a serif font.)

How to make a custom LinkedIn share button

LinkedIn revised their site recently, so there are a ton of old links just redirecting to the developer support homepage. Here is an updated link to the relevant page on LinkedIn's support site (as of Feb 16, 2015): https://developer.linkedin.com/docs/share-on-linkedin

What is size_t in C?

size_t is a type that can hold any array index.

Depending on the implementation, it can be any of:

unsigned char

unsigned short

unsigned int

unsigned long

unsigned long long

Here's how size_t is defined in stddef.h of my machine:

typedef unsigned long size_t;

How to get base URL in Web API controller?

You could use VirtualPathRoot property from HttpRequestContext (request.GetRequestContext().VirtualPathRoot)

How to check Elasticsearch cluster health?

PROBLEM :-

Sometimes, Localhost may not get resolved. So it tends to return an output as seen below :

# curl -XGET localhost:9200/_cluster/health?pretty

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html><head>
<meta http-equiv="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<title>ERROR: The requested URL could not be retrieved</title>
<style type="text/css"><!--BODY{background-color:#ffffff;font-family:verdana,sans-serif}PRE{font-family:sans-serif}--></style>
</head><body>
<h1>ERROR</h1>
<h2>The requested URL could not be retrieved</h2>
<hr>
<p>The following error was encountered while trying to retrieve the URL: <a href="http://localhost:9200/_cluster/health?">http://localhost:9200/_cluster/health?</a></p>
<blockquote>
<p><b>Connection to 127.0.0.1 failed.</b></p>
</blockquote>

<p>The system returned: <i>(111) Connection refused</i></p>

<p>The remote host or network may be down.  Please try the request again.</p>
<p>Your cache administrator is <a href="mailto:root?subject=CacheErrorInfo%20-%20ERR_CONNECT_FAIL&amp;body=CacheHost%3A%20squid2%0D%0AErrPage%3A%20ERR_CONNECT_FAIL%0D%0AErr%3A%20(111)%20Connection%20refused%0D%0ATimeStamp%3A%20Mon,%2017%20Dec%202018%2008%3A07%3A36%20GMT%0D%0A%0D%0AClientIP%3A%20192.168.13.14%0D%0AServerIP%3A%20127.0.0.1%0D%0A%0D%0AHTTP%20Request%3A%0D%0AGET%20%2F_cluster%2Fhealth%3Fpretty%20HTTP%2F1.1%0AUser-Agent%3A%20curl%2F7.29.0%0D%0AHost%3A%20localhost%3A9200%0D%0AAccept%3A%20*%2F*%0D%0AProxy-Connection%3A%20Keep-Alive%0D%0A%0D%0A%0D%0A">root</a>.</p>

<br>   
<hr> 
<div id="footer">Generated Mon, 17 Dec 2018 08:07:36 GMT by squid2 (squid/3.0.STABLE25)</div>
</body></html>

# curl -XGET localhost:9200/_cat/indices

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html><head>
<meta http-equiv="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<title>ERROR: The requested URL could not be retrieved</title>
<style type="text/css"><!--BODY{background-color:#ffffff;font-family:verdana,sans-serif}PRE{font-family:sans-serif}--></style>
</head><body>
<h1>ERROR</h1>
<h2>The requested URL could not be retrieved</h2>
<hr>
<p>The following error was encountered while trying to retrieve the URL: <a href="http://localhost:9200/_cat/indices">http://localhost:9200/_cat/indices</a></p>
<blockquote>
<p><b>Connection to 127.0.0.1 failed.</b></p>
</blockquote>

<p>The system returned: <i>(111) Connection refused</i></p>

<p>The remote host or network may be down.  Please try the request again.</p>
<p>Your cache administrator is <a href="mailto:root?subject=CacheErrorInfo%20-%20ERR_CONNECT_FAIL&amp;body=CacheHost%3A%20squid2%0D%0AErrPage%3A%20ERR_CONNECT_FAIL%0D%0AErr%3A%20(111)%20Connection%20refused%0D%0ATimeStamp%3A%20Mon,%2017%20Dec%202018%2008%3A10%3A09%20GMT%0D%0A%0D%0AClientIP%3A%20192.168.13.14%0D%0AServerIP%3A%20127.0.0.1%0D%0A%0D%0AHTTP%20Request%3A%0D%0AGET%20%2F_cat%2Findices%20HTTP%2F1.1%0AUser-Agent%3A%20curl%2F7.29.0%0D%0AHost%3A%20localhost%3A9200%0D%0AAccept%3A%20*%2F*%0D%0AProxy-Connection%3A%20Keep-Alive%0D%0A%0D%0A%0D%0A">root</a>.</p>

<br>   
<hr> 
<div id="footer">Generated Mon, 17 Dec 2018 08:10:09 GMT by squid2 (squid/3.0.STABLE25)</div>
</body></html>

SOLUTION :-

Guess, this error is most probably returned by Local Squid deployed in the server.

So, it worked fine and good after replacing localhost by the local_ip in which the ElasticSearch has been deployed.

What do hjust and vjust do when making a plot using ggplot?

Probably the most definitive is Figure B.1(d) of the ggplot2 book, the appendices of which are available at http://ggplot2.org/book/appendices.pdf.

enter image description here

However, it is not quite that simple. hjust and vjust as described there are how it works in geom_text and theme_text (sometimes). One way to think of it is to think of a box around the text, and where the reference point is in relation to that box, in units relative to the size of the box (and thus different for texts of different size). An hjust of 0.5 and a vjust of 0.5 center the box on the reference point. Reducing hjust moves the box right by an amount of the box width times 0.5-hjust. Thus when hjust=0, the left edge of the box is at the reference point. Increasing hjust moves the box left by an amount of the box width times hjust-0.5. When hjust=1, the box is moved half a box width left from centered, which puts the right edge on the reference point. If hjust=2, the right edge of the box is a box width left of the reference point (center is 2-0.5=1.5 box widths left of the reference point. For vertical, less is up and more is down. This is effectively what that Figure B.1(d) says, but it extrapolates beyond [0,1].

But, sometimes this doesn't work. For example

DF <- data.frame(x=c("a","b","cdefghijk","l"),y=1:4)
p <- ggplot(DF, aes(x,y)) + geom_point()

p + opts(axis.text.x=theme_text(vjust=0))
p + opts(axis.text.x=theme_text(vjust=1))
p + opts(axis.text.x=theme_text(vjust=2))

The three latter plots are identical. I don't know why that is. Also, if text is rotated, then it is more complicated. Consider

p + opts(axis.text.x=theme_text(hjust=0, angle=90))
p + opts(axis.text.x=theme_text(hjust=0.5 angle=90))
p + opts(axis.text.x=theme_text(hjust=1, angle=90))
p + opts(axis.text.x=theme_text(hjust=2, angle=90))

The first has the labels left justified (against the bottom), the second has them centered in some box so their centers line up, and the third has them right justified (so their right sides line up next to the axis). The last one, well, I can't explain in a coherent way. It has something to do with the size of the text, the size of the widest text, and I'm not sure what else.

Using BigDecimal to work with currencies

1) If you are limited to the double precision, one reason to use BigDecimals is to realize operations with the BigDecimals created from the doubles.

2) The BigDecimal consists of an arbitrary precision integer unscaled value and a non-negative 32-bit integer scale, while the double wraps a value of the primitive type double in an object. An object of type Double contains a single field whose type is double

3) It should make no difference

You should have no difficulties with the $ and precision. One way to do it is using System.out.printf

How to pass payload via JSON file for curl?

curl sends POST requests with the default content type of application/x-www-form-urlencoded. If you want to send a JSON request, you will have to specify the correct content type header:

$ curl -vX POST http://server/api/v1/places.json -d @testplace.json \
--header "Content-Type: application/json"

But that will only work if the server accepts json input. The .json at the end of the url may only indicate that the output is json, it doesn't necessarily mean that it also will handle json input. The API documentation should give you a hint on whether it does or not.

The reason you get a 401 and not some other error is probably because the server can't extract the auth_token from your request.

How to return a value from a Form in C#?

I just put into constructor something by reference, so the subform can change its value and main form can get new or modified object from subform.

How to handle checkboxes in ASP.NET MVC forms?

When using the checkbox HtmlHelper, I much prefer to work with the posted checkbox form data as an array. I don't really know why, I know the other methods work, but I think I just prefer to treat comma separated strings as an array as much as possible.

So doing a 'checked' or true test would be:

//looking for [true],[false]
bool isChecked = form.GetValues(key).Contains("true"); 

Doing a false check would be:

//looking for [false],[false] or [false]
bool isNotChecked = !form.GetValues(key).Contains("true"); 

The main difference is to use GetValues as this returns as an array.

Access Control Origin Header error using Axios in React Web throwing error in Chrome

$ npm install cors

After installing cors from npm add the code below to your node app file. It solved my problem.

var express = require('express')
var cors = require('cors')
var app = express()

app.use(cors())

Reading a date using DataReader

Try as given below:

while (MyReader.Read())
{
    TextBox1.Text = Convert.ToDateTime(MyReader["DateField"]).ToString("dd/MM/yyyy");
}

in ToString() method you can change data format as per your requirement.

Insert data into hive table

Try to use this with single quotes in data:

insert into table test_hive values ('1','puneet');

How to fix HTTP 404 on Github Pages?

Four months ago I have contacted the support and they told me it was a problem on their side, they have temporarily fix it (for the current commit).

Today I tried again

  1. I deleted the gh-pages branch on github

    git push origin --delete gh-pages

  2. I deleted the gh-pages branch on local

    git branch -D gh-pages

  3. I reinitialized git

    git init

  4. I recreated the branch on local

    git branch gh-pages

  5. I pushed the gh-pages branch to github

    git push origin gh-pages

Works fine, I can finally update my files on the page.

How do I use reflection to invoke a private method?

I think you can pass it BindingFlags.NonPublic where it is the GetMethod method.

Is there any pythonic way to combine two dicts (adding values for keys that appear in both)?

Merging three dicts a,b,c in a single line without any other modules or libs

If we have the three dicts

a = {"a":9}
b = {"b":7}
c = {'b': 2, 'd': 90}

Merge all with a single line and return a dict object using

c = dict(a.items() + b.items() + c.items())

Returning

{'a': 9, 'b': 2, 'd': 90}

PowerMockito mock single static method and return object

What you want to do is a combination of part of 1 and all of 2.

You need to use the PowerMockito.mockStatic to enable static mocking for all static methods of a class. This means make it possible to stub them using the when-thenReturn syntax.

But the 2-argument overload of mockStatic you are using supplies a default strategy for what Mockito/PowerMock should do when you call a method you haven't explicitly stubbed on the mock instance.

From the javadoc:

Creates class mock with a specified strategy for its answers to interactions. It's quite advanced feature and typically you don't need it to write decent tests. However it can be helpful when working with legacy systems. It is the default answer so it will be used only when you don't stub the method call.

The default default stubbing strategy is to just return null, 0 or false for object, number and boolean valued methods. By using the 2-arg overload, you're saying "No, no, no, by default use this Answer subclass' answer method to get a default value. It returns a Long, so if you have static methods which return something incompatible with Long, there is a problem.

Instead, use the 1-arg version of mockStatic to enable stubbing of static methods, then use when-thenReturn to specify what to do for a particular method. For example:

import static org.mockito.Mockito.*;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

class ClassWithStatics {
  public static String getString() {
    return "String";
  }

  public static int getInt() {
    return 1;
  }
}

@RunWith(PowerMockRunner.class)
@PrepareForTest(ClassWithStatics.class)
public class StubJustOneStatic {
  @Test
  public void test() {
    PowerMockito.mockStatic(ClassWithStatics.class);

    when(ClassWithStatics.getString()).thenReturn("Hello!");

    System.out.println("String: " + ClassWithStatics.getString());
    System.out.println("Int: " + ClassWithStatics.getInt());
  }
}

The String-valued static method is stubbed to return "Hello!", while the int-valued static method uses the default stubbing, returning 0.

How to compile a 64-bit application using Visual C++ 2010 Express?

Download the Windows SDK and then go to View->Properties->Configuration Manager->Active Solution Platform->New->x64.

What are MVP and MVC and what is the difference?

MVP: the view is in charge.

The view, in most cases, creates its presenter. The presenter will interact with the model and manipulate the view through an interface. The view will sometimes interact with the presenter, usually through some interface. This comes down to implementation; do you want the view to call methods on the presenter or do you want the view to have events the presenter listens to? It boils down to this: The view knows about the presenter. The view delegates to the presenter.

MVC: the controller is in charge.

The controller is created or accessed based on some event/request. The controller then creates the appropriate view and interacts with the model to further configure the view. It boils down to: the controller creates and manages the view; the view is slave to the controller. The view does not know about the controller.

How to find and replace string?

Here's the version I ended up writing that replaces all instances of the target string in a given string. Works on any string type.

template <typename T, typename U>
T &replace (
          T &str, 
    const U &from, 
    const U &to)
{
    size_t pos;
    size_t offset = 0;
    const size_t increment = to.size();

    while ((pos = str.find(from, offset)) != T::npos)
    {
        str.replace(pos, from.size(), to);
        offset = pos + increment;
    }

    return str;
}

Example:

auto foo = "this is a test"s;
replace(foo, "is"s, "wis"s);
cout << foo;

Output:

thwis wis a test

Note that even if the search string appears in the replacement string, this works correctly.

How do I compare if a string is not equal to?

Either != or ne will work, but you need to get the accessor syntax and nested quotes sorted out.

<c:if test="${content.contentType.name ne 'MCE'}">
    <%-- snip --%>
</c:if>

Initialising an array of fixed size in python

You can use:

>>> lst = [None] * 5
>>> lst
[None, None, None, None, None]

Close popup window

In my case, I just needed to close my pop-up and redirect the user to his profile page when he clicks "ok" after reading some message I tried with a few hacks, including setTimeout + self.close(), but with IE, this was closing the whole tab...

Solution : I replaced my link with a simple submit button.
<button type="submit" onclick="window.location.href='profile.html';">buttonText</button>. Nothing more.

This may sound stupid, but I didn't think to such a simple solution, since my pop-up did not have any form.

I hope it will help some front-end noobs like me !

What is the correct way to represent null XML elements?

The documentation in the w3 link

http://www.w3.org/TR/REC-xml/#sec-starttags

says that this are the recomended forms.

<test></test>
<test/>

The attribute mentioned in the other answer is validation mechanism and not a representation of state. Please refer to the http://www.w3.org/TR/xmlschema-1/#xsi_nil

XML Schema: Structures introduces a mechanism for signaling that an element should be accepted as ·valid· when it has no content despite a content type which does not require or even necessarily allow empty content. An element may be ·valid· without content if it has the attribute xsi:nil with the value true. An element so labeled must be empty, but can carry attributes if permitted by the corresponding complex type.

To clarify this answer: Content

  <Book>
    <!--Invalid construct since the element attribute xsi:nil="true" signal that the element must be empty-->
    <BuildAttributes HardCover="true" Glued="true" xsi:nil="true">
      <anotherAttribute name="Color">Blue</anotherAttribute>
    </BuildAttributes>
    <Index></Index>
    <pages>
      <page pageNumber="1">Content</page>            
    </pages>
    <!--Missing ISBN number could be confusing and misguiding since its not present-->
  </Book>
</Books>

How to run .sh on Windows Command Prompt?

Personally I used this batch file, but it does require CygWin installed (64-bit as shown). Just associate the file type .SH with this batchfile (ExecSH.BAT in my case) and you can double-click on the .SH and it runs.

@echo off
setlocal

if not exist "%~dpn1.sh" echo Script "%~dpn1.sh" not found & goto :eof

set _CYGBIN=C:\cygwin64\bin
if not exist "%_CYGBIN%" echo Couldn't find Cygwin at "%_CYGBIN%" & goto :eof

:: Resolve ___.sh to /cygdrive based *nix path and store in %_CYGSCRIPT%
for /f "delims=" %%A in ('%_CYGBIN%\cygpath.exe "%~dpn1.sh"') do set _CYGSCRIPT=%%A
for /f "delims=" %%A in ('%_CYGBIN%\cygpath.exe "%CD%"') do set _CYGPATH=%%A

:: Throw away temporary env vars and invoke script, passing any args that were passed to us
endlocal & %_CYGBIN%\mintty.exe -e /bin/bash -l -c 'cd %_CYGPATH%;  %_CYGSCRIPT% %*'

Based on this original work.

Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

First, knowing where the data directory was for me was the key. /usr/local/var/mysql In here, there was at least one file with extension .err preceded with my local machine name. It had all info i needed to diagnose.

I think i screwed up by installing mysql 8 first. My app isn't compatible with it so i had to downgrade back to 5.7

My solution that worked for me was going to /usr/local/etc/my.cnf

Find this line if its there. I think its mysql 8 related:

mysqlx-bind-address = 127.0.0.1 

Remove it because in the mysql 5.7 says it doesnt like it in the error log

Also add this line in there if its not there under the bind-address.

socket=/tmp/mysql.sock

Go to the /tmp directory and delete any mysql.sock files in there. On server start, it will recreate the sock files

Trash out the data directory with mySQL in the stopped state. Mine was /usr/local/var/mysql . This is the same place where the logs are at

From there i ran

>mysqld --initialize

Then everything started working...this command will give you a random password at the end. Save that password for the next step

Running this to assign my own password.

>mysql_secure_installation 

Both

>brew services stop [email protected]

and

>mysql.server start

are now working. Hope this helps. It's about 3 hours of trial and error.

In android app Toolbar.setTitle method has no effect – application name is shown as title

Simply you can change any activity name by using

Activityname.this.setTitle("Title Name");

How to check if a column exists before adding it to an existing table in PL/SQL?

Or, you can ignore the error:

declare
    column_exists exception;
    pragma exception_init (column_exists , -01430);
begin
    execute immediate 'ALTER TABLE db.tablename ADD columnname NVARCHAR2(30)';
    exception when column_exists then null;
end;
/

How to unzip a file in Powershell?

For those, who want to use Shell.Application.Namespace.Folder.CopyHere() and want to hide progress bars while copying, or use more options, the documentation is here:
https://docs.microsoft.com/en-us/windows/desktop/shell/folder-copyhere

To use powershell and hide progress bars and disable confirmations you can use code like this:

# We should create folder before using it for shell operations as it is required
New-Item -ItemType directory -Path "C:\destinationDir" -Force

$shell = New-Object -ComObject Shell.Application
$zip = $shell.Namespace("C:\archive.zip")
$items = $zip.items()
$shell.Namespace("C:\destinationDir").CopyHere($items, 1556)

Limitations of use of Shell.Application on windows core versions:
https://docs.microsoft.com/en-us/windows-server/administration/server-core/what-is-server-core

On windows core versions, by default the Microsoft-Windows-Server-Shell-Package is not installed, so shell.applicaton will not work.

note: Extracting archives this way will take a long time and can slow down windows gui

Difference between AutoPostBack=True and AutoPostBack=False?

The AutoPostBack property is used to set or return whether or not an automatic post back occurs when the user presses "ENTER" or "TAB" in the TextBox control.

If this property is set to TRUE the automatic post back is enabled, otherwise FALSE. Default is FALSE.

ECMAScript 6 class destructor

You have to manually "destruct" objects in JS. Creating a destroy function is common in JS. In other languages this might be called free, release, dispose, close, etc. In my experience though it tends to be destroy which will unhook internal references, events and possibly propagates destroy calls to child objects as well.

WeakMaps are largely useless as they cannot be iterated and this probably wont be available until ECMA 7 if at all. All WeakMaps let you do is have invisible properties detached from the object itself except for lookup by the object reference and GC so that they don't disturb it. This can be useful for caching, extending and dealing with plurality but it doesn't really help with memory management for observables and observers. WeakSet is a subset of WeakMap (like a WeakMap with a default value of boolean true).

There are various arguments on whether to use various implementations of weak references for this or destructors. Both have potential problems and destructors are more limited.

Destructors are actually potentially useless for observers/listeners as well because typically the listener will hold references to the observer either directly or indirectly. A destructor only really works in a proxy fashion without weak references. If your Observer is really just a proxy taking something else's Listeners and putting them on an observable then it can do something there but this sort of thing is rarely useful. Destructors are more for IO related things or doing things outside of the scope of containment (IE, linking up two instances that it created).

The specific case that I started looking into this for is because I have class A instance that takes class B in the constructor, then creates class C instance which listens to B. I always keep the B instance around somewhere high above. A I sometimes throw away, create new ones, create many, etc. In this situation a Destructor would actually work for me but with a nasty side effect that in the parent if I passed the C instance around but removed all A references then the C and B binding would be broken (C has the ground removed from beneath it).

In JS having no automatic solution is painful but I don't think it's easily solvable. Consider these classes (pseudo):

function Filter(stream) {
    stream.on('data', function() {
        this.emit('data', data.toString().replace('somenoise', '')); // Pretend chunks/multibyte are not a problem.
    });
}
Filter.prototype.__proto__ = EventEmitter.prototype;
function View(df, stream) {
    df.on('data', function(data) {
        stream.write(data.toUpper()); // Shout.
    });
}

On a side note, it's hard to make things work without anonymous/unique functions which will be covered later.

In a normal case instantiation would be as so (pseudo):

var df = new Filter(stdin),
    v1 = new View(df, stdout),
    v2 = new View(df, stderr);

To GC these normally you would set them to null but it wont work because they've created a tree with stdin at the root. This is basically what event systems do. You give a parent to a child, the child adds itself to the parent and then may or may not maintain a reference to the parent. A tree is a simple example but in reality you may also find yourself with complex graphs albeit rarely.

In this case, Filter adds a reference to itself to stdin in the form of an anonymous function which indirectly references Filter by scope. Scope references are something to be aware of and that can be quite complex. A powerful GC can do some interesting things to carve away at items in scope variables but that's another topic. What is critical to understand is that when you create an anonymous function and add it to something as a listener to ab observable, the observable will maintain a reference to the function and anything the function references in the scopes above it (that it was defined in) will also be maintained. The views do the same but after the execution of their constructors the children do not maintain a reference to their parents.

If I set any or all of the vars declared above to null it isn't going to make a difference to anything (similarly when it finished that "main" scope). They will still be active and pipe data from stdin to stdout and stderr.

If I set them all to null it would be impossible to have them removed or GCed without clearing out the events on stdin or setting stdin to null (assuming it can be freed like this). You basically have a memory leak that way with in effect orphaned objects if the rest of the code needs stdin and has other important events on it prohibiting you from doing the aforementioned.

To get rid of df, v1 and v2 I need to call a destroy method on each of them. In terms of implementation this means that both the Filter and View methods need to keep the reference to the anonymous listener function they create as well as the observable and pass that to removeListener.

On a side note, alternatively you can have an obserable that returns an index to keep track of listeners so that you can add prototyped functions which at least to my understanding should be much better on performance and memory. You still have to keep track of the returned identifier though and pass your object to ensure that the listener is bound to it when called.

A destroy function adds several pains. First is that I would have to call it and free the reference:

df.destroy();
v1.destroy();
v2.destroy();
df = v1 = v2 = null;

This is a minor annoyance as it's a bit more code but that is not the real problem. When I hand these references around to many objects. In this case when exactly do you call destroy? You cannot simply hand these off to other objects. You'll end up with chains of destroys and manual implementation of tracking either through program flow or some other means. You can't fire and forget.

An example of this kind of problem is if I decide that View will also call destroy on df when it is destroyed. If v2 is still around destroying df will break it so destroy cannot simply be relayed to df. Instead when v1 takes df to use it, it would need to then tell df it is used which would raise some counter or similar to df. df's destroy function would decrease than counter and only actually destroy if it is 0. This sort of thing adds a lot of complexity and adds a lot that can go wrong the most obvious of which is destroying something while there is still a reference around somewhere that will be used and circular references (at this point it's no longer a case of managing a counter but a map of referencing objects). When you're thinking of implementing your own reference counters, MM and so on in JS then it's probably deficient.

If WeakSets were iterable, this could be used:

function Observable() {
    this.events = {open: new WeakSet(), close: new WeakSet()};
}
Observable.prototype.on = function(type, f) {
    this.events[type].add(f);
};
Observable.prototype.emit = function(type, ...args) {
    this.events[type].forEach(f => f(...args));
};
Observable.prototype.off = function(type, f) {
    this.events[type].delete(f);
};

In this case the owning class must also keep a token reference to f otherwise it will go poof.

If Observable were used instead of EventListener then memory management would be automatic in regards to the event listeners.

Instead of calling destroy on each object this would be enough to fully remove them:

df = v1 = v2 = null;

If you didn't set df to null it would still exist but v1 and v2 would automatically be unhooked.

There are two problems with this approach however.

Problem one is that it adds a new complexity. Sometimes people do not actually want this behaviour. I could create a very large chain of objects linked to each other by events rather than containment (references in constructor scopes or object properties). Eventually a tree and I would only have to pass around the root and worry about that. Freeing the root would conveniently free the entire thing. Both behaviours depending on coding style, etc are useful and when creating reusable objects it's going to be hard to either know what people want, what they have done, what you have done and a pain to work around what has been done. If I use Observable instead of EventListener then either df will need to reference v1 and v2 or I'll have to pass them all if I want to transfer ownership of the reference to something else out of scope. A weak reference like thing would mitigate the problem a little by transferring control from Observable to an observer but would not solve it entirely (and needs check on every emit or event on itself). This problem can be fixed I suppose if the behaviour only applies to isolated graphs which would complicate the GC severely and would not apply to cases where there are references outside the graph that are in practice noops (only consume CPU cycles, no changes made).

Problem two is that either it is unpredictable in certain cases or forces the JS engine to traverse the GC graph for those objects on demand which can have a horrific performance impact (although if it is clever it can avoid doing it per member by doing it per WeakMap loop instead). The GC may never run if memory usage does not reach a certain threshold and the object with its events wont be removed. If I set v1 to null it may still relay to stdout forever. Even if it does get GCed this will be arbitrary, it may continue to relay to stdout for any amount of time (1 lines, 10 lines, 2.5 lines, etc).

The reason WeakMap gets away with not caring about the GC when non-iterable is that to access an object you have to have a reference to it anyway so either it hasn't been GCed or hasn't been added to the map.

I am not sure what I think about this kind of thing. You're sort of breaking memory management to fix it with the iterable WeakMap approach. Problem two can also exist for destructors as well.

All of this invokes several levels of hell so I would suggest to try to work around it with good program design, good practices, avoiding certain things, etc. It can be frustrating in JS however because of how flexible it is in certain aspects and because it is more naturally asynchronous and event based with heavy inversion of control.

There is one other solution that is fairly elegant but again still has some potentially serious hangups. If you have a class that extends an observable class you can override the event functions. Add your events to other observables only when events are added to yourself. When all events are removed from you then remove your events from children. You can also make a class to extend your observable class to do this for you. Such a class could provide hooks for empty and non-empty so in a since you would be Observing yourself. This approach isn't bad but also has hangups. There is a complexity increase as well as performance decrease. You'll have to keep a reference to object you observe. Critically, it also will not work for leaves but at least the intermediates will self destruct if you destroy the leaf. It's like chaining destroy but hidden behind calls that you already have to chain. A large performance problem is with this however is that you may have to reinitialise internal data from the Observable everytime your class becomes active. If this process takes a very long time then you might be in trouble.

If you could iterate WeakMap then you could perhaps combine things (switch to Weak when no events, Strong when events) but all that is really doing is putting the performance problem on someone else.

There are also immediate annoyances with iterable WeakMap when it comes to behaviour. I mentioned briefly before about functions having scope references and carving. If I instantiate a child that in the constructor that hooks the listener 'console.log(param)' to parent and fails to persist the parent then when I remove all references to the child it could be freed entirely as the anonymous function added to the parent references nothing from within the child. This leaves the question of what to do about parent.weakmap.add(child, (param) => console.log(param)). To my knowledge the key is weak but not the value so weakmap.add(object, object) is persistent. This is something I need to reevaluate though. To me that looks like a memory leak if I dispose all other object references but I suspect in reality it manages that basically by seeing it as a circular reference. Either the anonymous function maintains an implicit reference to objects resulting from parent scopes for consistency wasting a lot of memory or you have behaviour varying based on circumstances which is hard to predict or manage. I think the former is actually impossible. In the latter case if I have a method on a class that simply takes an object and adds console.log it would be freed when I clear the references to the class even if I returned the function and maintained a reference. To be fair this particular scenario is rarely needed legitimately but eventually someone will find an angle and will be asking for a HalfWeakMap which is iterable (free on key and value refs released) but that is unpredictable as well (obj = null magically ending IO, f = null magically ending IO, both doable at incredible distances).

What precisely does 'Run as administrator' do?

A little clearer... A software program that has kernel mode access has total access to all of the computer's data and its hardware.

Since Windows Vista Microsoft has stopped any and all I/O processes from accessing the kernel (ring 0) directly ever again. The closest we get is a folder created as a virtual kernel access partition, but technically no access to kernel itself; the kernel meets halfway.

This is because the software itself dictates which token to use, so if it asks for an administrator access token, instead of just allowing communications with the kernel like on Windows XP you are prompted to allow access to the kernel, each and every time. Changing UAC could reduce prompts, but never the kernel prompts.

Even when you login as an Administrator, you are running processes as a standard user until prompted to elevate the rights you have. I believe logged in as the administrator saves you from entering the credentials. But it also writes to the administrator users folder structure.

Kernel access is similar to root access in Linux. When you elevate your permissions you are isolating yourself from the root of C:\ and whatever lovely environment variables are contained within.

If you remember BSODs this was the OS shutting down when it believed a bad I/O reached the kernel.

How to create a custom exception type in Java?

You need to create a class that extends from Exception. It should look like this:

public class MyOwnException extends Exception {
    public MyOwnException () {

    }

    public MyOwnException (String message) {
        super (message);
    }

    public MyOwnException (Throwable cause) {
        super (cause);
    }

    public MyOwnException (String message, Throwable cause) {
        super (message, cause);
    }
}

Your question does not specify if this new exception should be checked or unchecked.

As you can see here, the two types are different:

  • Checked exceptions are meant to flag a problematic situation that should be handled by the developer who calls your method. It should be possible to recover from such an exception. A good example of this is a FileNotFoundException. Those exceptions are subclasses of Exception.

  • Unchecked exceptions are meant to represent a bug in your code, an unexpected situation that you might not be able to recover from. A NullPointerException is a classical example. Those exceptions are subclasses of RuntimeException

Checked exception must be handled by the calling method, either by catching it and acting accordingly, or by throwing it to the calling method. Unchecked exceptions are not meant to be caught, even though it is possible to do so.

Assign an initial value to radio button as checked

You can use the checked attribute for this:

<input type="radio" checked="checked">

Print execution time of a shell command

Just ps -o etime= -p "<your_process_pid>"

C# HttpClient 4.5 multipart/form-data upload

public async Task<object> PassImageWithText(IFormFile files)
{
    byte[] data;
    string result = "";
    ByteArrayContent bytes;

    MultipartFormDataContent multiForm = new MultipartFormDataContent();

    try
    {
        using (var client = new HttpClient())
        {
            using (var br = new BinaryReader(files.OpenReadStream()))
            {
                data = br.ReadBytes((int)files.OpenReadStream().Length);
            }

            bytes = new ByteArrayContent(data);
            multiForm.Add(bytes, "files", files.FileName);
            multiForm.Add(new StringContent("value1"), "key1");
            multiForm.Add(new StringContent("value2"), "key2");

            var res = await client.PostAsync(_MEDIA_ADD_IMG_URL, multiForm);
        }
    }
    catch (Exception e)
    {
        throw new Exception(e.ToString());
    }

    return result;
}

Ansible date variable

Note that the ansible command doesn't collect facts, but the ansible-playbook command does. When running ansible -m setup, the setup module happens to run the fact collection so you get the facts, but running ansible -m command does not. Therefore the facts aren't available. This is why the other answers include playbook YAML files and indicate the lookup works.

Format Date output in JSF

With EL 2 (Expression Language 2) you can use this type of construct for your question:

    #{formatBean.format(myBean.birthdate)}

Or you can add an alternate getter in your bean resulting in

    #{myBean.birthdateString}

where getBirthdateString returns the proper text representation. Remember to annotate the get method as @Transient if it is an Entity.

How can I define an interface for an array of objects with Typescript?

Do not use

interface EnumServiceGetOrderBy {
    [index: number]: { id: number; label: string; key: any };
}

You will get errors for all the Arrays properties and methods such as splice etc.

The solution is to create an interface that defines an array of another interface (which will define the object)

For example:

interface TopCategoriesProps {
  data: Array<Type>;
}
interface Type {
  category: string;
  percentage: number;
}

Controller 'ngModel', required by directive '...', can't be found

As described here: Angular NgModelController, you should provide the <input with the required controller ngModel

<input submit-required="true" ng-model="user.Name"></input>

How to see top processes sorted by actual memory usage?

ps aux | awk '{print $2, $4, $11}' | sort -k2rn | head -n 10

(Adding -n numeric flag to sort command.)

IntelliJ does not show 'Class' when we right click and select 'New'

The directory or one of the parent directories must be marked as Source Root (In this case, it appears in blue).

If this is not the case, right click your root source directory -> Mark As -> Source Root.

Importing json file in TypeScript

In your TS Definition file, e.g. typings.d.ts`, you can add this line:

declare module "*.json" {
const value: any;
export default value;
}

Then add this in your typescript(.ts) file:-

import * as data from './colors.json';
const word = (<any>data).name;

Read a javascript cookie by name

using jquery-cookie

I find this library helpful. 3.128 kb of pure convenience.

add script

<script src="/path/to/jquery.cookie.js"></script>

set cookie

$.cookie('name', 'value');

read cookie

$.cookie('name');

Change first commit of project with Git?

git rebase -i allows you to conveniently edit any previous commits, except for the root commit. The following commands show you how to do this manually.

# tag the old root, "git rev-list ..." will return the hash of first commit
git tag root `git rev-list HEAD | tail -1`

# switch to a new branch pointing at the first commit
git checkout -b new-root root

# make any edits and then commit them with:
git commit --amend

# check out the previous branch (i.e. master)
git checkout @{-1}

# replace old root with amended version
git rebase --onto new-root root

# you might encounter merge conflicts, fix any conflicts and continue with:
# git rebase --continue

# delete the branch "new-root"
git branch -d new-root

# delete the tag "root"
git tag -d root

Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist

If you have a server which used to happily run MySQL, but now gives this error, then an uninstall and re-install of MySQL is overkill.

In my case, the server died and took a few disk blocks with it. This affected a few files, including /var/lib/mysql/mysql/host.frm and /var/lib/mysql/mysql/proc.frm

Luckily, I could copy these from another server, and this got me past that table error.

Border in shape xml

If you want make a border in a shape xml. You need to use:

For the external border,you need to use:

<stroke/>

For the internal background,you need to use:

<solid/>

If you want to set corners,you need to use:

<corners/>

If you want a padding betwen border and the internal elements,you need to use:

<padding/>

Here is a shape xml example using the above items. It works for me

<shape xmlns:android="http://schemas.android.com/apk/res/android"> 
  <stroke android:width="2dp" android:color="#D0CFCC" /> 
  <solid android:color="#F8F7F5" /> 
  <corners android:radius="10dp" />
  <padding android:left="2dp" android:top="2dp" android:right="2dp" android:bottom="2dp" />
</shape>

How does a hash table work?

Here's another way to look at it.

I assume you understand the concept of an array A. That's something that supports the operation of indexing, where you can get to the Ith element, A[I], in one step, no matter how large A is.

So, for example, if you want to store information about a group of people who all happen to have different ages, a simple way would be to have an array that is large enough, and use each person's age as an index into the array. Thay way, you could have one-step access to any person's information.

But of course there could be more than one person with the same age, so what you put in the array at each entry is a list of all the people who have that age. So you can get to an individual person's information in one step plus a little bit of search in that list (called a "bucket"). It only slows down if there are so many people that the buckets get big. Then you need a larger array, and some other way to get more identifying information about the person, like the first few letters of their surname, instead of using age.

That's the basic idea. Instead of using age, any function of the person that produces a good spread of values can be used. That's the hash function. Like you could take every third bit of the ASCII representation of the person's name, scrambled in some order. All that matters is that you don't want too many people to hash to the same bucket, because the speed depends on the buckets remaining small.

Android Studio: Module won't show up in "Edit Configuration"

In your module build.gradle file make sure you have the correct plugin set. it should be

apply plugin: 'android'

How do I set a column value to NULL in SQL Server Management Studio?

If you are using the table interface you can type in NULL (all caps)

otherwise you can run an update statement where you could:

Update table set ColumnName = NULL where [Filter for record here]

how do I use an enum value on a switch statement in C++

You're on the right track. You may read the user input into an integer and switch on that:

enum Choice
{
  EASY = 1, 
  MEDIUM = 2, 
  HARD = 3
};

int i = -1;

// ...<present the user with a menu>...

cin >> i;

switch(i)
{
  case EASY:
    cout << "Easy\n";
    break;
  case MEDIUM:
    cout << "Medium\n";
    break;
  case HARD:
    cout << "Hard\n";
    break;
  default:
    cout << "Invalid Selection\n";
    break;
}

How to copy from CSV file to PostgreSQL table with headers in CSV file?

I have been using this function for a while with no problems. You just need to provide the number columns there are in the csv file, and it will take the header names from the first row and create the table for you:

create or replace function data.load_csv_file
    (
        target_table  text, -- name of the table that will be created
        csv_file_path text,
        col_count     integer
    )

    returns void

as $$

declare
    iter      integer; -- dummy integer to iterate columns with
    col       text; -- to keep column names in each iteration
    col_first text; -- first column name, e.g., top left corner on a csv file or spreadsheet

begin
    set schema 'data';

    create table temp_table ();

    -- add just enough number of columns
    for iter in 1..col_count
    loop
        execute format ('alter table temp_table add column col_%s text;', iter);
    end loop;

    -- copy the data from csv file
    execute format ('copy temp_table from %L with delimiter '','' quote ''"'' csv ', csv_file_path);

    iter := 1;
    col_first := (select col_1
                  from temp_table
                  limit 1);

    -- update the column names based on the first row which has the column names
    for col in execute format ('select unnest(string_to_array(trim(temp_table::text, ''()''), '','')) from temp_table where col_1 = %L', col_first)
    loop
        execute format ('alter table temp_table rename column col_%s to %s', iter, col);
        iter := iter + 1;
    end loop;

    -- delete the columns row // using quote_ident or %I does not work here!?
    execute format ('delete from temp_table where %s = %L', col_first, col_first);

    -- change the temp table name to the name given as parameter, if not blank
    if length (target_table) > 0 then
        execute format ('alter table temp_table rename to %I', target_table);
    end if;
end;

$$ language plpgsql;

Android Log.v(), Log.d(), Log.i(), Log.w(), Log.e() - When to use each one?

I think the point of those different types of logging is if you want your app to basically self filter its own logs. So Verbose could be to log absolutely everything of importance in your app, then the debug level would log a subset of the verbose logs, and then Info level will log a subset of the debug logs. When you get down to the Error logs, then you just want to log any sort of errors that may have occured. There is also a debug level called Fatal for when something really hits the fan in your app.

In general, you're right, it's basically arbitrary, and it's up to you to define what is considered a debug log versus informational, versus and error, etc. etc.

How to deny access to a file in .htaccess

I don't believe the currently accepted answer is correct. For example, I have the following .htaccess file in the root of a virtual server (apache 2.4):

<Files "reminder.php">
require all denied
require host localhost
require ip 127.0.0.1
require ip xxx.yyy.zzz.aaa
</Files>

This prevents external access to reminder.php which is in a subdirectory. I have a similar .htaccess file on my Apache 2.2 server with the same effect:

<Files "reminder.php">
        Order Deny,Allow
        Deny from all
        Allow from localhost
        Allow from 127.0.0.1
     Allow from xxx.yyy.zzz.aaa
</Files>

I don't know for sure but I suspect it's the attempt to define the subdirectory specifically in the .htaccess file, viz <Files ./inscription/log.txt> which is causing it to fail. It would be simpler to put the .htaccess file in the same directory as log.txt i.e. in the inscription directory and it will work there.

MySQL and GROUP_CONCAT() maximum length

SET SESSION group_concat_max_len = 1000000;

is a temporary, session-scope, setting. It only applies to the current session You should use it like this.

SET SESSION group_concat_max_len = 1000000;
select group_concat(column) from table group by column

You can do this even in sharing hosting, but when you use an other session, you need to repeat the SET SESSION command.

Logo image and H1 heading on the same line

As example (DEMO):

HTML:

<div class="header">
  <img src="img/logo.png" alt="logo" />
  <h1>My website name</h1>
</div>

CSS:

.header img {
  float: left;
  width: 100px;
  height: 100px;
  background: #555;
}

.header h1 {
  position: relative;
  top: 18px;
  left: 10px;
}

DEMO

RadioGroup: How to check programmatically

Watch out! checking the radiobutton with setChecked() is not changing the state inside the RadioGroup. For example this method from the radioGroup will return a wrong result: getCheckedRadioButtonId().

Check the radioGroup always with

mOption.check(R.id.option1);

you've been warned ;)

Where does PHP's error log reside in XAMPP?

As said above you can find PHP error log in windows. In c:\xampp\apache\logs\error.log. You can easily display the last logs by tail -f .\error.log

How to open my files in data_folder with pandas using relative path?

Pandas will start looking from where your current python file is located. Therefore you can move from your current directory to where your data is located with '..' For example:

pd.read_csv('../../../data_folder/data.csv')

Will go 3 levels up and then into a data_folder (assuming it's there) Or

pd.read_csv('data_folder/data.csv')

assuming your data_folder is in the same directory as your .py file.

Adding a y-axis label to secondary y-axis in matplotlib

The best way is to interact with the axes object directly

import numpy as np
import matplotlib.pyplot as plt
x = np.arange(0, 10, 0.1)
y1 = 0.05 * x**2
y2 = -1 *y1

fig, ax1 = plt.subplots()

ax2 = ax1.twinx()
ax1.plot(x, y1, 'g-')
ax2.plot(x, y2, 'b-')

ax1.set_xlabel('X data')
ax1.set_ylabel('Y1 data', color='g')
ax2.set_ylabel('Y2 data', color='b')

plt.show()

example graph

Debugging JavaScript in IE7

you might want to try microsoft script debugger it's pretty old but it's quite useful in the sense if you stumble on any javascript error, the debugger will popup to show you which line is messing up. it could get irrating sometimes when you do normal surfing, but you can turn if off.

here's a good startup on how to use this tool too. HOW-TO: Debug JavaScript in Internet Explorer

MySQLi prepared statements error reporting

Not sure if this answers your question or not. Sorry if not

To get the error reported from the mysql database about your query you need to use your connection object as the focus.

so:

echo $mysqliDatabaseConnection->error

would echo the error being sent from mysql about your query.

Hope that helps

How to specify function types for void (not Void) methods in Java8?

I feel you should be using the Consumer interface instead of Function<T, R>.

A Consumer is basically a functional interface designed to accept a value and return nothing (i.e void)

In your case, you can create a consumer elsewhere in your code like this:

Consumer<Integer> myFunction = x -> {
    System.out.println("processing value: " + x);    
    .... do some more things with "x" which returns nothing...
}

Then you can replace your myForEach code with below snippet:

public static void myForEach(List<Integer> list, Consumer<Integer> myFunction) 
{
  list.forEach(x->myFunction.accept(x));
}

You treat myFunction as a first-class object.

How to disassemble a memory range with GDB?

Yeah, disassemble is not the best command to use here. The command you want is "x/i" (examine as instructions):

(gdb) x/i 0xdeadbeef

Daemon not running. Starting it now on port 5037

Reference link: http://www.programering.com/a/MTNyUDMwATA.html

Steps I followed 1) Execute the command adb nodaemon server in command prompt Output at command prompt will be: The following error occurred cannot bind 'tcp:5037' The original ADB server port binding failed

2) Enter the following command query which using port 5037 netstat -ano | findstr "5037" The following information will be prompted on command prompt: TCP 127.0.0.1:5037 0.0.0.0:0 LISTENING 9288

3) View the task manager, close all adb.exe

4) Restart eclipse or other IDE

The above steps worked for me.

Android simple alert dialog

No my friend its very simple, try using this:

AlertDialog alertDialog = new AlertDialog.Builder(AlertDialogActivity.this).create();
alertDialog.setTitle("Alert Dialog");
alertDialog.setMessage("Welcome to dear user.");
alertDialog.setIcon(R.drawable.welcome);

alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int which) {
        Toast.makeText(getApplicationContext(), "You clicked on OK", Toast.LENGTH_SHORT).show();
    }
});

alertDialog.show();

This tutorial shows how you can create custom dialog using xml and then show them as an alert dialog.

How to change the new TabLayout indicator color and height

To change indicator color and height programmatically you can use reflection. for example for indicator color use code below:

        try {
            Field field = TabLayout.class.getDeclaredField("mTabStrip");
            field.setAccessible(true);
            Object ob = field.get(tabLayout);
            Class<?> c = Class.forName("android.support.design.widget.TabLayout$SlidingTabStrip");
            Method method = c.getDeclaredMethod("setSelectedIndicatorColor", int.class);
            method.setAccessible(true);
            method.invoke(ob, Color.RED);//now its ok
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

and to change indicator height use "setSelectedIndicatorHeight" instead of "setSelectedIndicatorColor" then invoke it by your desired height

How to fit in an image inside span tag?

Try using a div tag and block for span!

<div>
  <span style="padding-right:3px; padding-top: 3px; display:block;">
    <img class="manImg" src="images/ico_mandatory.gif"></img>
  </span>
</div>

changing color of h2

If you absolutely must use HTML to give your text color, you have to use the (deprecated) <font>-tag:

<h2><font color="#006699">Process Report</font></h2>

But otherwise, I strongly recommend you to do as rekire said: use CSS.

How do I stop/start a scheduled task on a remote computer programmatically?

Try this:

schtasks /change /ENABLE /tn "Auto Restart" /s mycomutername /u mycomputername\username/p mypassowrd

What are my options for storing data when using React Native? (iOS and Android)

you can use sync storage that is easier to use than async storage. this library is great that uses async storage to save data asynchronously and uses memory to load and save data instantly synchronously, so we save data async to memory and use in app sync, so this is great.

import SyncStorage from 'sync-storage';

SyncStorage.set('foo', 'bar');
const result = SyncStorage.get('foo');
console.log(result); // 'bar'

VERR_VMX_MSR_VMXON_DISABLED when starting an image from Oracle virtual box

I had the same problem. I enabled vtx in bios and it didn't worked. After a doublecheck in the bios I recogniced that the bios said that you have to poweroff (and realy power off) the computer. After that it worked. Heavy Pitfall :)

Javascript: output current datetime in YYYY/mm/dd hh:m:sec format

Posting another script solution DateX (author) for anyone interested

DateX does NOT wrap the original Date object, but instead offers an identical interface with additional methods to format, localise, parse, diff and validate dates easily. So one can just do new DateX(..) instead of new Date(..) or use the lib as date utilities or even as wrapper or replacement around Date class.

The date format used is identical to php date format.

c-like format is also supported (although not fully)

for the example posted (YYYY/mm/dd hh:m:sec) the format to use would be Y/m/d H:i:s eg

var formatted_date = new DateX().format('Y/m/d H:i:s');

or

var formatted_now_date_gmt = new DateX(DateX.UTC()).format('Y/m/d H:i:s');

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/UTC

Select2() is not a function

Had the same issue. Sorted it by defer loading select2

<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.8/js/select2.min.js" defer></script>

CSS submit button weird rendering on iPad/iPhone

Add this code into the css file:

input {
-webkit-appearance: none;
-moz-appearance: none;
appearance: none;
}

This will help.

How do I use a char as the case in a switch-case?

public class SwitCase {
    public static void main (String[] args){
        String hello = JOptionPane.showInputDialog("Input a letter: ");
        char hi = hello.charAt(0); //get the first char.
        switch(hi){
            case 'a': System.out.println("a");
        }
    }   
}

org.apache.poi.POIXMLException: org.apache.poi.openxml4j.exceptions.InvalidFormatException:

You are trying to access an XLS file. However, you are using XSSFWorkbook and XSSFSheet class objects. These classes are mainly used for XLSX files.

For XLS file: HSSFWorkbook & HSSFSheet
For XLSX file: XSSFSheet & XSSFSheet

So in place of XSSFWorkbook use HSSFWorkbook and in place of XSSFSheet use HSSFSheet.

So your code should look like this after the changes are made:

HSSFWorkbook workbook = new HSSFWorkbook(file);

HSSFSheet sheet = workbook.getSheetAt(0);

How to install JRE 1.7 on Mac OS X and use it with Eclipse?

You need to tell Eclipse which JDK/JRE's you have installed and where they are located.

This is somewhat burried in the Eclipse preferences: In the Window-Menu select "Preferences". In the Preferences Tree, open the Node "Java" and select "Installed JRE's". Then click on the "Add"-Button in the Panel and select "Standard VM", "Next" and for "JRE Home" click on the "Directory"-Button and select the top level folder of the JDK you want to add.

Its easier than the description may make it look.

IntelliJ IDEA "cannot resolve symbol" and "cannot resolve method"

For me, IntelliJ could autocomplete packages, but never seemed to admit there were actual classes at any level of the hierarchy. Neither re-choosing the SDK nor re-creating the project seemed to fix it.

What did fix it was to delete the per-user IDEA directory ( in my case ~/.IntelliJIdea2017.1/) which meant losing all my other customizations... But at least it made the issue go away.

Error :Request header field Content-Type is not allowed by Access-Control-Allow-Headers

I know it's an old thread I worked with above answer and had to add:

header('Access-Control-Allow-Methods: GET, POST, PUT');

So my header looks like:

header('Access-Control-Allow-Origin: *');
header("Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept");
header('Access-Control-Allow-Methods: GET, POST, PUT');

And the problem was fixed.

Create a batch file to copy and rename file

type C:\temp\test.bat>C:\temp\test.log

Join between tables in two different databases?

SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;

Just make sure that in the SELECT line you specify which table columns you are using, either by full reference, or by alias. Any of the following will work:

SELECT *
SELECT t1.*,t2.column2
SELECT A.table1.column1, t2.*
etc.

Detect if HTML5 Video element is playing

I just did it very simply using onpause and onplay properties of the html video tag. Create some javascript function to toggle a global variable so that the page knows the status of the video for other functions.

Javascript below:

   // onPause function
   function videoPause() {
      videoPlaying = 0;
   }

   // onPause function
   function videoPlay() {
      videoPlaying = 1;
   }

Html video tag:

<video id="mainVideo" width="660" controls onplay="videoPlay();" onpause="videoPause();" >
                             <source src="video/myvideo.mp4" type="video/mp4">

                            </video>

than you can use onclick javascript to do something depending on the status variable in this case videoPlaying.

hope this helps...

Recommended way to embed PDF in HTML?

  1. Construct a blob of the input PDF bytes
  2. Use an iframe and PDF.js patched with this cross browser workaround

The URI for the iframe should look something like this:

/viewer.html?file=blob:19B579EA-5217-41C6-96E4-5D8DF5A5C70B

Now FF, Chrome, IE 11, and Edge all display the PDF in a viewer in the iframe passed via standard blob URI in the URL.

How to add new activity to existing project in Android Studio?

In Android Studio 2, just right click on app and select New > Activity > ... to create desired activity type.

enter image description here

Apple Mach-O Linker Error when compiling for device

This error can also be occurred if you have imported two different versions of same library ,in this case just remove the older version and keep only one version and Magic will work for you.

The database cannot be opened because it is version 782. This server supports version 706 and earlier. A downgrade path is not supported

Try changing Tools > Options > Database Tools > Data Connections > SQL Server Instance Name.

The default for VS2013 is (LocalDB)\v11.0.

Changing to (LocalDB)\MSSQLLocalDB, for example, seems to work - no more version 782 error.

Android custom Row Item for ListView

create resource layout file list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:orientation="vertical"
          android:layout_width="match_parent"
          android:layout_height="wrap_content">
<TextView
        android:id="@+id/header_text"
        android:layout_height="0dp"
        android:layout_width="fill_parent"
        android:layout_weight="1"
        android:text="Header"
        />
<TextView
        android:id="@+id/item_text"
        android:layout_height="0dp"
        android:layout_width="fill_parent"
        android:layout_weight="1"
        android:text="dynamic text"
        />
</LinearLayout>

and initialise adaptor like this

adapter = new ArrayAdapter<String>(this, R.layout.list_item,R.id.item_text,data_array);

https connection using CURL from command line

use --cacert to specify a .crt file. ca-root-nss.crt for example.

How to convert 'binary string' to normal string in Python3?

Please, see oficial encode() and decode() documentation from codecs library. utf-8 is the default encoding for the functions, but there are severals standard encodings in Python 3, like latin_1 or utf_32.

Responsive image map

Check out the image-map plugin on Github. It works both with vanilla JavaScript and as a jQuery plugin.

$('img[usemap]').imageMap();     // jQuery

ImageMap('img[usemap]')          // JavaScript

Check out the demo.

How do you enable auto-complete functionality in Visual Studio C++ express edition?

It's enabled by default. Probably you just tried on an expression that failed to autocomplete.

In case you deactivated it somehow... you can enable it in the Visual Studio settings. Just browse to the Editor settings, then to the subgroup C/C++ and activate it again... should read something like "List members automatically" or "Auto list members" (sorry, I have the german Visual Studio).

Upon typing something like std::cout. a dropwdownlist with possible completitions should pop up.

Failed to add a service. Service metadata may not be accessible. Make sure your service is running and exposing metadata.`

You need to add a metadata exchange (mex) endpoint to your service:

<services>
   <service name="MyService.MyService" behaviorConfiguration="metadataBehavior">
      <endpoint 
          address="http://localhost/MyService.svc" 
          binding="customBinding" bindingConfiguration="jsonpBinding" 
          behaviorConfiguration="MyService.MyService"
          contract="MyService.IMyService"/>
      <endpoint 
          address="mex" 
          binding="mexHttpBinding" 
          contract="IMetadataExchange"/>
   </service>
</services>

Now, you should be able to get metadata for your service

Update: ok, so you're just launching this from Visual Studio - in that case, it will be hosted in Cassini, the built-in web server. That beast however only supports HTTP - you're not using that protocol in your binding...

Also, since you're hosting this in Cassini, the address of your service will be dictated by Cassini - you don't get to define anything.

So my suggestion would be:

  • try to use http binding (just now for testing)
  • get this to work
  • once you know it works, change it to your custom binding and host it in IIS

So I would change the config to:

<behaviors>
   <serviceBehaviors>
      <behavior name="metadataBehavior">
         <serviceMetadata httpGetEnabled="true" />
      </behavior>
   </serviceBehaviors>
</behaviors>
<services>
   <service name="MyService.MyService" behaviorConfiguration="metadataBehavior">
      <endpoint 
          address=""   <!-- don't put anything here - Cassini will determine address -->
          binding="basicHttpBinding" 
          contract="MyService.IMyService"/>
      <endpoint 
          address="mex" 
          binding="mexHttpBinding" 
          contract="IMetadataExchange"/>
   </service>
</services>

Once you have that, try to do a View in Browser on your SVC file in your Visual Studio solution - if that doesn't work, you still have a major problem of some sort.

If it works - now you can press F5 in VS and your service should come up, and using the WCF Test Client app, you should be able to get your service metadata from a) the address that Cassini started your service on, or b) the mex address (Cassini's address + /mex)

Hbase quickly count number of rows

You can use coprocessor what is available since HBase 0.92. See Coprocessor and AggregateProtocol and example

Create instance of generic type whose constructor requires a parameter?

Recently I came across a very similar problem. Just wanted to share our solution with you all. I wanted to I created an instance of a Car<CarA> from a json object using which had an enum:

Dictionary<MyEnum, Type> mapper = new Dictionary<MyEnum, Type>();

mapper.Add(1, typeof(CarA));
mapper.Add(2, typeof(BarB)); 

public class Car<T> where T : class
{       
    public T Detail { get; set; }
    public Car(T data)
    {
       Detail = data;
    }
}
public class CarA
{  
    public int PropA { get; set; }
    public CarA(){}
}
public class CarB
{
    public int PropB { get; set; }
    public CarB(){}
}

var jsonObj = {"Type":"1","PropA":"10"}
MyEnum t = GetTypeOfCar(jsonObj);
Type objectT = mapper[t]
Type genericType = typeof(Car<>);
Type carTypeWithGenerics = genericType.MakeGenericType(objectT);
Activator.CreateInstance(carTypeWithGenerics , new Object[] { JsonConvert.DeserializeObject(jsonObj, objectT) });

How do I clear a C++ array?

If only to 0 then you can use memset:

int* a = new int[6];

memset(a, 0, 6*sizeof(int));

How to show x and y axes in a MATLAB graph?

Easiest solution:

plot([0,0],[0.0], xData, yData);

This creates an invisible line between the points [0,0] to [0,0] and since Matlab wants to include these points it will shows the axis.

How to use http.client in Node.js if there is basic authorization

var username = "Ali";
var password = "123";
var auth = "Basic " + new Buffer(username + ":" + password).toString("base64");
var request = require('request');
var url = "http://localhost:5647/contact/session/";

request.get( {
    url : url,
    headers : {
        "Authorization" : auth
    }
  }, function(error, response, body) {
      console.log('body : ', body);
  } );

What does \0 stand for?

It means '\0' is a NULL character in C, don't know about Objective-C but its probably the same.

IE6/IE7 css border on select element

It solves to me, for my purposes:

.select-container {
  position:relative;
  width:200px;
  height:18px;
  overflow:hidden;
  border:1px solid white !important
}
.select-container select {
  position:relative;
  left:-2px;
  top:-2px
}

To put more style will be necessary to use nested divs .

Difference between MongoDB and Mongoose

If you are planning to use these components along with your proprietary code then please refer below information.

Mongodb:

  1. It's a database.
  2. This component is governed by the Affero General Public License (AGPL) license.
  3. If you link this component along with your proprietary code then you have to release your entire source code in the public domain, because of it's viral effect like (GPL, LGPL etc)
  4. If you are hosting your application over the cloud, the (2) will apply and also you have to release your installation information to the end users.

Mongoose:

  1. It's an object modeling tool.
  2. This component is governed by the MIT license.
  3. Allowed to use this component along with the proprietary code, without any restrictions.
  4. Shipping your application using any media or host is allowed.

How to sort multidimensional array by column?

The optional key parameter to sort/sorted is a function. The function is called for each item and the return values determine the ordering of the sort

>>> lst = [['John', 2], ['Jim', 9], ['Jason', 1]]
>>> def my_key_func(item):
...     print("The key for {} is {}".format(item, item[1]))
...     return item[1]
... 
>>> sorted(lst, key=my_key_func)
The key for ['John', 2] is 2
The key for ['Jim', 9] is 9
The key for ['Jason', 1] is 1
[['Jason', 1], ['John', 2], ['Jim', 9]]

taking the print out of the function leaves

>>> def my_key_func(item):
...     return item[1]

This function is simple enough to write "inline" as a lambda function

>>> sorted(lst, key=lambda item: item[1])
[['Jason', 1], ['John', 2], ['Jim', 9]]

CSS: how to get scrollbars for div inside container of fixed height

FWIW, here is my approach = a simple one that works for me:

<div id="outerDivWrapper">
   <div id="outerDiv">
      <div id="scrollableContent">
blah blah blah
      </div>
   </div>
</div>

html, body {
   height: 100%;
   margin: 0em;
}

#outerDivWrapper, #outerDiv {
   height: 100%;
   margin: 0em;
}

#scrollableContent {
   height: 100%;
   margin: 0em;
   overflow-y: auto;
}

Error: Node Sass does not yet support your current environment: Windows 64-bit with false

I got this error when I updated node using NVM. to remove this run; npm rebuild node-sass

Export table data from one SQL Server to another

Just for the kicks.

Since I wasnt able to create linked server and since just connecting to production server was not enough to use INSERT INTO i did the following:

  • created a backup of production server database
  • restored the database on my test server
  • executed the insert into statements

Its a backdoor solution, but since i had problems it worked for me.

Since i have created empty tables using SCRIPT TABLE AS / CREATE in order to transfer all the keys and indexes I couldnt use SELECT INTO. SELECT INTO only works if the tables do not exist on the destination location but it does not copy keys and indexes, so you have to do that manualy. The downside of using INSERT INTO statement is that you have to manualy provide with all the column names, plus it might give you some problems if some foreign key constraints fail.

Thanks to all anwsers, there are some great solutions but i have decided to accept marc_s anwser.

Convert string to date in bash

We can use date -d option

1) Change format to "%Y-%m-%d" format i.e 20121212 to 2012-12-12

date -d '20121212' +'%Y-%m-%d'

2)Get next or last day from a given date=20121212. Like get a date 7 days in past with specific format

date -d '20121212 -7 days' +'%Y-%m-%d'

3) If we are getting date in some variable say dat

dat2=$(date -d "$dat -1 days" +'%Y%m%d')

How to import csv file in PHP?

$row = 1;
    $arrResult  = array();
    if (($handle = fopen("ifsc_code.csv", "r")) !== FALSE) {
        while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
            $num = count($data);
            DB::table('banks')->insert(
                array('bank_name' => $data[1], 'ifsc' => $data[2], 'micr' => $data[3], 'branch_name' => $data[4],'address' => $data[5], 'contact' => $data[6], 'city' => $data[7],'district' => $data[8],'state' => $data[9])
            );
        }
        fclose($handle);
    }

jQuery trigger file input

This is a very old question, but unfortunately this issue is still relevant and requires a solution.

The (suprisingly simple) solution I've come up with is to "hide" the actual file input field and wrap it with a LABEL tag (can be based on Bootstrap and HTML5, for enhancement).

See here:Example code here

This way, the real file input field is invisible and all you see is the customized "button" which is actually a modified LABEL element. When you click on this LABEL element, the window for selecting a file comes up and the file you choose will go into the real file input field.

On top of that, you can manipulate the look and behaviour as you wish (for example: get the name of the selected file from the file input file, after selected, and show it somewhere. The LABEL element doesn't do that automatically, of course. I usually just put it inside the LABEL, as its text content).

Beware though! The manipulation of the look and behaviour of this is limited to whatever you can imagine and think of.    ;-)  ;-)

Resource blocked due to MIME type mismatch (X-Content-Type-Options: nosniff)

It might be a wrong path. Ensure in your main app file you have:

app.use(express.static(path.join(__dirname,"public")));

Example link to your css as:

<link href="/css/clean-blog.min.css" rel="stylesheet">

similar for link to js files:

<script src="/js/clean-blog.min.js"></script>

Adding two numbers concatenates them instead of calculating the sum

The following may be useful in general terms.

  • First, HTML form fields are limited to text. That applies especially to text boxes, even if you have taken pains to ensure that the value looks like a number.

  • Second, JavaScript, for better or worse, has overloaded the + operator with two meanings: it adds numbers, and it concatenates strings. It has a preference for concatenation, so even an expression like 3+'4' will be treated as concatenation.

  • Third, JavaScript will attempt to change types dynamically if it can, and if it needs to. For example '2'*'3' will change both types to numbers, since you can’t multiply strings. If one of them is incompatible, you will get NaN, Not a Number.

Your problem occurs because the data coming from the form is regarded as a string, and the + will therefore concatenate rather than add.

When reading supposedly numeric data from a form, you should always push it through parseInt() or parseFloat(), depending on whether you want an integer or a decimal.

Note that neither function truly converts a string to a number. Instead, it will parse the string from left to right until it gets to an invalid numeric character or to the end and convert what has been accepted. In the case of parseFloat, that includes one decimal point, but not two.

Anything after the valid number is simply ignored. They fail if the string doesn’t even start off as a number. Then you will get NaN.

A good general purpose technique for numbers from forms is something like this:

var data=parseInt(form.elements['data'].value); //  or parseFloat

If you’re prepared to coalesce an invalid string to 0, you can use:

var data=parseInt(form.elements['data'].value) || 0;

How to rotate x-axis tick labels in Pandas barplot

Pass param rot=0 to rotate the xticks:

import matplotlib
matplotlib.style.use('ggplot')
import matplotlib.pyplot as plt
import pandas as pd

df = pd.DataFrame({ 'celltype':["foo","bar","qux","woz"], 's1':[5,9,1,7], 's2':[12,90,13,87]})
df = df[["celltype","s1","s2"]]
df.set_index(["celltype"],inplace=True)
df.plot(kind='bar',alpha=0.75, rot=0)
plt.xlabel("")
plt.show()

yields plot:

enter image description here

C library function to perform sort

qsort() is the function you're looking for. You call it with a pointer to your array of data, the number of elements in that array, the size of each element and a comparison function.

It does its magic and your array is sorted in-place. An example follows:

#include <stdio.h>
#include <stdlib.h>
int comp (const void * elem1, const void * elem2) 
{
    int f = *((int*)elem1);
    int s = *((int*)elem2);
    if (f > s) return  1;
    if (f < s) return -1;
    return 0;
}
int main(int argc, char* argv[]) 
{
    int x[] = {4,5,2,3,1,0,9,8,6,7};

    qsort (x, sizeof(x)/sizeof(*x), sizeof(*x), comp);

    for (int i = 0 ; i < 10 ; i++)
        printf ("%d ", x[i]);

    return 0;
}

How to enable file sharing for my app?

Maybe it's obvious for you guys but I scratched my head for a while because the folder didn't show up in the files app. I actually needed to store something in the folder. you could achieve this by

  • saving some files into your document directory of the app
  • move something from iCloud Drive to your app (in the move dialog the folder will show up). As soon as there are no files in your folder anymore, it's gonna disappear from the "on my iPad tab".

Does IE9 support console.log, and is it a real function?

console.log is only defined when the console is open. If you want to check for it in your code make sure you check for for it within the window property

if (window.console)
    console.log(msg)

this throws an exception in IE9 and will not work correctly. Do not do this

if (console) 
    console.log(msg)

Merge unequal dataframes and replace missing rows with 0

Assuming df1 has all the values of x of interest, you could use a dplyr::left_join() to merge and then either a base::replace() or tidyr::replace_na() to replace the NAs as 0s:

library(tidyverse)

# dplyr only:
df_new <- 
  left_join(df1, df2, by = 'x') %>% 
  mutate(y = replace(y, is.na(y), 0))

# dplyr and tidyr:
df_new <- 
  left_join(df1, df2, by = 'x') %>% 
  mutate(y = replace_na(y, 0))

# In the sample data column `x` is a factor, which will give a warning with the join. This can be prevented by converting to a character before the join:
df_new <- 
  left_join(df1 %>% mutate(x = as.character(x)), 
            df2 %>% mutate(x = as.character(x)), 
            by = 'x') %>% 
    mutate(y = replace(y, is.na(y), 0))

What does the 'static' keyword do in a class?

//Here is an example 

public class StaticClass 
{
    static int version;
    public void printVersion() {
         System.out.println(version);
    }
}

public class MainClass 
{
    public static void main(String args[]) {  
        StaticClass staticVar1 = new StaticClass();
        staticVar1.version = 10;
        staticVar1.printVersion() // Output 10

        StaticClass staticVar2 = new StaticClass();
        staticVar2.printVersion() // Output 10
        staticVar2.version = 20;
        staticVar2.printVersion() // Output 20
        staticVar1.printVersion() // Output 20
    }
}

Is there a method for String conversion to Title Case?

Use this method to convert a string to title case :

static String toTitleCase(String word) {
    return Stream.of(word.split(" "))
            .map(w -> w.toUpperCase().charAt(0)+ w.toLowerCase().substring(1))
            .reduce((s, s2) -> s + " " + s2).orElse("");
}

Rails 4: assets not loading in production

change your Production.rb file line

config.assets.compile = false

into

config.assets.compile = true

and also add

config.assets.precompile =  ['*.js', '*.css', '*.css.erb']

What is the difference between getText() and getAttribute() in Selenium WebDriver?

getAttribute() -> It fetches the text that contains one of any attribute in the HTML tag. Suppose there is an HTML tag like

<input name="Name Locator" value="selenium">Hello</input>

Now getAttribute() fetches the data of the attribute of 'value', which is "Selenium".

Returns:

The attribute's current value or null if the value is not set.

driver.findElement(By.name("Name Locator")).getAttribute("value")  //

The field value is retrieved by the getAttribute("value") Selenium WebDriver predefined method and assigned to the String object.

getText() -> delivers the innerText of a WebElement. Get the visible (i.e. not hidden by CSS) innerText of this element, including sub-elements, without any leading or trailing whitespace.

Returns:

The innerText of this element.

driver.findElement(By.name("Name Locator")).getText();

'Hello' will appear

How to make a radio button unchecked by clicking it?

Let's suppose you have a button where on clicking it, you can make all your radio button selection to false. You can write the below code inside the onclick handler.
Below code take radio buttons based on class name and for each element it will mark it to false.

var elements=document.getElementsByClassName('Button');

Array.prototype.forEach.call(elements, function(element) {
  element.checked = false;
});

One time page refresh after first page load

use this

<body onload =  "if (location.search.length < 1){window.location.reload()}">

Parse JSON in JavaScript?

If you use Dojo Toolkit:

require(["dojo/json"], function(JSON){
    JSON.parse('{"hello":"world"}', true);
});

Generator expressions vs. list comprehensions

Python 3.7:

List comprehensions are faster.

enter image description here

Generators are more memory efficient. enter image description here

As all others have said, if you're looking to scale infinite data, you'll need a generator eventually. For relatively static small and medium-sized jobs where speed is necessary, a list comprehension is best.

Convert a string to a datetime

Try converting date like this:

    Dim expenddt as Date = Date.ParseExact(edate, "dd/mm/yyyy", 
System.Globalization.DateTimeFormatInfo.InvariantInfo);

Hope this helps.

MySql Error: 1364 Field 'display_name' doesn't have default value

Also, I had this issue using Laravel, but fixed by changing my database schema to allow "null" inputs on a table where I plan to collect the information from separate forms:

public function up()
{

    Schema::create('trip_table', function (Blueprint $table) {
        $table->increments('trip_id')->unsigned();
        $table->time('est_start');
        $table->time('est_end');
        $table->time('act_start')->nullable();
        $table->time('act_end')->nullable();
        $table->date('Trip_Date');
        $table->integer('Starting_Miles')->nullable();
        $table->integer('Ending_Miles')->nullable();
        $table->string('Bus_id')->nullable();
        $table->string('Event');
        $table->string('Desc')->nullable();
        $table->string('Destination');
        $table->string('Departure_location');
        $table->text('Drivers_Comment')->nullable();
        $table->string('Requester')->nullable();
        $table->integer('driver_id')->nullable();
        $table->timestamps();
    });

}

The ->nullable(); Added to the end. This is using Laravel. Hope this helps someone, thanks!

Creating an abstract class in Objective-C

This thread is kind of old, and most of what I want to share is already here.

However, my favorite method is not mentioned, and AFAIK there’s no native support in the current Clang, so here I go…

First, and foremost (as others have pointed out already) abstract classes are something very uncommon in Objective-C — we usually use composition (sometimes through delegation) instead. This is probably the reason why such a feature doesn’t already exist in the language/compiler — apart from @dynamic properties, which IIRC have been added in ObjC 2.0 accompanying the introduction of CoreData.

But given that (after careful assessment of your situation!) you have come to the conclusion that delegation (or composition in general) isn’t well suited to solving your problem, here’s how I do it:

  1. Implement every abstract method in the base class.
  2. Make that implementation [self doesNotRecognizeSelector:_cmd];
  3. …followed by __builtin_unreachable(); to silence the warning you’ll get for non-void methods, telling you “control reached end of non-void function without a return”.
  4. Either combine steps 2. and 3. in a macro, or annotate -[NSObject doesNotRecognizeSelector:] using __attribute__((__noreturn__)) in a category without implementation so as not to replace the original implementation of that method, and include the header for that category in your project’s PCH.

I personally prefer the macro version as that allows me to reduce the boilerplate as much as possible.

Here it is:

// Definition:
#define D12_ABSTRACT_METHOD {\
 [self doesNotRecognizeSelector:_cmd]; \
 __builtin_unreachable(); \
}

// Usage (assuming we were Apple, implementing the abstract base class NSString):
@implementation NSString

#pragma mark - Abstract Primitives
- (unichar)characterAtIndex:(NSUInteger)index D12_ABSTRACT_METHOD
- (NSUInteger)length D12_ABSTRACT_METHOD
- (void)getCharacters:(unichar *)buffer range:(NSRange)aRange D12_ABSTRACT_METHOD

#pragma mark - Concrete Methods
- (NSString *)substringWithRange:(NSRange)aRange
{
    if (aRange.location + aRange.length >= [self length])
        [NSException raise:NSInvalidArgumentException format:@"Range %@ exceeds the length of %@ (%lu)", NSStringFromRange(aRange), [super description], (unsigned long)[self length]];

    unichar *buffer = (unichar *)malloc(aRange.length * sizeof(unichar));
    [self getCharacters:buffer range:aRange];

    return [[[NSString alloc] initWithCharactersNoCopy:buffer length:aRange.length freeWhenDone:YES] autorelease];
}
// and so forth…

@end

As you can see, the macro provides the full implementation of the abstract methods, reducing the necessary amount of boilerplate to an absolute minimum.

An even better option would be to lobby the Clang team to providing a compiler attribute for this case, via feature requests. (Better, because this would also enable compile-time diagnostics for those scenarios where you subclass e.g. NSIncrementalStore.)

Why I Choose This Method

  1. It get’s the job done efficiently, and somewhat conveniently.
  2. It’s fairly easy to understand. (Okay, that __builtin_unreachable() may surprise people, but it’s easy enough to understand, too.)
  3. It cannot be stripped in release builds without generating other compiler warnings, or errors — unlike an approach that’s based on one of the assertion macros.

That last point needs some explanation, I guess:

Some (most?) people strip assertions in release builds. (I disagree with that habit, but that’s another story…) Failing to implement a required method — however — is bad, terrible, wrong, and basically the end of the universe for your program. Your program cannot work correctly in this regard because it is undefined, and undefined behavior is the worst thing ever. Hence, being able to strip those diagnostics without generating new diagnostics would be completely unacceptable.

It’s bad enough that you cannot obtain proper compile-time diagnostics for such programmer errors, and have to resort to at-run-time discovery for these, but if you can plaster over it in release builds, why try having an abstract class in the first place?

git: 'credential-cache' is not a git command

There is now a much easier way to setup Git password caching by double clicking a small exe on Windows. The program is still based on git-credential-winstore mentioned by the top voted answer, although the project has been moved from GitHub to http://gitcredentialstore.codeplex.com/

You can download the exe (and a binary for Mac) from this blog post: https://github.com/blog/1104-credential-caching-for-wrist-friendly-git-usage

Where is Developer Command Prompt for VS2013?

From VS2013 Menu Select "Tools", then Select "External Tools". Enter as below:

  • Title: "VS2013 Native Tools-Command Prompt" would be good
  • Command: C:\Windows\System32\cmd.exe
  • Arguments: /k "C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\Tools\VsDevCmd.bat"
  • Initial Directory: Select as suits your needs.

Click OK. Now you have command prompt access under the Tools Menu.

How to get current route in Symfony 2?

if you want to get route name in your controller than you have to inject the request (instead of getting from container due to Symfony UPGRADE and than call get('_route').

public function indexAction(Request $request)
{
    $routeName = $request->get('_route');
}

if you want to get route name in twig than you have to get it like

{{ app.request.attributes.get('_route') }}

Display TIFF image in all web browser

Tiff images can be displayed directly onto IE and safari only.. no support of tiff images on chrome and firefox. you can encode the image and then display it on browser by decoding the encoded image to some other format. Hope this works for you

C# Ignore certificate errors?

Bypass SSL Certificate....

        HttpClientHandler clientHandler = new HttpClientHandler();
        clientHandler.ServerCertificateCustomValidationCallback = (sender, cert, chain, sslPolicyErrors) => { return true; };

        // Pass the handler to httpclient(from you are calling api)
        var client = new HttpClient(clientHandler)

How to check if the request is an AJAX request with PHP

You could try using a $_SESSION variable to make sure that a request was made from a browser. Otherwise, you could have the request sent through a database or file [server-side].

Git Bash won't run my python files?

This works great on win7

$ PATH=$PATH:/c/Python27/ $ python -V Python 2.7.12

Screenshot

jQuery set checkbox checked

Worked for me:

$checkbok.prop({checked: true});

When should I use curly braces for ES6 import?

Usually when you export a function you need to use the {}.

If you have

export const x

you use

import {x} from ''

If you use

export default const x

you need to use

import x from ''

Here you can change X to whatever variable you want.

Accessing the logged-in user in a template

{{ app.user.username|default('') }}

Just present login username for example, filter function default('') should be nice when user is NOT login by just avoid annoying error message.

How are people unit testing with Entity Framework 6, should you bother?

There is Effort which is an in memory entity framework database provider. I've not actually tried it... Haa just spotted this was mentioned in the question!

Alternatively you could switch to EntityFrameworkCore which has an in memory database provider built-in.

https://blog.goyello.com/2016/07/14/save-time-mocking-use-your-real-entity-framework-dbcontext-in-unit-tests/

https://github.com/tamasflamich/effort

I used a factory to get a context, so i can create the context close to its use. This seems to work locally in visual studio but not on my TeamCity build server, not sure why yet.

return new MyContext(@"Server=(localdb)\mssqllocaldb;Database=EFProviders.InMemory;Trusted_Connection=True;");

php create object without class

you can always use new stdClass(). Example code:

   $object = new stdClass();
   $object->property = 'Here we go';

   var_dump($object);
   /*
   outputs:

   object(stdClass)#2 (1) {
      ["property"]=>
      string(10) "Here we go"
    }
   */

Also as of PHP 5.4 you can get same output with:

$object = (object) ['property' => 'Here we go'];

How to zero pad a sequence of integers in bash so that all have the same width?

If you want N digits, add 10^N and delete the first digit.

for (( num=100; num<=105; num++ ))
do
  echo ${num:1:3}
done

Output:

01
02
03
04
05

SessionTimeout: web.xml vs session.maxInactiveInterval()

Now, i'm being told that this will terminate the session (or is it all sessions?) in the 15th minute of use, regardless their activity.

This is wrong. It will just kill the session when the associated client (webbrowser) has not accessed the website for more than 15 minutes. The activity certainly counts, exactly as you initially expected, seeing your attempt to solve this.

The HttpSession#setMaxInactiveInterval() doesn't change much here by the way. It does exactly the same as <session-timeout> in web.xml, with the only difference that you can change/set it programmatically during runtime. The change by the way only affects the current session instance, not globally (else it would have been a static method).


To play around and experience this yourself, try to set <session-timeout> to 1 minute and create a HttpSessionListener like follows:

@WebListener
public class HttpSessionChecker implements HttpSessionListener {

    public void sessionCreated(HttpSessionEvent event) {
        System.out.printf("Session ID %s created at %s%n", event.getSession().getId(), new Date());
    }

    public void sessionDestroyed(HttpSessionEvent event) {
        System.out.printf("Session ID %s destroyed at %s%n", event.getSession().getId(), new Date());
    }

}

(if you're not on Servlet 3.0 yet and thus can't use @WebListener, then register in web.xml as follows):

<listener>
    <listener-class>com.example.HttpSessionChecker</listener-class>
</listener>

Note that the servletcontainer won't immediately destroy sessions after exactly the timeout value. It's a background job which runs at certain intervals (e.g. 5~15 minutes depending on load and the servletcontainer make/type). So don't be surprised when you don't see destroyed line in the console immediately after exactly one minute of inactivity. However, when you fire a HTTP request on a timed-out-but-not-destroyed-yet session, it will be destroyed immediately.

See also:

Accessing a matrix element in the "Mat" object (not the CvMat object) in OpenCV C++

For cv::Mat_<T> mat just use mat(row, col)

Accessing elements of a matrix with specified type cv::Mat_< _Tp > is more comfortable, as you can skip the template specification. This is pointed out in the documentation as well.

code:

cv::Mat1d mat0 = cv::Mat1d::zeros(3, 4);
std::cout << "mat0:\n" << mat0 << std::endl;
std::cout << "element: " << mat0(2, 0) << std::endl;
std::cout << std::endl;

cv::Mat1d mat1 = (cv::Mat1d(3, 4) <<
    1, NAN, 10.5, NAN,
    NAN, -99, .5, NAN,
    -70, NAN, -2, NAN);
std::cout << "mat1:\n" << mat1 << std::endl;
std::cout << "element: " << mat1(0, 2) << std::endl;
std::cout << std::endl;

cv::Mat mat2 = cv::Mat(3, 4, CV_32F, 0.0);
std::cout << "mat2:\n" << mat2 << std::endl;
std::cout << "element: " << mat2.at<float>(2, 0) << std::endl;
std::cout << std::endl;

output:

mat0:
[0, 0, 0, 0;
 0, 0, 0, 0;
 0, 0, 0, 0]
element: 0

mat1:
[1, nan, 10.5, nan;
 nan, -99, 0.5, nan;
 -70, nan, -2, nan]
element: 10.5

mat2:
[0, 0, 0, 0;
 0, 0, 0, 0;
 0, 0, 0, 0]
element: 0

Dynamic SQL results into temp table in SQL Stored procedure

CREATE PROCEDURE dbo.pdpd_DynamicCall 
AS
DECLARE @SQLString_2 NVARCHAR(4000)
SET NOCOUNT ON
Begin
    --- Create global temp table
    CREATE TABLE ##T1 ( column_1 varchar(10) , column_2 varchar(100) )

    SELECT @SQLString_2 = 'INSERT INTO ##T1( column_1, column_2) SELECT column_1 = "123", column_2 = "MUHAMMAD IMRON"'
    SELECT @SQLString_2 = REPLACE(@SQLString_2, '"', '''')

    EXEC SP_EXECUTESQL @SQLString_2

    --- Test Display records
    SELECT * FROM ##T1

    --- Drop global temp table 
    IF OBJECT_ID('tempdb..##T1','u') IS NOT NULL
    DROP TABLE ##T1
End

How to use XPath preceding-sibling correctly

You don't need to go level up and use .. since all buttons are on the same level:

//button[contains(.,'Arcade Reader')]/preceding-sibling::button[@name='settings']

How to convert date to timestamp?

To convert (ISO) date to Unix timestamp, I ended up with a timestamp 3 characters longer than needed so my year was somewhere around 50k...

I had to devide it by 1000: new Date('2012-02-26').getTime() / 1000

Difference between "enqueue" and "dequeue"

Enqueue and Dequeue tend to be operations on a queue, a data structure that does exactly what it sounds like it does.

You enqueue items at one end and dequeue at the other, just like a line of people queuing up for tickets to the latest Taylor Swift concert (I was originally going to say Billy Joel but that would date me severely).

There are variations of queues such as double-ended ones where you can enqueue and dequeue at either end but the vast majority would be the simpler form:

           +---+---+---+
enqueue -> | 3 | 2 | 1 | -> dequeue
           +---+---+---+

That diagram shows a queue where you've enqueued the numbers 1, 2 and 3 in that order, without yet dequeuing any.


By way of example, here's some Python code that shows a simplistic queue in action, with enqueue and dequeue functions. Were it more serious code, it would be implemented as a class but it should be enough to illustrate the workings:

import random

def enqueue(lst, itm):
    lst.append(itm)        # Just add item to end of list.
    return lst             # And return list (for consistency with dequeue).

def dequeue(lst):
    itm = lst[0]           # Grab the first item in list.
    lst = lst[1:]          # Change list to remove first item.
    return (itm, lst)      # Then return item and new list.

# Test harness. Start with empty queue.

myList = []

# Enqueue or dequeue a bit, with latter having probability of 10%.

for _ in range(15):
    if random.randint(0, 9) == 0 and len(myList) > 0:
        (itm, myList) = dequeue(myList)
        print(f"Dequeued {itm} to give {myList}")
    else:
        itm = 10 * random.randint(1, 9)
        myList = enqueue(myList, itm)
        print(f"Enqueued {itm} to give {myList}")

# Now dequeue remainder of list.

print("========")
while len(myList) > 0:
    (itm, myList) = dequeue(myList)
    print(f"Dequeued {itm} to give {myList}")

A sample run of that shows it in operation:

Enqueued 70 to give [70]
Enqueued 20 to give [70, 20]
Enqueued 40 to give [70, 20, 40]
Enqueued 50 to give [70, 20, 40, 50]
Dequeued 70 to give [20, 40, 50]
Enqueued 20 to give [20, 40, 50, 20]
Enqueued 30 to give [20, 40, 50, 20, 30]
Enqueued 20 to give [20, 40, 50, 20, 30, 20]
Enqueued 70 to give [20, 40, 50, 20, 30, 20, 70]
Enqueued 20 to give [20, 40, 50, 20, 30, 20, 70, 20]
Enqueued 20 to give [20, 40, 50, 20, 30, 20, 70, 20, 20]
Dequeued 20 to give [40, 50, 20, 30, 20, 70, 20, 20]
Enqueued 80 to give [40, 50, 20, 30, 20, 70, 20, 20, 80]
Dequeued 40 to give [50, 20, 30, 20, 70, 20, 20, 80]
Enqueued 90 to give [50, 20, 30, 20, 70, 20, 20, 80, 90]
========
Dequeued 50 to give [20, 30, 20, 70, 20, 20, 80, 90]
Dequeued 20 to give [30, 20, 70, 20, 20, 80, 90]
Dequeued 30 to give [20, 70, 20, 20, 80, 90]
Dequeued 20 to give [70, 20, 20, 80, 90]
Dequeued 70 to give [20, 20, 80, 90]
Dequeued 20 to give [20, 80, 90]
Dequeued 20 to give [80, 90]
Dequeued 80 to give [90]
Dequeued 90 to give []

Get current time as formatted string in Go?

Use the time.Now() and time.Format() functions (as time.LocalTime() doesn't exist anymore as of Go 1.0.3)

t := time.Now()
fmt.Println(t.Format("20060102150405"))

Online demo (with date fixed in the past in the playground, never mind)