unique object identifier in javascript

jQuery code uses it's own data() method as such id.

var id = $.data(object);

At the backstage method data creates a very special field in object called "jQuery" + now() put there next id of a stream of unique ids like

id = elem[ expando ] = ++uuid;

I'd suggest you use the same method as John Resig obviously knows all there is about JavaScript and his method is based on all that knowledge.

Styling HTML email for Gmail

Gmail started basic support for style tags in the head area. Found nothing official yet but you can easily try it yourself.
It seems to ignore class and id selectors but basic element selectors work.

<!doctype html>
<html>
  <head>
    <style type="text/css">
      p{font-family:Tahoma,sans-serif;font-size:12px;margin:0}  
    </style>
  </head>
  <body>
    <p>Email content here</p>
  </body>
</html>

it will create a style tag in its own head area limited to the div containing the mail body

<style>div.m14623dcb877eef15 p{font-family:Tahoma,sans-serif;font-size:12px;margin:0}</style>

Hello World in Python

print("Hello, World!")

You are probably using Python 3.0, where print is now a function (hence the parenthesis) instead of a statement.

AttributeError: 'str' object has no attribute

The problem is in your playerMovement method. You are creating the string name of your room variables (ID1, ID2, ID3):

letsago = "ID" + str(self.dirDesc.values())

However, what you create is just a str. It is not the variable. Plus, I do not think it is doing what you think its doing:

>>>str({'a':1}.values())
'dict_values([1])'

If you REALLY needed to find the variable this way, you could use the eval function:

>>>foo = 'Hello World!'
>>>eval('foo')
'Hello World!'

or the globals function:

class Foo(object):
    def __init__(self):
        super(Foo, self).__init__()
    def test(self, name):
        print(globals()[name])

foo = Foo()
bar = 'Hello World!'
foo.text('bar')

However, instead I would strongly recommend you rethink you class(es). Your userInterface class is essentially a Room. It shouldn't handle player movement. This should be within another class, maybe GameManager or something like that.

How do I restrict an input to only accept numbers?

Using ng-pattern on the text field:

<input type="text"  ng-model="myText" name="inputName" ng-pattern="onlyNumbers">

Then include this on your controller

$scope.onlyNumbers = /^\d+$/;

How to import jquery using ES6 syntax?

webpack users, add the below to your plugins array.

let plugins = [
  // expose $ and jQuery to global scope.
  new webpack.ProvidePlugin({
    $: 'jquery',
    jQuery: 'jquery'
  })
];

Serializing list to JSON

You can use pure Python to do it:

import json
list = [1, 2, (3, 4)] # Note that the 3rd element is a tuple (3, 4)
json.dumps(list) # '[1, 2, [3, 4]]'

How do I convert 2018-04-10T04:00:00.000Z string to DateTime?

Update: Using `DateTimeFormat`, introduced in java 8:

The idea is to define two formats: one for the input format, and one for the output format. Parse with the input formatter, then format with the output formatter.

Your input format looks quite standard, except the trailing Z. Anyway, let's deal with this: "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'". The trailing 'Z' is the interesting part. Usually there's time zone data here, like -0700. So the pattern would be ...Z, i.e. without apostrophes.

The output format is way more simple: "dd-MM-yyyy". Mind the small y -s.

Here is the example code:

DateTimeFormatter inputFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.ENGLISH);
DateTimeFormatter outputFormatter = DateTimeFormatter.ofPattern("dd-MM-yyy", Locale.ENGLISH);
LocalDate date = LocalDate.parse("2018-04-10T04:00:00.000Z", inputFormatter);
String formattedDate = outputFormatter.format(date);
System.out.println(formattedDate); // prints 10-04-2018

Original answer - with old API `SimpleDateFormat`

SimpleDateFormat inputFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
SimpleDateFormat outputFormat = new SimpleDateFormat("dd-MM-yyyy");
Date date = inputFormat.parse("2018-04-10T04:00:00.000Z");
String formattedDate = outputFormat.format(date);
System.out.println(formattedDate); // prints 10-04-2018

How to include a font .ttf using CSS?

I know this is an old post but this solved my problem.

_x000D_

@font-face{_x000D_
  font-family: "Font Name";_x000D_
  src: url("../fonts/font-name.ttf") format("truetype");_x000D_
}

_x000D_

notice src:url("../fonts/font-name.ttf"); we use two periods to go back to the root directory and then into the fonts folder or wherever your file is located.

hope this helps someone down the line:) happy coding

Hash function for a string

First, it usually does not matter that much in practice. Most hash functions are "good enough".

But if you really care, you should know that it is a research subject by itself. There are thousand of papers about that. You can still get a PhD today by studying & designing hashing algorithms.

Your second hash function might be slightly better, because it probably should separate the string "ab" from the string "ba". On the other hand, it is probably less quick than the first hash function. It may, or may not, be relevant for your application.

I'll guess that hash functions used for genome strings are quite different than those used to hash family names in telephone databases. Perhaps even some string hash functions are better suited for German, than for English or French words.

Many software libraries give you good enough hash functions, e.g. Qt has qhash, and C++11 has std::hash in <functional>, Glib has several hash functions in C, and POCO has some hash function.

I quite often have hashing functions involving primes (see Bézout's identity) and xor, like e.g.

#define A 54059 /* a prime */
#define B 76963 /* another prime */
#define C 86969 /* yet another prime */
#define FIRSTH 37 /* also prime */
unsigned hash_str(const char* s)
{
   unsigned h = FIRSTH;
   while (*s) {
     h = (h * A) ^ (s[0] * B);
     s++;
   }
   return h; // or return h % C;
}

But I don't claim to be an hash expert. Of course, the values of A, B, C, FIRSTH should preferably be primes, but you could have chosen other prime numbers.

Look at some MD5 implementation to get a feeling of what hash functions can be.

Most good books on algorithmics have at least a whole chapter dedicated to hashing. Start with wikipages on hash function & hash table.

Non-resolvable parent POM for Could not find artifact and 'parent.relativePath' points at wrong local POM

In pom.xml file of the project,

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>X.X.X.RELEASE</version>
<relativePath> ../PROJECTNAME/pom.xml</relativePath>
</parent>

Pointing relativepath to the same MAVEN project POM file solved the issue for me.

How to append to New Line in Node.js

It looks like you're running this on Windows (given your H://log.txt file path).

Try using \r\n instead of just \n.

Honestly, \n is fine; you're probably viewing the log file in notepad or something else that doesn't render non-Windows newlines. Try opening it in a different viewer/editor (e.g. Wordpad).

How to fix java.net.SocketException: Broken pipe?

I'd the same problem while I was developing a simple Java application that listens on a specific TCP. Usually, I had no problem, but when I run some stress test I noticed that some connection broke with error socket write exception.

After Investigation I found a solution that solves my problem. I know this question is quite old, but I prefer to share my solution, someone can find it useful.

The problem was on ServerSocket creation. I read from Javadoc there is a default limit of 50 pending sockets. If you try opening another connection, these will be refused. The solution consist simply in change this default configuration at server side. In the following case, I create a Socket server that listen at TCP port 10_000 and accept max 200 pending sockets.

new Thread(() -> {
      try (ServerSocket serverSocket = new ServerSocket(10_000, 200)) {
        logger.info("Server starts listening on TCP port {}", port);

        while (true) {
          try {
            ClientHandler clientHandler = clientHandlerProvider.getObject(serverSocket.accept(), this);
            executor.execute(clientHandler::start);
          } catch (Exception e) {
            logger.error(e.getMessage());
          }
        }

      } catch (IOException | SecurityException | IllegalArgumentException e) {
        logger.error("Could not open server on TCP port {}. Reason: {}", port, e.getMessage());
      }
    }).start();

From Javadoc of ServerSocket:

The maximum queue length for incoming connection indications (a request to connect) is set to the backlog parameter. If a connection indication arrives when the queue is full, the connection is refused.

maxReceivedMessageSize and maxBufferSize in app.config

You need to do that on your binding, but you'll need to do it on both Client and Server. Something like:

<system.serviceModel>
    <bindings>
        <basicHttpBinding>
            <binding maxBufferSize="64000000" maxReceivedMessageSize="64000000" />
        </basicHttpBinding>
    </bindings>
</system.serviceModel>

Reporting Services export to Excel with Multiple Worksheets

On the group press F4 and look for the page name, on the properties and name your page this should solve your problem

How to identify a strong vs weak relationship on ERD?

In entity relationship modeling, solid lines represent strong relationships and dashed lines represent weak relationships.

How do I detect if I am in release or debug mode?

Due to the mixed comments about BuildConfig.DEBUG, I used the following to disable crashlytics (and analytics) in debug mode :

update /app/build.gradle

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.1"

    defaultConfig {
        applicationId "your.awesome.app"
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 100
        versionName "1.0.0"
        buildConfigField 'boolean', 'ENABLE_CRASHLYTICS', 'true'
    }
    buildTypes {
        debug {
            debuggable true
            minifyEnabled false
            buildConfigField 'boolean', 'ENABLE_CRASHLYTICS', 'false'
        }
        release {
            debuggable false
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

then, in your code you detect the ENABLE_CRASHLYTICS flag as follows:

    if (BuildConfig.ENABLE_CRASHLYTICS)
    {
        // enable crashlytics and answers (Crashlytics by default includes Answers)
        Fabric.with(this, new Crashlytics());
    }

use the same concept in your app and rename ENABLE_CRASHLYTICS to anything you want. I like this approach because I can see the flag in the configuration and I can control the flag.

How do I get the position selected in a RecyclerView?

I solved this way

class MyOnClickListener implements View.OnClickListener {
        @Override
        public void onClick(View v) {

            int itemPosition = mRecyclerView.getChildAdapterPosition(v);

            myResult = results.get(itemPosition);


        }
    }

And in the adapter

@Override
        public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
                                                       int viewType) {            
            View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_wifi, parent, false);
            v.setOnClickListener(new MyOnClickListener());
            ViewHolder vh = new ViewHolder(v);
            return vh;
        }

jQuery onclick toggle class name

It can even be made dependent to another attribute changes. like this:

$('.classA').toggleClass('classB', $('input').prop('disabled'));

In this case, classB are added each time the input is disabled

A more useful statusline in vim?

What I've found useful is to know which copy/paste buffer (register) is currently active: %{v:register}. Otherwise, my complete status line looks almost exactly like the standard line.

:set statusline=%<%f\ %h%m%r\ %y%=%{v:register}\ %-14.(%l,%c%V%)\ %P

How do I search for files in Visual Studio Code?

You can also press F1 to open the Command Palette and then remove the > via Backspace. Now you can search for files, too.

How to define custom sort function in javascript?

For Objects try this:

function sortBy(field) {
  return function(a, b) {
    if (a[field] > b[field]) {
      return -1;
    } else if (a[field] < b[field]) {
      return 1;
    }
    return 0;
  };
}

‘ant’ is not recognized as an internal or external command

Please follow these steps

In User Variables

Set VARIABLE NAME=ANT_HOME VARIABLE PATH =C:\Program Files\apache-ant-1.9.7

2.Edit User Variable PATH = %ANT_HOME%\bin

Go to System Variables
- Set Path =%ANT_HOME%\bin

Chrome violation : [Violation] Handler took 83ms of runtime

It seems you have found your solution, but still it will be helpful to others, on this page on point based on Chrome 59.

4.Note the red triangle in the top-right of the Animation Frame Fired event. Whenever you see a red triangle, it's a warning that there may be an issue related to this event.

If you hover on these triangle you can see those are the violation handler errors and as per point 4. yes there is some issue related to that event.

Is there any WinSCP equivalent for linux?

Just use gnome, just type in the address and away you go!

How to use XPath contains() here?

Paste my contains example here:

//table[contains(@class, "EC_result")]/tbody

java.util.NoSuchElementException - Scanner reading user input

the reason of the exception has been explained already, however the suggested solution isn't really the best.

You should create a class that keeps a Scanner as private using Singleton Pattern, that makes that scanner unique on your code.

Then you can implement the methods you need or you can create a getScanner ( not recommended ) and you can control it with a private boolean, something like alreadyClosed.

If you are not aware how to use Singleton Pattern, here's a example:

public class Reader {
    
    
    private Scanner reader;
    private static Reader singleton = null;
    private boolean alreadyClosed;
    
    private Reader() {
        alreadyClosed = false;
        reader = new Scanner(System.in);
    }
    
    public static Reader getInstance() {
        if(singleton == null) {
            singleton = new Reader();
        }
        return singleton;
    }
    
    public int nextInt() throws AlreadyClosedException {
        if(!alreadyClosed) {
            return reader.nextInt();
        }
        throw new AlreadyClosedException(); //Custom exception
    }
    
    public double nextDouble() throws AlreadyClosedException {
        if(!alreadyClosed) {
            return reader.nextDouble();
        }
        throw new AlreadyClosedException();
    }
    
    public String nextLine() throws AlreadyClosedException {
        if(!alreadyClosed) {
            return reader.nextLine();
        }
        throw new AlreadyClosedException();
    }
    
    public void close() {
        alreadyClosed = true;
        reader.close();
    }   
}

Count unique values in a column in Excel

I am using a spreadsheet with headers in row 1, data are in rows 2 and below.

IDs are in column A. To count how many different values there are I put this formula from row 2 to the end of the spreadsheet of the first available column [F in my case] : "=IF(A2=A1,F1+1,1)".

Then I use the following formula in a free cell: "=COUNTIF(F:F,1)". In this way I am sure every ID is counted.

Please note that IDs must be sorted, otherwise they will be counted more than once...but unlike array formulas it is very fast even with a 150000 rows spreadsheet.

How can I bind a background color in WPF/XAML?

Important:

Make sure you're using System.Windows.Media.Brush and not System.Drawing.Brush

They're not compatible and you'll get binding errors.

The color enumeration you need to use is also different

System.Windows.Media.Colors.Aquamarine (class name is Colors) <--- use this one System.Drawing.Color.Aquamarine (class name is Color)

If in doubt use Snoop and inspect the element's background property to look for binding errors - or just look in your debug log.

Windows 7, 64 bit, DLL problems

I had the same problem. After spending hours searching on the web, I found a solution for me.

I copied the file combase.dll file (C:\Windows\System32) to the release folder, and it resolved the problem.

How to destroy a JavaScript object?

While the existing answers have given solutions to solve the issue and the second half of the question, they do not provide an answer to the self discovery aspect of the first half of the question that is in bold:

"How can I see which variable causes memory overhead...?"

It may not have been as robust 3 years ago, but the Chrome Developer Tools "Profiles" section is now quite powerful and feature rich. The Chrome team has an insightful article on using it and thus also how garbage collection (GC) works in javascript, which is at the core of this question.

Since delete is basically the root of the currently accepted answer by Yochai Akoka, it's important to remember what delete does. It's irrelevant if not combined with the concepts of how GC works in the next two answers: if there's an existing reference to an object it's not cleaned up. The answers are more correct, but probably not as appreciated because they require more thought than just writing 'delete'. Yes, one possible solution may be to use delete, but it won't matter if there's another reference to the memory leak.

Another answer appropriately mentions circular references and the Chrome team documentation can provide much more clarity as well as the tools to verify the cause.

Since delete was mentioned here, it also may be useful to provide the resource Understanding Delete. Although it does not get into any of the actual solution which is really related to javascript's garbage collector.

The difference between fork(), vfork(), exec() and clone()

The fork(),vfork() and clone() all call the do_fork() to do the real work, but with different parameters.

asmlinkage int sys_fork(struct pt_regs regs)
{
    return do_fork(SIGCHLD, regs.esp, &regs, 0);
}

asmlinkage int sys_clone(struct pt_regs regs)
{
    unsigned long clone_flags;
    unsigned long newsp;

    clone_flags = regs.ebx;
    newsp = regs.ecx;
    if (!newsp)
        newsp = regs.esp;
    return do_fork(clone_flags, newsp, &regs, 0);
}
asmlinkage int sys_vfork(struct pt_regs regs)
{
    return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, &regs, 0);
}
#define CLONE_VFORK 0x00004000  /* set if the parent wants the child to wake it up on mm_release */
#define CLONE_VM    0x00000100  /* set if VM shared between processes */

SIGCHLD means the child should send this signal to its father when exit.

For fork, the child and father has the independent VM page table, but since the efficiency, fork will not really copy any pages, it just set all the writeable pages to readonly for child process. So when child process want to write something on that page, an page exception happen and kernel will alloc a new page cloned from the old page with write permission. That's called "copy on write".

For vfork, the virtual memory is exactly by child and father---just because of that, father and child can't be awake concurrently since they will influence each other. So the father will sleep at the end of "do_fork()" and awake when child call exit() or execve() since then it will own new page table. Here is the code(in do_fork()) that the father sleep.

if ((clone_flags & CLONE_VFORK) && (retval > 0))
down(&sem);
return retval;

Here is the code(in mm_release() called by exit() and execve()) which awake the father.

up(tsk->p_opptr->vfork_sem);

For sys_clone(), it is more flexible since you can input any clone_flags to it. So pthread_create() call this system call with many clone_flags:

Summary: the fork(),vfork() and clone() will create child processes with different mount of sharing resource with the father process. We also can say the vfork() and clone() can create threads(actually they are processes since they have independent task_struct) since they share the VM page table with father process.

Autowiring two beans implementing same interface - how to set default bean to autowire?

I'd suggest marking the Hibernate DAO class with @Primary, i.e. (assuming you used @Repository on HibernateDeviceDao):

@Primary
@Repository
public class HibernateDeviceDao implements DeviceDao

This way it will be selected as the default autowire candididate, with no need to autowire-candidate on the other bean.

Also, rather than using @Autowired @Qualifier, I find it more elegant to use @Resource for picking specific beans, i.e.

@Resource(name="jdbcDeviceDao")
DeviceDao deviceDao;

pretty-print JSON using JavaScript

Douglas Crockford's JSON in JavaScript library will pretty print JSON via the stringify method.

You may also find the answers to this older question useful: How can I pretty-print JSON in (unix) shell script?

Detecting when Iframe content has loaded (Cross browser)

For those using React, detecting a same-origin iframe load event is as simple as setting onLoad event listener on iframe element.

<iframe src={'path-to-iframe-source'} onLoad={this.loadListener} frameBorder={0} />

Parse string to DateTime in C#

The simple and straightforward answer -->

using System;

namespace DemoApp.App

{
public class TestClassDate
{
    public static DateTime GetDate(string string_date)
    {
        DateTime dateValue;
        if (DateTime.TryParse(string_date, out dateValue))
            Console.WriteLine("Converted '{0}' to {1}.", string_date, dateValue);
        else
            Console.WriteLine("Unable to convert '{0}' to a date.", string_date);
        return dateValue;
    }
    public static void Main()
    {
        string inString = "05/01/2009 06:32:00";
        GetDate(inString);
    }
}
}

/**
 * Output:
 * Converted '05/01/2009 06:32:00' to 5/1/2009 6:32:00 AM.
 * */

Interface vs Base class

Source: http://jasonroell.com/2014/12/09/interfaces-vs-abstract-classes-what-should-you-use/

C# is a wonderful language that has matured and evolved over the last 14 years. This is great for us developers because a mature language provides us with a plethora of language features that are at our disposal.

However, with much power becomes much responsibility. Some of these features can be misused, or sometimes it is hard to understand why you would choose to use one feature over another. Over the years, a feature that I have seen many developers struggle with is when to choose to use an interface or to choose to use an abstract class. Both have there advantages and disadvantages and the correct time and place to use each. But how to we decide???

Both provide for reuse of common functionality between types. The most obvious difference right away is that interfaces provide no implementation for their functionality whereas abstract classes allow you to implement some “base” or “default” behavior and then have the ability to “override” this default behavior with the classes derived types if necessary.

This is all well and good and provides for great reuse of code and adheres to the DRY (Don’t Repeat Yourself) principle of software development. Abstract classes are great to use when you have an “is a” relationship.

For example: A golden retriever “is a” type of dog. So is a poodle. They both can bark, as all dogs can. However, you might want to state that the poodle park is significantly different than the “default” dog bark. Therefor, it could make sense for you to implement something as follows:

public abstract class Dog
{
      public virtual void Bark()
      {
        Console.WriteLine("Base Class implementation of Bark");
      }
}

public class GoldenRetriever : Dog
{
   // the Bark method is inherited from the Dog class
}

public class Poodle : Dog
{
  // here we are overriding the base functionality of Bark with our new implementation
  // specific to the Poodle class
  public override void Bark()
  {
     Console.WriteLine("Poodle's implementation of Bark");
  }
}

// Add a list of dogs to a collection and call the bark method.

void Main()
{
    var poodle = new Poodle();
    var goldenRetriever = new GoldenRetriever();

    var dogs = new List<Dog>();
    dogs.Add(poodle);
    dogs.Add(goldenRetriever);

    foreach (var dog in dogs)
    {
       dog.Bark();
    }
}

// Output will be:
// Poodle's implementation of Bark
// Base Class implementation of Bark

//

As you can see, this would be a great way to keep your code DRY and allow for the base class implementation be called when any of the types can just rely on the default Bark instead of a special case implementation. The classes like GoldenRetriever, Boxer, Lab could all could inherit the “default” (bass class) Bark at no charge just because they implement the Dog abstract class.

But I’m sure you already knew that.

You are here because you want to understand why you might want to choose an interface over an abstract class or vice versa. Well one reason you may want to choose an interface over an abstract class is when you don’t have or want to prevent a default implementation. This is usually because the types that are implementing the interface not related in an “is a” relationship. Actually, they don’t have to be related at all except for the fact that each type “is able” or has “the ablity” to do something or have something.

Now what the heck does that mean? Well, for example: A human is not a duck…and a duck is not a human. Pretty obvious. However, both a duck and a human have “the ability” to swim (given that the human passed his swimming lessons in 1st grade :) ). Also, since a duck is not a human or vice versa, this is not an “is a” realationship, but instead an “is able” relationship and we can use an interface to illustrate that:

// Create ISwimable interface
public interface ISwimable
{
      public void Swim();
}

// Have Human implement ISwimable Interface
public class Human : ISwimable

     public void Swim()
     {
        //Human's implementation of Swim
        Console.WriteLine("I'm a human swimming!");
     }

// Have Duck implement ISwimable interface
public class Duck: ISwimable
{
     public void Swim()
     {
          // Duck's implementation of Swim
          Console.WriteLine("Quack! Quack! I'm a Duck swimming!")
     }
}

//Now they can both be used in places where you just need an object that has the ability "to swim"

public void ShowHowYouSwim(ISwimable somethingThatCanSwim)
{
     somethingThatCanSwim.Swim();
}

public void Main()
{
      var human = new Human();
      var duck = new Duck();

      var listOfThingsThatCanSwim = new List<ISwimable>();

      listOfThingsThatCanSwim.Add(duck);
      listOfThingsThatCanSwim.Add(human);

      foreach (var something in listOfThingsThatCanSwim)
      {
           ShowHowYouSwim(something);
      }
}

 // So at runtime the correct implementation of something.Swim() will be called
 // Output:
 // Quack! Quack! I'm a Duck swimming!
 // I'm a human swimming!

Using interfaces like the code above will allow you to pass an object into a method that “is able” to do something. The code doesn’t care how it does it…All it knows is that it can call the Swim method on that object and that object will know which behavior take at run-time based on its type.

Once again, this helps your code stay DRY so that you would not have to write multiple methods that are calling the object to preform the same core function (ShowHowHumanSwims(human), ShowHowDuckSwims(duck), etc.)

Using an interface here allows the calling methods to not have to worry about what type is which or how the behavior is implemented. It just knows that given the interface, each object will have to have implemented the Swim method so it is safe to call it in its own code and allow the behavior of the Swim method be handled within its own class.

Summary:

So my main rule of thumb is use an abstract class when you want to implement a “default” functionality for a class hierarchy or/and the classes or types you are working with share a “is a” relationship (ex. poodle “is a” type of dog).

On the other hand use an interface when you do not have an “is a” relationship but have types that share “the ability” to do something or have something (ex. Duck “is not” a human. However, duck and human share “the ability” to swim).

Another difference to note between abstract classes and interfaces is that a class can implement one to many interfaces but a class can only inherit from ONE abstract class (or any class for that matter). Yes, you can nest classes and have an inheritance hierarchy (which many programs do and should have) but you cannot inherit two classes in one derived class definition (this rule applies to C#. In some other languages you are able to do this, usually only because of the lack of interfaces in these languages).

Also remember when using interfaces to adhere to the Interface Segregation Principle (ISP). ISP states that no client should be forced to depend on methods it does not use. For this reason interfaces should be focused on specific tasks and are usually very small (ex. IDisposable, IComparable ).

Another tip is if you are developing small, concise bits of functionality, use interfaces. If you are designing large functional units, use an abstract class.

Hope this clears things up for some people!

Also if you can think of any better examples or want to point something out, please do so in the comments below!

How do I load an org.w3c.dom.Document from XML in a string?

To manipulate XML in Java, I always tend to use the Transformer API:

import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.stream.StreamSource;

public static Document loadXMLFrom(String xml) throws TransformerException {
    Source source = new StreamSource(new StringReader(xml));
    DOMResult result = new DOMResult();
    TransformerFactory.newInstance().newTransformer().transform(source , result);
    return (Document) result.getNode();
}

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". error

Had similar error with the same result with Gradle and was able to solve it by following:

//compile 'org.slf4j:slf4j-api:1.7.1'
compile group: 'org.apache.logging.log4j', name: 'log4j-api', version: '2.1'
compile group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.1'
compile group: 'org.apache.logging.log4j', name: 'log4j-slf4j-impl', version: '2.1'

Out-commented line is the one which caused the error output. I believe you can transfer this to Maven.

How to get a variable type in Typescript?

For :

abc:number|string;

Use the JavaScript operator typeof:

if (typeof abc === "number") {
    // do something
}

TypeScript understands typeof

This is called a typeguard.

For classes you would use instanceof e.g.

class Foo {}
class Bar {} 

// Later
if (fooOrBar instanceof Foo){
  // TypeScript now knows that `fooOrBar` is `Foo`
}

There are also other type guards e.g. in etc https://basarat.gitbooks.io/typescript/content/docs/types/typeGuard.html

Real time data graphing on a line chart with html5

I believe this is exactly what you're looking for:

http://www.highcharts.com/demo/dynamic-update

Open source (although a license is required for commercial websites), cross device/browser, fast.

Make code in LaTeX look nice

It turns out that lstlisting is able to format code nicely, but requires a lot of tweaking.

Wikibooks has a good example for the parameters you can tweak.

SQLDataReader Row Count

SQLDataReaders are forward-only. You're essentially doing this:

count++;  // initially 1
.DataBind(); //consuming all the records

//next iteration on
.Read()
//we've now come to end of resultset, thanks to the DataBind()
//count is still 1

You could do this instead:

if (reader.HasRows)
{
    rep.DataSource = reader;
    rep.DataBind();
}
int count = rep.Items.Count; //somehow count the num rows/items `rep` has.

Testing two JSON objects for equality ignoring child order in Java

I know it is usually considered only for testing but you could use the Hamcrest JSON comparitorSameJSONAs in Hamcrest JSON.

Hamcrest JSON SameJSONAs

What is Unicode, UTF-8, UTF-16?

Unicode is a fairly complex standard. Don’t be too afraid, but be prepared for some work! [2]

Because a credible resource is always needed, but the official report is massive, I suggest reading the following:

The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) An introduction by Joel Spolsky, Stack Exchange CEO.
To the BMP and beyond! A tutorial by Eric Muller, Technical Director then, Vice President later, at The Unicode Consortium. (first 20 slides and you are done)

A brief explanation:

Computers read bytes and people read characters, so we use encoding standards to map characters to bytes. ASCII was the first widely used standard, but covers only Latin (7 bits/character can represent 128 different characters). Unicode is a standard with the goal to cover all possible characters in the world (can hold up to 1,114,112 characters, meaning 21 bits/character max. Current Unicode 8.0 specifies 120,737 characters in total, and that's all).

The main difference is that an ASCII character can fit to a byte (8 bits), but most Unicode characters cannot. So encoding forms/schemes (like UTF-8 and UTF-16) are used, and the character model goes like this:

Every character holds an enumerated position from 0 to 1,114,111 (hex: 0-10FFFF) called code point.
An encoding form maps a code point to a code unit sequence. A code unit is the way you want characters to be organized in memory, 8-bit units, 16-bit units and so on. UTF-8 uses 1 to 4 units of 8 bits, and UTF-16 uses 1 or 2 units of 16 bits, to cover the entire Unicode of 21 bits max. Units use prefixes so that character boundaries can be spotted, and more units mean more prefixes that occupy bits. So, although UTF-8 uses 1 byte for the Latin script it needs 3 bytes for later scripts inside Basic Multilingual Plane, while UTF-16 uses 2 bytes for all these. And that's their main difference.
Lastly, an encoding scheme (like UTF-16BE or UTF-16LE) maps (serializes) a code unit sequence to a byte sequence.

character: p
code point: U+03C0
encoding forms (code units):
UTF-8: CF 80
UTF-16: 03C0
encoding schemes (bytes):
UTF-8: CF 80
UTF-16BE: 03 C0
UTF-16LE: C0 03

Tip: a hex digit represents 4 bits, so a two-digit hex number represents a byte
Also take a look at Plane maps in Wikipedia to get a feeling of the character set layout

loop through json array jquery

you could also change from the .get() method to the .getJSON() method, jQuery will then parse the string returned as data to a javascript object and/or array that you can then reference like any other javascript object/array.

using your code above, if you changed .get to .getJSON, you should get an alert of [object Object] for each element in the array. If you changed the alert to alert(item.name) you will get the names.

Make a Bash alias that takes a parameter?

Functions are indeed almost always the answer as already amply contributed and confirmed by this quote from the man page: "For almost every purpose, aliases are superseded by shell functions."

For completeness and because this can be useful (marginally more lightweight syntax) it could be noted that when the parameter(s) follow the alias, they can still be used (although this wouldn't address the OP's requirement). This is probably easiest to demonstrate with an example:

alias ssh_disc='ssh -O stop'

allows me to type smth like ssh_disc myhost, which gets expanded as expected as: ssh -O stop myhost

This can be useful for commands which take complex arguments (my memory isn't what it use t be anymore...)

What is the meaning of "POSIX"?

In 1985, individuals from companies throughout the computer industry joined together to develop the POSIX (Portable Operating System Interface for Computer Environments) standard, which is based largely on the UNIX System V Interface Definition (SVID) and other earlier standardization efforts. These efforts were spurred by the U.S. government, which needed a standard computing environment to minimize its training and procurement costs. Released in 1988, POSIX is a group of IEEE standards that define the API, shell, and utility interfaces for an operating system. Although aimed at UNIX-like systems, the standards can apply to any compatible operating system. Now that these stan- dards have gained acceptance, software developers are able to develop applications that run on all conforming versions of UNIX, Linux, and other operating systems.

From the book: A Practical Guide To Linux

HTML Tags in Javascript Alert() method

alert() doesn't support HTML, but you have some alternatives to format your message.

You can use Unicode characters as others stated, or you can make use of the ES6 Template literals. For example:

...
.catch(function (error) {
  const alertMessage = `Error retrieving resource. Please make sure:
    • the resource server is accessible
    • you're logged in

    Error: ${error}`;
  window.alert(alertMessage);
}

Output:

As you can see, it maintains the line breaks and spaces that we included in the variable, with no extra characters.

HTML/CSS: how to put text both right and left aligned in a paragraph

Ok what you probably want will be provide to you by result of:

in CSS:

div { column-count: 2; }
in html:

<div> some text, bla bla bla </div>

In CSS you make div to split your paragraph on to column, you can make them 3, 4...

If you want to have many differend paragraf like that, then put id or class in your div:

Reset IntelliJ UI to Default

check, if this works for you.

File -> Settings -> (type appe in search box) and select Appearance -> Select Intellij from dropdown option of Theme on the right (under UI Options).

Hope this helps someone.

Change values of select box of "show 10 entries" of jquery datatable

$(document).ready(function() {
    $('#example').dataTable( {
    "aLengthMenu": [[25, 50, 75, -1], [25, 50, 75, "All"]],
    "pageLength": 25
    } );
} );

aLengthMenu : This parameter allows you to readily specify the entries in the length drop down menu that DataTables shows when pagination is enabled. It can be either a 1D array of options which will be used for both the displayed option and the value, or a 2D array which will use the array in the first position as the value, and the array in the second position as the displayed options (useful for language strings such as 'All').

Update

Since DataTables v1.10, the options you are looking for are pageLength and lengthMenu

SQL: How do I SELECT only the rows with a unique value on certain column?

Updated to use your newly provided data:

The solutions using the original data may be found at the end of this answer.

Using your new data:

DECLARE  @T TABLE( [contract] INT, project INT, activity INT )
INSERT INTO @T VALUES( 1000,    8000,    10 )
INSERT INTO @T VALUES( 1000,    8000,    20 )
INSERT INTO @T VALUES( 1000,    8001,    10 )
INSERT INTO @T VALUES( 2000,    9000,    49 )
INSERT INTO @T VALUES( 2000,    9001,    49 )
INSERT INTO @T VALUES( 3000,    9000,    79 )
INSERT INTO @T VALUES( 3000,    9000,    78 )

SELECT DISTINCT [contract], activity FROM @T AS A WHERE
    (SELECT COUNT( DISTINCT activity ) 
     FROM @T AS B WHERE B.[contract] = A.[contract]) = 1

returns: 2000, 49

Solutions using original data

WARNING: The following solutions use the data previously given in the question and may not make sense for the current question. I have left them attached for completeness only.

SELECT Col1, Count( col1 ) AS count FROM table 
GROUP BY col1
HAVING count > 1

This should get you a list of all the values in col1 that are not distinct. You can place this in a table var or temp table and join against it.

Here is an example using a sub-query:

DECLARE @t TABLE( col1 VARCHAR(1), col2 VARCHAR(1), col3 VARCHAR(1) )

INSERT INTO @t VALUES( 'A', 'B', 'C' );
INSERT INTO @t VALUES( 'D', 'E', 'F' );
INSERT INTO @t VALUES( 'A', 'J', 'K' );
INSERT INTO @t VALUES( 'G', 'H', 'H' );

SELECT * FROM @t

SELECT col1, col2 FROM @t WHERE col1 NOT IN 
    (SELECT col1 FROM @t AS t GROUP BY col1 HAVING COUNT( col1 ) > 1)

This returns:

D   E
G   H

And another method that users a temp table and join:

DECLARE @t TABLE( col1 VARCHAR(1), col2 VARCHAR(1), col3 VARCHAR(1) )

INSERT INTO @t VALUES( 'A', 'B', 'C' );
INSERT INTO @t VALUES( 'D', 'E', 'F' );
INSERT INTO @t VALUES( 'A', 'J', 'K' );
INSERT INTO @t VALUES( 'G', 'H', 'H' );

SELECT * FROM @t

DROP TABLE #temp_table  
SELECT col1 INTO #temp_table
    FROM @t AS t GROUP BY col1 HAVING COUNT( col1 ) = 1

SELECT t.col1, t.col2 FROM @t AS t
    INNER JOIN #temp_table AS tt ON t.col1 = tt.col1

Also returns:

D   E
G   H

Can't ping a local VM from the host

I had a similar issue. You won't be able to ping the VM's from external devices if using NAT setting from within VMware's networking options. I switched to bridged connection so that the guest virtual machine will get it's own IP address and and then I added a second adapter set to NAT for the guest to get to the Internet.

How can I remove the extension of a filename in a shell script?

My recommendation is to use basename.
It is by default in Ubuntu, visually simple code and deal with majority of cases.

Here are some sub-cases to deal with spaces and multi-dot/sub-extension:

pathfile="../space fld/space -file.tar.gz"
echo ${pathfile//+(*\/|.*)}

It usually get rid of extension from first ., but fail in our .. path

echo **"$(basename "${pathfile%.*}")"**  
space -file.tar     # I believe we needed exatly that

Here is an important note:

I used double quotes inside double quotes to deal with spaces. Single quote will not pass due to texting the $. Bash is unusual and reads "second "first" quotes" due to expansion.

However, you still need to think of .hidden_files

hidden="~/.bashrc"
echo "$(basename "${hidden%.*}")"  # will produce "~" !!!

not the expected "" outcome. To make it happen use $HOME or /home/user_path/
because again bash is "unusual" and don't expand "~" (search for bash BashPitfalls)

hidden2="$HOME/.bashrc" ;  echo '$(basename "${pathfile%.*}")'

What does "exited with code 9009" mean during this build?

Check the spelling. I was trying to call an executable but had the name misspelled and it gave me the exited with code 9009 message.

how to make jni.h be found?

In case you are on Ubuntu:

#X means 6,7,8...
apt install openjdk-X-jdk

Android: how to parse URL String with spaces to URI object?

You should in fact URI-encode the "invalid" characters. Since the string actually contains the complete URL, it's hard to properly URI-encode it. You don't know which slashes / should be taken into account and which not. You cannot predict that on a raw String beforehand. The problem really needs to be solved at a higher level. Where does that String come from? Is it hardcoded? Then just change it yourself accordingly. Does it come in as user input? Validate it and show error, let the user solve itself.

At any way, if you can ensure that it are only the spaces in URLs which makes it invalid, then you can also just do a string-by-string replace with %20:

URI uri = new URI(string.replace(" ", "%20"));

Or if you can ensure that it's only the part after the last slash which needs to be URI-encoded, then you can also just do so with help of android.net.Uri utility class:

int pos = string.lastIndexOf('/') + 1;
URI uri = new URI(string.substring(0, pos) + Uri.encode(string.substring(pos)));

Do note that URLEncoder is insuitable for the task as it's designed to encode query string parameter names/values as per application/x-www-form-urlencoded rules (as used in HTML forms). See also Java URL encoding of query string parameters.

How to convert empty spaces into null values, using SQL Server?

I solved a similar problem using NULLIF function:

UPDATE table 
SET col1 = NULLIF(col1, '')

From the T-SQL reference:

NULLIF returns the first expression if the two expressions are not equal. If the expressions are equal, NULLIF returns a null value of the type of the first expression.

Protecting cells in Excel but allow these to be modified by VBA script

~~I don't think you can set any part of the sheet to be editable only by VBA~~, but you can do something that has basically the same effect -- you can unprotect the worksheet in VBA before you need to make changes:

wksht.Unprotect()

and re-protect it after you're done:

wksht.Protect()

Edit: Looks like this workaround may have solved Dheer's immediate problem, but for anyone who comes across this question/answer later, I was wrong about the first part of my answer, as Joe points out below. You can protect a sheet to be editable by VBA-only, but it appears the "UserInterfaceOnly" option can only be set when calling "Worksheet.Protect" in code.

Best HTML5 markup for sidebar

Look at the following example, from the HTML5 specification about aside.

It makes clear that what currently is recommended (October 2012) it is to group widgets inside aside elements. Then, each widget is whatever best represents it, a nav, a serie of blockquotes, etc

The following extract shows how aside can be used for blogrolls and other side content on a blog:

<body>
 <header>
  <h1>My wonderful blog</h1>
  <p>My tagline</p>
 </header>
 <aside>
  <!-- this aside contains two sections that are tangentially related
  to the page, namely, links to other blogs, and links to blog posts
  from this blog -->
  <nav>
   <h1>My blogroll</h1>
   <ul>
    <li><a href="http://blog.example.com/">Example Blog</a>
   </ul>
  </nav>
  <nav>
   <h1>Archives</h1>
   <ol reversed>
    <li><a href="/last-post">My last post</a>
    <li><a href="/first-post">My first post</a>
   </ol>
  </nav>
 </aside>
 <aside>
  <!-- this aside is tangentially related to the page also, it
  contains twitter messages from the blog author -->
  <h1>Twitter Feed</h1>
  <blockquote cite="http://twitter.example.net/t31351234">
   I'm on vacation, writing my blog.
  </blockquote>
  <blockquote cite="http://twitter.example.net/t31219752">
   I'm going to go on vacation soon.
  </blockquote>
 </aside>
 <article>
  <!-- this is a blog post -->
  <h1>My last post</h1>
  <p>This is my last post.</p>
  <footer>
   <p><a href="/last-post" rel=bookmark>Permalink</a>
  </footer>
 </article>
 <article>
  <!-- this is also a blog post -->
  <h1>My first post</h1>
  <p>This is my first post.</p>
  <aside>
   <!-- this aside is about the blog post, since it's inside the
   <article> element; it would be wrong, for instance, to put the
   blogroll here, since the blogroll isn't really related to this post
   specifically, only to the page as a whole -->
   <h1>Posting</h1>
   <p>While I'm thinking about it, I wanted to say something about
   posting. Posting is fun!</p>
  </aside>
  <footer>
   <p><a href="/first-post" rel=bookmark>Permalink</a>
  </footer>
 </article>
 <footer>
  <nav>
   <a href="/archives">Archives</a> —
   <a href="/about">About me</a> —
   <a href="/copyright">Copyright</a>
  </nav>
 </footer>
</body>

Regex to get the words after matching string

Here's a quick Perl script to get what you need. It needs some whitespace chomping.

#!/bin/perl

$sample = <<END;
Subject:
  Security ID:        S-1-5-21-3368353891-1012177287-890106238-22451
  Account Name:       ChamaraKer
  Account Domain:     JIC
  Logon ID:       0x1fffb

Object:
  Object Server:  Security
  Object Type:    File
  Object Name:    D:\\ApacheTomcat\\apache-tomcat-6.0.36\\logs\\localhost.2013- 07-01.log
  Handle ID:  0x11dc
END

my @sample_lines = split /\n/, $sample;
my $path;

foreach my $line (@sample_lines) {
  ($path) = $line =~ m/Object Name:([^s]+)/g;
  if($path) {
    print $path . "\n";
  }
}

Java client certificates over HTTPS/SSL

While not recommended, you can also disable SSL cert validation alltogether:

import javax.net.ssl.*;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;

public class SSLTool {

  public static void disableCertificateValidation() {
    // Create a trust manager that does not validate certificate chains
    TrustManager[] trustAllCerts = new TrustManager[] { 
      new X509TrustManager() {
        public X509Certificate[] getAcceptedIssuers() { 
          return new X509Certificate[0]; 
        }
        public void checkClientTrusted(X509Certificate[] certs, String authType) {}
        public void checkServerTrusted(X509Certificate[] certs, String authType) {}
    }};

    // Ignore differences between given hostname and certificate hostname
    HostnameVerifier hv = new HostnameVerifier() {
      public boolean verify(String hostname, SSLSession session) { return true; }
    };

    // Install the all-trusting trust manager
    try {
      SSLContext sc = SSLContext.getInstance("SSL");
      sc.init(null, trustAllCerts, new SecureRandom());
      HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
      HttpsURLConnection.setDefaultHostnameVerifier(hv);
    } catch (Exception e) {}
  }
}

How to get value by key from JObject?

This should help -

var json = "{'@STARTDATE': '2016-02-17 00:00:00.000',  '@ENDDATE': '2016-02-18 23:59:00.000' }";
var fdate = JObject.Parse(json)["@STARTDATE"];

How to find out when a particular table was created in Oracle?

You can query the data dictionary/catalog views to find out when an object was created as well as the time of last DDL involving the object (example: alter table)

select * 
  from all_objects 
 where owner = '<name of schema owner>'
   and object_name = '<name of table>'

The column "CREATED" tells you when the object was created. The column "LAST_DDL_TIME" tells you when the last DDL was performed against the object.

As for when a particular row was inserted/updated, you can use audit columns like an "insert_timestamp" column or use a trigger and populate an audit table

how to set the background image fit to browser using html

HTML

<img src="images/bg.jpg" id="bg" alt="">

CSS

#bg {
  position: fixed; 
  top: 0; 
  left: 0; 

  /* Preserve aspet ratio */
  min-width: 100%;
  min-height: 100%;
}

How can I change property names when serializing with Json.net?

There is still another way to do it, which is using a particular NamingStrategy, which can be applied to a class or a property by decorating them with [JSonObject] or [JsonProperty].

There are predefined naming strategies like CamelCaseNamingStrategy, but you can implement your own ones.

The implementation of different naming strategies can be found here: https://github.com/JamesNK/Newtonsoft.Json/tree/master/Src/Newtonsoft.Json/Serialization

What is the difference between CMD and ENTRYPOINT in a Dockerfile?

CMD:

CMD ["executable","param1","param2"]: ["executable","param1","param2"] is the first process.
CMD command param1 param2: /bin/sh -c CMD command param1 param2 is the first process. CMD command param1 param2 is forked from the first process.
CMD ["param1","param2"]: This form is used to provide default arguments for ENTRYPOINT.

ENTRYPOINT (The following list does not consider the case where CMD and ENTRYPOINT are used together):

ENTRYPOINT ["executable", "param1", "param2"]: ["executable", "param1", "param2"] is the first process.
ENTRYPOINT command param1 param2: /bin/sh -c command param1 param2 is the first process. command param1 param2 is forked from the first process.

As creack said, CMD was developed first. Then ENTRYPOINT was developed for more customization. Since they are not designed together, there are some functionality overlaps between CMD and ENTRYPOINT, which often confuse people.

How to disable the parent form when a child form is active?

For me this work for example here what happen is the main menu will be disabled when you open the registration form.

 frmUserRegistration frmMainMenu = new frmUserRegistration();
    frmMainMenu.ShowDialog(this);

Error: TypeError: $(...).dialog is not a function

if some reason two versions of jQuery are loaded (which is not recommended), calling $.noConflict(true) from the second version will return the globally scoped jQuery variables to those of the first version.

Some times it could be issue with older version (or not stable version) of JQuery files

Solution use $.noConflict();

<script src="other_lib.js"></script>
<script src="jquery.js"></script>
<script>
$.noConflict();
jQuery( document ).ready(function( $ ) {
   $("#opener").click(function() {
            $("#dialog1").dialog('open');
    });
});
// Code that uses other library's $ can follow here.
</script>

Apply style ONLY on IE

A bit late on this one but this worked perfectly for me when trying to hide the background for IE6 & 7

.myclass{ 
    background-image: url("images/myimg.png");
    background-position: right top;
    background-repeat: no-repeat;
    background-size: 22px auto;
    padding-left: 48px;
    height: 42px;
    _background-image: none;
    *background-image: none;
}

I got this hack via: http://briancray.com/posts/target-ie6-and-ie7-with-only-1-extra-character-in-your-css/

#myelement
{
    color: #999; /* shows in all browsers */
    *color: #999; /* notice the * before the property - shows in IE7 and below */
    _color: #999; /* notice the _ before the property - shows in IE6 and below */
}

Need to find element in selenium by css

Only using class names is not sufficient in your case.

By.cssSelector(".ban") has 15 matching nodes
By.cssSelector(".hot") has 11 matching nodes
By.cssSelector(".ban.hot") has 5 matching nodes

Therefore you need more restrictions to narrow it down. Option 1 and 2 below are available for css selector, 1 might be the one that suits your needs best.

Option 1: Using list items' index (CssSelector or XPath)

Limitations

Not stable enough if site's structure changes

Example:

driver.FindElement(By.CssSelector("#rightbar > .menu > li:nth-of-type(3) > h5"));
driver.FindElement(By.XPath("//*[@id='rightbar']/ul/li[3]/h5"));

Option 2: Using Selenium's FindElements, then index them. (CssSelector or XPath)

Limitations

Not stable enough if site's structure changes
Not the native selector's way

Example:

// note that By.CssSelector(".ban.hot") and //*[contains(@class, 'ban hot')] are different, but doesn't matter in your case
IList<IWebElement> hotBanners = driver.FindElements(By.CssSelector(".ban.hot"));
IWebElement banUsStates = hotBanners[3];

Option 3: Using text (XPath only)

Limitations

Not for multilanguage sites
Only for XPath, not for Selenium's CssSelector

Example:

driver.FindElement(By.XPath("//h5[contains(@class, 'ban hot') and text() = 'us states']"));

Option 4: Index the grouped selector (XPath only)

Limitations

Not stable enough if site's structure changes
Only for XPath, not CssSelector

Example:

driver.FindElement(By.XPath("(//h5[contains(@class, 'ban hot')])[3]"));

Option 5: Find the hidden list items link by href, then traverse back to h5 (XPath only)

Limitations

Only for XPath, not CssSelector
Low performance
Tricky XPath

Example:

driver.FindElement(By.XPath(".//li[.//ul/li/a[contains(@href, 'geo.craigslist.org/iso/us/al')]]/h5"));

No connection could be made because the target machine actively refused it 127.0.0.1

After six days I find the answer which make me crazy! The answer is disable proxy at web.config file:

<system.net>
  <defaultProxy> 
    <proxy usesystemdefault="False"/> 
  </defaultProxy>
</system.net>

How to detect when an @Input() value changes in Angular?

You could also just pass an EventEmitter as Input. Not quite sure if this is best practice tho...

CategoryComponent.ts:

categoryIdEvent: EventEmitter<string> = new EventEmitter<>();

- OTHER CODE -

setCategoryId(id) {
 this.category.id = id;
 this.categoryIdEvent.emit(this.category.id);
}

CategoryComponent.html:

<video-list *ngIf="category" [categoryId]="categoryIdEvent"></video-list>

And in VideoListComponent.ts:

@Input() categoryIdEvent: EventEmitter<string>
....
ngOnInit() {
 this.categoryIdEvent.subscribe(newID => {
  this.categoryId = newID;
 }
}

Can I execute a function after setState is finished updating?

render will be called every time you setState to re-render the component if there are changes. If you move your call to drawGrid there rather than calling it in your update* methods, you shouldn't have a problem.

If that doesn't work for you, there is also an overload of setState that takes a callback as a second parameter. You should be able to take advantage of that as a last resort.

vba listbox multicolumn add

Simplified example (with counter):

With Me.lstbox
    .ColumnCount = 2
    .ColumnWidths = "60;60"
    .AddItem
    .List(i, 0) = Company_ID
    .List(i, 1) = Company_name 
    i = i + 1

end with

Make sure to start the counter with 0, not 1 to fill up a listbox.

Any way to generate ant build.xml file automatically from Eclipse?

I'm the one who donated the Ant export filter to Eclipse. I added the auto export feature, but only to my personal plug-in eclipse2ant, which I still maintain to coordinate bug fixes.

Unfortunately I have no time to merge it to the official Eclipse builds.

Execute a command line binary with Node.js

For even newer version of Node.js (v8.1.4), the events and calls are similar or identical to older versions, but it's encouraged to use the standard newer language features. Examples:

For buffered, non-stream formatted output (you get it all at once), use child_process.exec:

const { exec } = require('child_process');
exec('cat *.js bad_file | wc -l', (err, stdout, stderr) => {
  if (err) {
    // node couldn't execute the command
    return;
  }

  // the *entire* stdout and stderr (buffered)
  console.log(`stdout: ${stdout}`);
  console.log(`stderr: ${stderr}`);
});

You can also use it with Promises:

const util = require('util');
const exec = util.promisify(require('child_process').exec);

async function ls() {
  const { stdout, stderr } = await exec('ls');
  console.log('stdout:', stdout);
  console.log('stderr:', stderr);
}
ls();

If you wish to receive the data gradually in chunks (output as a stream), use child_process.spawn:

const { spawn } = require('child_process');
const child = spawn('ls', ['-lh', '/usr']);

// use child.stdout.setEncoding('utf8'); if you want text chunks
child.stdout.on('data', (chunk) => {
  // data from standard output is here as buffers
});

// since these are streams, you can pipe them elsewhere
child.stderr.pipe(dest);

child.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Both of these functions have a synchronous counterpart. An example for child_process.execSync:

const { execSync } = require('child_process');
// stderr is sent to stderr of parent process
// you can set options.stdio if you want it to go elsewhere
let stdout = execSync('ls');

As well as child_process.spawnSync:

const { spawnSync} = require('child_process');
const child = spawnSync('ls', ['-lh', '/usr']);

console.log('error', child.error);
console.log('stdout ', child.stdout);
console.log('stderr ', child.stderr);

Note: The following code is still functional, but is primarily targeted at users of ES5 and before.

The module for spawning child processes with Node.js is well documented in the documentation (v5.0.0). To execute a command and fetch its complete output as a buffer, use child_process.exec:

var exec = require('child_process').exec;
var cmd = 'prince -v builds/pdf/book.html -o builds/pdf/book.pdf';

exec(cmd, function(error, stdout, stderr) {
  // command output is in stdout
});

If you need to use handle process I/O with streams, such as when you are expecting large amounts of output, use child_process.spawn:

var spawn = require('child_process').spawn;
var child = spawn('prince', [
  '-v', 'builds/pdf/book.html',
  '-o', 'builds/pdf/book.pdf'
]);

child.stdout.on('data', function(chunk) {
  // output will be here in chunks
});

// or if you want to send output elsewhere
child.stdout.pipe(dest);

If you are executing a file rather than a command, you might want to use child_process.execFile, which parameters which are almost identical to spawn, but has a fourth callback parameter like exec for retrieving output buffers. That might look a bit like this:

var execFile = require('child_process').execFile;
execFile(file, args, options, function(error, stdout, stderr) {
  // command output is in stdout
});

As of v0.11.12, Node now supports synchronous spawn and exec. All of the methods described above are asynchronous, and have a synchronous counterpart. Documentation for them can be found here. While they are useful for scripting, do note that unlike the methods used to spawn child processes asynchronously, the synchronous methods do not return an instance of ChildProcess.

Bootstrap 3 .img-responsive images are not responsive inside fieldset in FireFox

It seems to be a browser bug.

10690: Reported a bug in Firefox for responsive images (those with max-width: 100%) in table cells. No other browsers are affected. See

https://bugzilla.mozilla.org/show_bug.cgi?id=975632.

Source

.img-responsive in <fieldset> have the same behaviour.

What is an IndexOutOfRangeException / ArgumentOutOfRangeException and how do I fix it?

What Is It?

This exception means that you're trying to access a collection item by index, using an invalid index. An index is invalid when it's lower than the collection's lower bound or greater than or equal to the number of elements it contains.

When It Is Thrown

Given an array declared as:

byte[] array = new byte[4];

You can access this array from 0 to 3, values outside this range will cause IndexOutOfRangeException to be thrown. Remember this when you create and access an array.

Array Length
In C#, usually, arrays are 0-based. It means that first element has index 0 and last element has index Length - 1 (where Length is total number of items in the array) so this code doesn't work:

array[array.Length] = 0;

Moreover please note that if you have a multidimensional array then you can't use Array.Length for both dimension, you have to use Array.GetLength():

int[,] data = new int[10, 5];
for (int i=0; i < data.GetLength(0); ++i) {
    for (int j=0; j < data.GetLength(1); ++j) {
        data[i, j] = 1;
    }
}

Upper Bound Is Not Inclusive
In the following example we create a raw bidimensional array of Color. Each item represents a pixel, indices are from (0, 0) to (imageWidth - 1, imageHeight - 1).

Color[,] pixels = new Color[imageWidth, imageHeight];
for (int x = 0; x <= imageWidth; ++x) {
    for (int y = 0; y <= imageHeight; ++y) {
        pixels[x, y] = backgroundColor;
    }
}

This code will then fail because array is 0-based and last (bottom-right) pixel in the image is pixels[imageWidth - 1, imageHeight - 1]:

pixels[imageWidth, imageHeight] = Color.Black;

In another scenario you may get ArgumentOutOfRangeException for this code (for example if you're using GetPixel method on a Bitmap class).

Arrays Do Not Grow
An array is fast. Very fast in linear search compared to every other collection. It is because items are contiguous in memory so memory address can be calculated (and increment is just an addition). No need to follow a node list, simple math! You pay this with a limitation: they can't grow, if you need more elements you need to reallocate that array (this may take a relatively long time if old items must be copied to a new block). You resize them with Array.Resize<T>(), this example adds a new entry to an existing array:

Array.Resize(ref array, array.Length + 1);

Don't forget that valid indices are from 0 to Length - 1. If you simply try to assign an item at Length you'll get IndexOutOfRangeException (this behavior may confuse you if you think they may increase with a syntax similar to Insert method of other collections).

Special Arrays With Custom Lower Bound
First item in arrays has always index 0. This is not always true because you can create an array with a custom lower bound:

var array = Array.CreateInstance(typeof(byte), new int[] { 4 }, new int[] { 1 });

In that example, array indices are valid from 1 to 4. Of course, upper bound cannot be changed.

Wrong Arguments
If you access an array using unvalidated arguments (from user input or from function user) you may get this error:

private static string[] RomanNumbers =
    new string[] { "I", "II", "III", "IV", "V" };

public static string Romanize(int number)
{
    return RomanNumbers[number];
}

Unexpected Results
This exception may be thrown for another reason too: by convention, many search functions will return -1 (nullables has been introduced with .NET 2.0 and anyway it's also a well-known convention in use from many years) if they didn't find anything. Let's imagine you have an array of objects comparable with a string. You may think to write this code:

// Items comparable with a string
Console.WriteLine("First item equals to 'Debug' is '{0}'.",
    myArray[Array.IndexOf(myArray, "Debug")]);

// Arbitrary objects
Console.WriteLine("First item equals to 'Debug' is '{0}'.",
    myArray[Array.FindIndex(myArray, x => x.Type == "Debug")]);

This will fail if no items in myArray will satisfy search condition because Array.IndexOf() will return -1 and then array access will throw.

Next example is a naive example to calculate occurrences of a given set of numbers (knowing maximum number and returning an array where item at index 0 represents number 0, items at index 1 represents number 1 and so on):

static int[] CountOccurences(int maximum, IEnumerable<int> numbers) {
    int[] result = new int[maximum + 1]; // Includes 0

    foreach (int number in numbers)
        ++result[number];

    return result;
}

Of course, it's a pretty terrible implementation but what I want to show is that it'll fail for negative numbers and numbers above maximum.

How it applies to List<T>?

Same cases as array - range of valid indexes - 0 (List's indexes always start with 0) to list.Count - accessing elements outside of this range will cause the exception.

Note that List<T> throws ArgumentOutOfRangeException for the same cases where arrays use IndexOutOfRangeException.

Unlike arrays, List<T> starts empty - so trying to access items of just created list lead to this exception.

var list = new List<int>();

Common case is to populate list with indexing (similar to Dictionary<int, T>) will cause exception:

list[0] = 42; // exception
list.Add(42); // correct

IDataReader and Columns
Imagine you're trying to read data from a database with this code:

using (var connection = CreateConnection()) {
    using (var command = connection.CreateCommand()) {
        command.CommandText = "SELECT MyColumn1, MyColumn2 FROM MyTable";

        using (var reader = command.ExecuteReader()) {
            while (reader.Read()) {
                ProcessData(reader.GetString(2)); // Throws!
            }
        }
    }
}

GetString() will throw IndexOutOfRangeException because you're dataset has only two columns but you're trying to get a value from 3rd one (indices are always 0-based).

Please note that this behavior is shared with most IDataReader implementations (SqlDataReader, OleDbDataReader and so on).

You can get the same exception also if you use the IDataReader overload of the indexer operator that takes a column name and pass an invalid column name.
Suppose for example that you have retrieved a column named Column1 but then you try to retrieve the value of that field with

 var data = dr["Colum1"];  // Missing the n in Column1.

This happens because the indexer operator is implemented trying to retrieve the index of a Colum1 field that doesn't exist. The GetOrdinal method will throw this exception when its internal helper code returns a -1 as the index of "Colum1".

Others
There is another (documented) case when this exception is thrown: if, in DataView, data column name being supplied to the DataViewSort property is not valid.

How to Avoid

In this example, let me assume, for simplicity, that arrays are always monodimensional and 0-based. If you want to be strict (or you're developing a library), you may need to replace 0 with GetLowerBound(0) and .Length with GetUpperBound(0) (of course if you have parameters of type System.Array, it doesn't apply for T[]). Please note that in this case, upper bound is inclusive then this code:

for (int i=0; i < array.Length; ++i) { }

Should be rewritten like this:

for (int i=array.GetLowerBound(0); i <= array.GetUpperBound(0); ++i) { }

Please note that this is not allowed (it'll throw InvalidCastException), that's why if your parameters are T[] you're safe about custom lower bound arrays:

void foo<T>(T[] array) { }

void test() {
    // This will throw InvalidCastException, cannot convert Int32[] to Int32[*]
    foo((int)Array.CreateInstance(typeof(int), new int[] { 1 }, new int[] { 1 }));
}

Validate Parameters
If index comes from a parameter you should always validate them (throwing appropriate ArgumentException or ArgumentOutOfRangeException). In the next example, wrong parameters may cause IndexOutOfRangeException, users of this function may expect this because they're passing an array but it's not always so obvious. I'd suggest to always validate parameters for public functions:

static void SetRange<T>(T[] array, int from, int length, Func<i, T> function)
{
    if (from < 0 || from>= array.Length)
        throw new ArgumentOutOfRangeException("from");

    if (length < 0)
        throw new ArgumentOutOfRangeException("length");

    if (from + length > array.Length)
        throw new ArgumentException("...");

    for (int i=from; i < from + length; ++i)
        array[i] = function(i);
}

If function is private you may simply replace if logic with Debug.Assert():

Debug.Assert(from >= 0 && from < array.Length);

Check Object State
Array index may not come directly from a parameter. It may be part of object state. In general is always a good practice to validate object state (by itself and with function parameters, if needed). You can use Debug.Assert(), throw a proper exception (more descriptive about the problem) or handle that like in this example:

class Table {
    public int SelectedIndex { get; set; }
    public Row[] Rows { get; set; }

    public Row SelectedRow {
        get {
            if (Rows == null)
                throw new InvalidOperationException("...");

            // No or wrong selection, here we just return null for
            // this case (it may be the reason we use this property
            // instead of direct access)
            if (SelectedIndex < 0 || SelectedIndex >= Rows.Length)
                return null;

            return Rows[SelectedIndex];
        }
}

Validate Return Values
In one of previous examples we directly used Array.IndexOf() return value. If we know it may fail then it's better to handle that case:

int index = myArray[Array.IndexOf(myArray, "Debug");
if (index != -1) { } else { }

How to Debug

In my opinion, most of the questions, here on SO, about this error can be simply avoided. The time you spend to write a proper question (with a small working example and a small explanation) could easily much more than the time you'll need to debug your code. First of all, read this Eric Lippert's blog post about debugging of small programs, I won't repeat his words here but it's absolutely a must read.

You have source code, you have exception message with a stack trace. Go there, pick right line number and you'll see:

array[index] = newValue;

You found your error, check how index increases. Is it right? Check how array is allocated, is coherent with how index increases? Is it right according to your specifications? If you answer yes to all these questions, then you'll find good help here on StackOverflow but please first check for that by yourself. You'll save your own time!

A good start point is to always use assertions and to validate inputs. You may even want to use code contracts. When something went wrong and you can't figure out what happens with a quick look at your code then you have to resort to an old friend: debugger. Just run your application in debug inside Visual Studio (or your favorite IDE), you'll see exactly which line throws this exception, which array is involved and which index you're trying to use. Really, 99% of the times you'll solve it by yourself in a few minutes.

If this happens in production then you'd better to add assertions in incriminated code, probably we won't see in your code what you can't see by yourself (but you can always bet).

The VB.NET side of the story

Everything that we have said in the C# answer is valid for VB.NET with the obvious syntax differences but there is an important point to consider when you deal with VB.NET arrays.

In VB.NET, arrays are declared setting the maximum valid index value for the array. It is not the count of the elements that we want to store in the array.

' declares an array with space for 5 integer 
' 4 is the maximum valid index starting from 0 to 4
Dim myArray(4) as Integer

So this loop will fill the array with 5 integers without causing any IndexOutOfRangeException

For i As Integer = 0 To 4
    myArray(i) = i
Next

The VB.NET rule

Mutex example / tutorial?

While a mutex may be used to solve other problems, the primary reason they exist is to provide mutual exclusion and thereby solve what is known as a race condition. When two (or more) threads or processes are attempting to access the same variable concurrently, we have potential for a race condition. Consider the following code

//somewhere long ago, we have i declared as int
void my_concurrently_called_function()
{
  i++;
}

The internals of this function look so simple. It's only one statement. However, a typical pseudo-assembly language equivalent might be:

load i from memory into a register
add 1 to i
store i back into memory

Because the equivalent assembly-language instructions are all required to perform the increment operation on i, we say that incrementing i is a non-atmoic operation. An atomic operation is one that can be completed on the hardware with a gurantee of not being interrupted once the instruction execution has begun. Incrementing i consists of a chain of 3 atomic instructions. In a concurrent system where several threads are calling the function, problems arise when a thread reads or writes at the wrong time. Imagine we have two threads running simultaneoulsy and one calls the function immediately after the other. Let's also say that we have i initialized to 0. Also assume that we have plenty of registers and that the two threads are using completely different registers, so there will be no collisions. The actual timing of these events may be:

thread 1 load 0 into register from memory corresponding to i //register is currently 0
thread 1 add 1 to a register //register is now 1, but not memory is 0
thread 2 load 0 into register from memory corresponding to i
thread 2 add 1 to a register //register is now 1, but not memory is 0
thread 1 write register to memory //memory is now 1
thread 2 write register to memory //memory is now 1

What's happened is that we have two threads incrementing i concurrently, our function gets called twice, but the outcome is inconsistent with that fact. It looks like the function was only called once. This is because the atomicity is "broken" at the machine level, meaning threads can interrupt each other or work together at the wrong times.

We need a mechanism to solve this. We need to impose some ordering to the instructions above. One common mechanism is to block all threads except one. Pthread mutex uses this mechanism.

Any thread which has to execute some lines of code which may unsafely modify shared values by other threads at the same time (using the phone to talk to his wife), should first be made acquire a lock on a mutex. In this way, any thread that requires access to the shared data must pass through the mutex lock. Only then will a thread be able to execute the code. This section of code is called a critical section.

Once the thread has executed the critical section, it should release the lock on the mutex so that another thread can acquire a lock on the mutex.

The concept of having a mutex seems a bit odd when considering humans seeking exclusive access to real, physical objects but when programming, we must be intentional. Concurrent threads and processes don't have the social and cultural upbringing that we do, so we must force them to share data nicely.

So technically speaking, how does a mutex work? Doesn't it suffer from the same race conditions that we mentioned earlier? Isn't pthread_mutex_lock() a bit more complex that a simple increment of a variable?

Technically speaking, we need some hardware support to help us out. The hardware designers give us machine instructions that do more than one thing but are guranteed to be atomic. A classic example of such an instruction is the test-and-set (TAS). When trying to acquire a lock on a resource, we might use the TAS might check to see if a value in memory is 0. If it is, that would be our signal that the resource is in use and we do nothing (or more accurately, we wait by some mechanism. A pthreads mutex will put us into a special queue in the operating system and will notify us when the resource becomes available. Dumber systems may require us to do a tight spin loop, testing the condition over and over). If the value in memory is not 0, the TAS sets the location to something other than 0 without using any other instructions. It's like combining two assembly instructions into 1 to give us atomicity. Thus, testing and changing the value (if changing is appropriate) cannot be interrupted once it has begun. We can build mutexes on top of such an instruction.

Note: some sections may appear similar to an earlier answer. I accepted his invite to edit, he preferred the original way it was, so I'm keeping what I had which is infused with a little bit of his verbiage.

iPhone - Get Position of UIView within entire UIWindow

In Swift:

let globalPoint = aView.superview?.convertPoint(aView.frame.origin, toView: nil)

What is the dual table in Oracle?

It's a object to put in the from that return 1 empty row. For example: select 1 from dual; returns 1

select 21+44 from dual; returns 65

select [sequence].nextval from dual; returns the next value from the sequence.

Can I set the cookies to be used by a WKWebView?

The cookies must be set on the configuration before the WKWebView is created. Otherwise, even with WKHTTPCookieStore's setCookie completion handler, the cookies won't reliably be synced to the web view. This goes back to this line from the docs on WKWebViewConfiguration

@NSCopying var configuration: WKWebViewConfiguration { get }

That @NSCopying is somewhat of a deep copy. The implementation is beyond me, but the end result is that unless you set cookies before initializing the webview, you can't count on the cookies being there. This can complicate app architecture because initializing a view becomes an asynchronous process. You'll end up with something like this

extension WKWebViewConfiguration {
    /// Async Factory method to acquire WKWebViewConfigurations packaged with system cookies
    static func cookiesIncluded(completion: @escaping (WKWebViewConfiguration?) -> Void) {
        let config = WKWebViewConfiguration()
        guard let cookies = HTTPCookieStorage.shared.cookies else {
            completion(config)
            return
        }
        // Use nonPersistent() or default() depending on if you want cookies persisted to disk
        // and shared between WKWebViews of the same app (default), or not persisted and not shared
        // across WKWebViews in the same app.
        let dataStore = WKWebsiteDataStore.nonPersistent()
        let waitGroup = DispatchGroup()
        for cookie in cookies {
            waitGroup.enter()
            dataStore.httpCookieStore.setCookie(cookie) { waitGroup.leave() }
        }
        waitGroup.notify(queue: DispatchQueue.main) {
            config.websiteDataStore = dataStore
            completion(config)
        }
    }
}

and then to use it something like

override func loadView() {
    view = UIView()
    WKWebViewConfiguration.cookiesIncluded { [weak self] config in
        let webView = WKWebView(frame: .zero, configuration: webConfiguration)
        webView.load(request)
        self.view = webView
    }
}

The above example defers view creation until the last possible moment, another solution would be to create the config or webview well in advance and handle the asynchronous nature before creation of a view controller.

A final note: once you create this webview, you have set it loose into the wild, you can't add more cookies without using methods described in this answer. You can however use the WKHTTPCookieStoreObserver api to at least observe changes happening to cookies. So if a session cookie gets updated in the webview, you can manually update the system's HTTPCookieStorage with this new cookie if desired.

For more on this, skip to 18:00 at this 2017 WWDC Session Custom Web Content Loading. At the beginning of this session, there is a deceptive code sample which omits the fact that the webview should be created in the completion handler.

cookieStore.setCookie(cookie!) {
    webView.load(loggedInURLRequest)
}

The live demo at 18:00 clarifies this.

Edit As of Mojave Beta 7 and iOS 12 Beta 7 at least, I'm seeing much more consistent behavior with cookies. The setCookie(_:) method even appears to allow setting cookies after the WKWebView has been created. I did find it important though, to not touch the processPool variable at all. The cookie setting functionality works best when no additional pools are created and when that property is left well alone. I think it's safe to say we were having issues due to some bugs in WebKit.

Android Starting Service at Boot Time , How to restart service class after device Reboot?

Also register your created service in the Manifest and uses-permission as

<application ...>
   <service android:name=".MyBroadcastReceiver">
        <intent-filter>
            <action android:name="com.example.MyBroadcastReciver"/>
        </intent-filter>
   </service>
</application>
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>

and then in braod cast Reciever call your service

public class MyBroadcastReceiver extends BroadcastReceiver 
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        Intent myIntent = new Intent(context, MyService.class);
        context.startService(myIntent);
    }
}

Makefile ifeq logical or

As found on the mailing list archive,

one can use the filter function.

For example

ifeq ($(GCC_MINOR),$(filter $(GCC_MINOR),4 5))

filter X, A B will return those of A,B that are equal to X. Note, while this is not relevant in the above example, this is a XOR operation. I.e. if you instead have something like:

ifeq (4, $(filter 4, $(VAR1) $(VAR2)))

And then do e.g. make VAR1=4 VAR2=4, the filter will return 4 4, which is not equal to 4.

A variation that performs an OR operation instead is:

ifneq (,$(filter $(GCC_MINOR),4 5))

where a negative comparison against an empty string is used instead (filter will return en empty string if GCC_MINOR doesn't match the arguments). Using the VAR1/VAR2 example it would look like this:

ifneq (, $(filter 4, $(VAR1) $(VAR2)))

The downside to those methods is that you have to be sure that these arguments will always be single words. For example, if VAR1 is 4 foo, the filter result is still 4, and the ifneq expression is still true. If VAR1 is 4 5, the filter result is 4 5 and the ifneq expression is true.

One easy alternative is to just put the same operation in both the ifeq and else ifeq branch, e.g. like this:

ifeq ($(GCC_MINOR),4)
    @echo Supported version
else ifeq ($(GCC_MINOR),5)
    @echo Supported version
else
    @echo Unsupported version
endif

Activate tabpage of TabControl

For Windows Smart device (compact frame work ) (MC75-Motorola devices)

     mytabControl.SelectedIndex = 1

Boxplot in R showing the mean

With ggplot2:

p<-qplot(spray,count,data=InsectSprays,geom='boxplot')
p<-p+stat_summary(fun.y=mean,shape=1,col='red',geom='point')
print(p)

How to view the list of compile errors in IntelliJ?

the "problem view" mentioned in previous answers was helpful, but i saw it didn't catch all the errors in project. After running application, it began populating other classes that had issues but didn't appear at first in that problems view.

Java - How to convert type collection into ArrayList?

The following code will fail:

List<String> will_fail =  (List<String>)Collections.unmodifiableCollection(new ArrayList<String>());

This instead will work:

List<String> will_work = new ArrayList<String>(Collections.unmodifiableCollection(new ArrayList<String>()));

Combine two (or more) PDF's

Here is a single function that will merge X amount of PDFs using PDFSharp

using PdfSharp;
using PdfSharp.Pdf;
using PdfSharp.Pdf.IO;

public static void MergePDFs(string targetPath, params string[] pdfs) {
    using(PdfDocument targetDoc = new PdfDocument()){
        foreach (string pdf in pdfs) {
            using (PdfDocument pdfDoc = PdfReader.Open(pdf, PdfDocumentOpenMode.Import)) {
                for (int i = 0; i < pdfDoc.PageCount; i++) {
                    targetDoc.AddPage(pdfDoc.Pages[i]);
                }
            }
        }
        targetDoc.Save(targetPath);
    }
}

How to change the data type of a column without dropping the column with query?

it's simple! just type bellow query

alter table table_Name alter column column_name datatype

alter table Message alter column message nvarchar(1024);

it will work happy programming

The endpoint reference (EPR) for the Operation not found is

It happens because the source WSDL in each operation has not defined the SOAPAction value.

e.g.

<soap12:operation soapAction="" style="document"/>

His is important for axis server.

If you have created the service on netbeans or another, don't forget to set the value action on the tag @WebMethod

e.g. @WebMethod(action = "hello", operationName = "hello")

This will create the SOAPAction value by itself.

Auto Scale TextView Text to Fit within Bounds

I started with Chase's AutoResizeTextView class, and made a minor change so it would fit both vertically and horizontally.

I also discovered a bug which causes a Null Pointer Exception in the Layout Editor (in Eclipse) under some rather obscure conditions.

Change 1: Fit the text both vertically and horizontally

Chase's original version reduces the text size until it fits vertically, but allows the text to be wider than the target. In my case, I needed the text to fit a specified width.

This change makes it resize until the text fits both vertically and horizontally.

In resizeText(int,int) change from:

// Get the required text height
int textHeight = getTextHeight(text, textPaint, width, targetTextSize);

// Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes
while(textHeight > height && targetTextSize > mMinTextSize) {
    targetTextSize = Math.max(targetTextSize - 2, mMinTextSize);
    textHeight = getTextHeight(text, textPaint, width, targetTextSize);
    }

to:

// Get the required text height
int textHeight = getTextHeight(text, textPaint, width, targetTextSize);
int textWidth  = getTextWidth(text, textPaint, width, targetTextSize);

// Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes
while(((textHeight >= height) || (textWidth >= width) ) && targetTextSize > mMinTextSize) {
    targetTextSize = Math.max(targetTextSize - 2, mMinTextSize);
    textHeight = getTextHeight(text, textPaint, width, targetTextSize);
    textWidth  = getTextWidth(text, textPaint, width, targetTextSize);
    }

Then, at the end of the file, append the getTextWidth() routine; it's just a slightly modified getTextHeight(). It probably would be more efficient to combine them to one routine which returns both height and width.

// Set the text size of the text paint object and use a static layout to render text off screen before measuring
private int getTextWidth(CharSequence source, TextPaint paint, int width, float textSize) {
    // Update the text paint object
    paint.setTextSize(textSize);
    // Draw using a static layout
    StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
    layout.draw(sTextResizeCanvas);
    return layout.getWidth();
}

Change 2: Fix a EmptyStackException in the Eclipse Android Layout Editor

Under rather obscure and very precise conditions, the Layout Editor will fail to display the graphical display of the layout; it will throw an "EmptyStackException: null" exception in com.android.ide.eclipse.adt.

The conditions required are:
- create an AutoResizeTextView widget
- create a style for that widget
- specify the text item in the style; not in the widget definition

as in:

res/layout/main.xml:

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

    <com.ajw.DemoCrashInADT.AutoResizeTextView
        android:id="@+id/resizingText"
        style="@style/myTextStyle" />

</LinearLayout>

res/values/myStyles.xml:

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

    <style name="myTextStyle" parent="@android:style/Widget.TextView">
        <item name="android:layout_height">wrap_content</item>
        <item name="android:layout_width">fill_parent</item>
        <item name="android:text">some message</item>
    </style>

</resources>

With these files, selecting the Graphical Layout tab when editing main.xml will display:

error!
EmptyStackException: null
Exception details are logged in Window > Show View > Error Log

instead of the graphical view of the layout.

To keep an already too-long story shorter, I tracked this down to the following lines (again in resizeText):

// If there is a max text size set, use the lesser of that and the default text size
float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize) : mTextSize;

The problem is that under the specific conditions, mTextSize is never initialized; it has the value 0.

With the above, targetTextSize is set to zero (as a result of Math.min).

That zero is passed to getTextHeight() (and getTextWidth()) as the textSize argument. When it gets to
layout.draw(sTextResizeCanvas);
we get the exception.

It's more efficient to test if (mTextSize == 0) at the beginning of resizeText() rather than testing in getTextHeight() and getTextWidth(); testing earlier saves all the intervening work.

With these updates, the file (as in my crash-demo test app) is now:

//
// from:  http://stackoverflow.com/questions/5033012/auto-scale-textview-text-to-fit-within-bounds
//
//

package com.ajw.DemoCrashInADT;

import android.content.Context;
import android.graphics.Canvas;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.widget.TextView;

/**
 * Text view that auto adjusts text size to fit within the view. If the text
 * size equals the minimum text size and still does not fit, append with an
 * ellipsis.
 *
 * 2011-10-29 changes by Alan Jay Weiner
 *              * change to fit both vertically and horizontally  
 *              * test mTextSize for 0 in resizeText() to fix exception in Layout Editor
 *
 * @author Chase Colburn
 * @since Apr 4, 2011
 */
public class AutoResizeTextView extends TextView {

    // Minimum text size for this text view
    public static final float MIN_TEXT_SIZE = 20;

    // Interface for resize notifications
    public interface OnTextResizeListener {
        public void onTextResize(TextView textView, float oldSize, float newSize);
    }

    // Off screen canvas for text size rendering
    private static final Canvas sTextResizeCanvas = new Canvas();

    // Our ellipse string
    private static final String mEllipsis = "...";

    // Registered resize listener
    private OnTextResizeListener mTextResizeListener;

    // Flag for text and/or size changes to force a resize
    private boolean mNeedsResize = false;

    // Text size that is set from code. This acts as a starting point for
    // resizing
    private float mTextSize;

    // Temporary upper bounds on the starting text size
    private float mMaxTextSize = 0;

    // Lower bounds for text size
    private float mMinTextSize = MIN_TEXT_SIZE;

    // Text view line spacing multiplier
    private float mSpacingMult = 1.0f;

    // Text view additional line spacing
    private float mSpacingAdd = 0.0f;

    // Add ellipsis to text that overflows at the smallest text size
    private boolean mAddEllipsis = true;


    // Default constructor override
    public AutoResizeTextView(Context context) {
        this(context, null);
    }


    // Default constructor when inflating from XML file
    public AutoResizeTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }


    // Default constructor override
    public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mTextSize = getTextSize();
    }


    /**
     * When text changes, set the force resize flag to true and reset the text
     * size.
     */
    @Override
    protected void onTextChanged(final CharSequence text, final int start,
            final int before, final int after) {
        mNeedsResize = true;
        // Since this view may be reused, it is good to reset the text size
        resetTextSize();
    }


    /**
     * If the text view size changed, set the force resize flag to true
     */
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        if (w != oldw || h != oldh) {
            mNeedsResize = true;
        }
    }


    /**
     * Register listener to receive resize notifications
     *
     * @param listener
     */
    public void setOnResizeListener(OnTextResizeListener listener) {
        mTextResizeListener = listener;
    }


    /**
     * Override the set text size to update our internal reference values
     */
    @Override
    public void setTextSize(float size) {
        super.setTextSize(size);
        mTextSize = getTextSize();
    }


    /**
     * Override the set text size to update our internal reference values
     */
    @Override
    public void setTextSize(int unit, float size) {
        super.setTextSize(unit, size);
        mTextSize = getTextSize();
    }


    /**
     * Override the set line spacing to update our internal reference values
     */
    @Override
    public void setLineSpacing(float add, float mult) {
        super.setLineSpacing(add, mult);
        mSpacingMult = mult;
        mSpacingAdd = add;
    }


    /**
     * Set the upper text size limit and invalidate the view
     *
     * @param maxTextSize
     */
    public void setMaxTextSize(float maxTextSize) {
        mMaxTextSize = maxTextSize;
        requestLayout();
        invalidate();
    }


    /**
     * Return upper text size limit
     *
     * @return
     */
    public float getMaxTextSize() {
        return mMaxTextSize;
    }


    /**
     * Set the lower text size limit and invalidate the view
     *
     * @param minTextSize
     */
    public void setMinTextSize(float minTextSize) {
        mMinTextSize = minTextSize;
        requestLayout();
        invalidate();
    }


    /**
     * Return lower text size limit
     *
     * @return
     */
    public float getMinTextSize() {
        return mMinTextSize;
    }


    /**
     * Set flag to add ellipsis to text that overflows at the smallest text size
     *
     * @param addEllipsis
     */
    public void setAddEllipsis(boolean addEllipsis) {
        mAddEllipsis = addEllipsis;
    }


    /**
     * Return flag to add ellipsis to text that overflows at the smallest text
     * size
     *
     * @return
     */
    public boolean getAddEllipsis() {
        return mAddEllipsis;
    }


    /**
     * Reset the text to the original size
     */
    public void resetTextSize() {
        super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
        mMaxTextSize = mTextSize;
    }


    /**
     * Resize text after measuring
     */
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        if (changed || mNeedsResize) {
            int widthLimit = (right - left) - getCompoundPaddingLeft()
                    - getCompoundPaddingRight();
            int heightLimit = (bottom - top) - getCompoundPaddingBottom()
                    - getCompoundPaddingTop();
            resizeText(widthLimit, heightLimit);
        }
        super.onLayout(changed, left, top, right, bottom);
    }


    /**
     * Resize the text size with default width and height
     */
    public void resizeText() {
        int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop();
        int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight();
        resizeText(widthLimit, heightLimit);
    }


    /**
     * Resize the text size with specified width and height
     *
     * @param width
     * @param height
     */
    public void resizeText(int width, int height) {
        CharSequence text = getText();
        // Do not resize if the view does not have dimensions or there is no
        // text
        // or if mTextSize has not been initialized
        if (text == null || text.length() == 0 || height <= 0 || width <= 0
                || mTextSize == 0) {
            return;
        }

        // Get the text view's paint object
        TextPaint textPaint = getPaint();

        // Store the current text size
        float oldTextSize = textPaint.getTextSize();

        // If there is a max text size set, use the lesser of that and the
        // default text size
        float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize)
                : mTextSize;

        // Get the required text height
        int textHeight = getTextHeight(text, textPaint, width, targetTextSize);
        int textWidth = getTextWidth(text, textPaint, width, targetTextSize);

        // Until we either fit within our text view or we had reached our min
        // text size, incrementally try smaller sizes
        while (((textHeight > height) || (textWidth > width))
                && targetTextSize > mMinTextSize) {
            targetTextSize = Math.max(targetTextSize - 2, mMinTextSize);
            textHeight = getTextHeight(text, textPaint, width, targetTextSize);
            textWidth = getTextWidth(text, textPaint, width, targetTextSize);
        }

        // If we had reached our minimum text size and still don't fit, append
        // an ellipsis
        if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) {
            // Draw using a static layout
            StaticLayout layout = new StaticLayout(text, textPaint, width,
                    Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false);
            layout.draw(sTextResizeCanvas);
            int lastLine = layout.getLineForVertical(height) - 1;
            int start = layout.getLineStart(lastLine);
            int end = layout.getLineEnd(lastLine);
            float lineWidth = layout.getLineWidth(lastLine);
            float ellipseWidth = textPaint.measureText(mEllipsis);

            // Trim characters off until we have enough room to draw the
            // ellipsis
            while (width < lineWidth + ellipseWidth) {
                lineWidth = textPaint.measureText(text.subSequence(start, --end + 1)
                        .toString());
            }
            setText(text.subSequence(0, end) + mEllipsis);

        }

        // Some devices try to auto adjust line spacing, so force default line
        // spacing
        // and invalidate the layout as a side effect
        textPaint.setTextSize(targetTextSize);
        setLineSpacing(mSpacingAdd, mSpacingMult);

        // Notify the listener if registered
        if (mTextResizeListener != null) {
            mTextResizeListener.onTextResize(this, oldTextSize, targetTextSize);
        }

        // Reset force resize flag
        mNeedsResize = false;
    }


    // Set the text size of the text paint object and use a static layout to
    // render text off screen before measuring
    private int getTextHeight(CharSequence source, TextPaint paint, int width,
            float textSize) {
        // Update the text paint object
        paint.setTextSize(textSize);
        // Draw using a static layout
        StaticLayout layout = new StaticLayout(source, paint, width,
                Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
        layout.draw(sTextResizeCanvas);
        return layout.getHeight();
    }


    // Set the text size of the text paint object and use a static layout to
    // render text off screen before measuring
    private int getTextWidth(CharSequence source, TextPaint paint, int width,
            float textSize) {
        // Update the text paint object
        paint.setTextSize(textSize);
        // Draw using a static layout
        StaticLayout layout = new StaticLayout(source, paint, width,
                Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
        layout.draw(sTextResizeCanvas);
        return layout.getWidth();
    }

}

A big thank you to Chase for posting the initial code. I enjoyed reading through it to see how it worked, and I'm pleased to be able to add to it.

DIV height set as percentage of screen?

make position absolute for that div.

http://jsfiddle.net/btevfik/KkKeZ/

How to fix error ::Format of the initialization string does not conform to specification starting at index 0::

An unwanted single quote was my problem. Checking the connection string from the location of the index mentioned in the error string helped me spot the issue.

Align inline-block DIVs to top of container element

Add overflow: auto to the container div. http://www.quirksmode.org/css/clearing.html This website shows a few options when having this issue.

How to stop "setInterval"

You have to store the timer id of the interval when you start it, you will use this value later to stop it, using the clearInterval function:

$(function () {
  var timerId = 0;

  $('textarea').focus(function () {
    timerId = setInterval(function () {
      // interval function body
    }, 1000);
  });

  $('textarea').blur(function () {
    clearInterval(timerId);
  });

});

MySQL 1062 - Duplicate entry '0' for key 'PRIMARY'

You need to specify the primary key as auto-increment

CREATE TABLE `momento_distribution`
  (
     `momento_id`       INT(11) NOT NULL AUTO_INCREMENT,
     `momento_idmember` INT(11) NOT NULL,
     `created_at`       DATETIME DEFAULT NULL,
     `updated_at`       DATETIME DEFAULT NULL,
     `unread`           TINYINT(1) DEFAULT '1',
     `accepted`         VARCHAR(10) NOT NULL DEFAULT 'pending',
     `ext_member`       VARCHAR(255) DEFAULT NULL,
     PRIMARY KEY (`momento_id`, `momento_idmember`),
     KEY `momento_distribution_FI_2` (`momento_idmember`),
     KEY `accepted` (`accepted`, `ext_member`)
  )
ENGINE=InnoDB
DEFAULT CHARSET=latin1$$

With regards to comment below, how about:

ALTER TABLE `momento_distribution`
  CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT,
  DROP PRIMARY KEY,
  ADD PRIMARY KEY (`id`);

A PRIMARY KEY is a unique index, so if it contains duplicates, you cannot assign the column to be unique index, so you may need to create a new column altogether

Why is a "GRANT USAGE" created the first time I grant a user privileges?

I was trying to find the meaning of GRANT USAGE on *.* TO and found here. I can clarify that GRANT USAGE on *.* TO user IDENTIFIED BY PASSWORD password will be granted when you create the user with the following command (CREATE):

CREATE USER 'user'@'localhost' IDENTIFIED BY 'password';

When you grant privilege with GRANT, new privilege s will be added on top of it.

How do implement a breadth first traversal?

Breadth first search

Queue<TreeNode> queue = new LinkedList<BinaryTree.TreeNode>() ;
public void breadth(TreeNode root) {
    if (root == null)
        return;
    queue.clear();
    queue.add(root);
    while(!queue.isEmpty()){
        TreeNode node = queue.remove();
        System.out.print(node.element + " ");
        if(node.left != null) queue.add(node.left);
        if(node.right != null) queue.add(node.right);
    }

}

PHP Multidimensional Array Searching (Find key by specific value)

function search($array, $key, $value) 
{ 
    $results = array(); 

    if (is_array($array)) 
    { 
        if (isset($array[$key]) && $array[$key] == $value) 
            $results[] = $array; 

        foreach ($array as $subarray) 
            $results = array_merge($results, search($subarray, $key, $value)); 
    } 

    return $results; 
}

PHP get and set magic methods

I'd recommend to use an array for storing all values via __set().

class foo {

    protected $values = array();

    public function __get( $key )
    {
        return $this->values[ $key ];
    }

    public function __set( $key, $value )
    {
        $this->values[ $key ] = $value;
    }

}

This way you make sure, that you can't access the variables in another way (note that $values is protected), to avoid collisions.

Package name does not correspond to the file path - IntelliJ

Kotlin

For those using Kotlin who are following the docs package conventions:

In pure Kotlin projects, the recommended directory structure is to follow the package structure with the common root package omitted (e.g. if all the code in the project is in the "org.example.kotlin" package and its subpackages, files with the "org.example.kotlin" package should be placed directly under the source root, and files in "org.example.kotlin.foo.bar" should be in the "foo/bar" subdirectory of the source root).

IntelliJ doesn't support this yet. The only thing you can do is to disable this warning, and accept that the IDE will not help you with refactorings when it comes to changing folders/files structures.

Using Jasmine to spy on a function without an object

There is 2 alternative which I use (for jasmine 2)

This one is not quite explicit because it seems that the function is actually a fake.

test = createSpy().and.callFake(test);

The second more verbose, more explicit, and "cleaner":

test = createSpy('testSpy', test).and.callThrough();

-> jasmine source code to see the second argument

How can I set size of a button?

The following bit of code does what you ask for. Just make sure that you assign enough space so that the text on the button becomes visible

JFrame frame = new JFrame("test");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new GridLayout(4,4,4,4));

for(int i=0 ; i<16 ; i++){
    JButton btn = new JButton(String.valueOf(i));
    btn.setPreferredSize(new Dimension(40, 40));
    panel.add(btn);
}
frame.setContentPane(panel);
frame.pack();
frame.setVisible(true);

The X and Y (two first parameters of the GridLayout constructor) specify the number of rows and columns in the grid (respectively). You may leave one of them as 0 if you want that value to be unbounded.

Edit

I've modified the provided code and I believe it now conforms to what is desired:

JFrame frame = new JFrame("Colored Trails");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));

JPanel firstPanel = new JPanel();
firstPanel.setLayout(new GridLayout(4, 4));
firstPanel.setMaximumSize(new Dimension(400, 400));
JButton btn;
for (int i=1; i<=4; i++) {
    for (int j=1; j<=4; j++) {
        btn = new JButton();
        btn.setPreferredSize(new Dimension(100, 100));
        firstPanel.add(btn);
    }
}

JPanel secondPanel = new JPanel();
secondPanel.setLayout(new GridLayout(5, 13));
secondPanel.setMaximumSize(new Dimension(520, 200));
for (int i=1; i<=5; i++) {
    for (int j=1; j<=13; j++) {
        btn = new JButton();
        btn.setPreferredSize(new Dimension(40, 40));
        secondPanel.add(btn);
    }
}

mainPanel.add(firstPanel);
mainPanel.add(secondPanel);
frame.setContentPane(mainPanel);

frame.setSize(520,600);
frame.setMinimumSize(new Dimension(520,600));
frame.setVisible(true);

Basically I now set the preferred size of the panels and a minimum size for the frame.

Apply function to pandas groupby

I saw a nested function technique for computing a weighted average on S.O. one time, altering that technique can solve your issue.

def group_weight(overall_size):
    def inner(group):
        return len(group)/float(overall_size)
    inner.__name__ = 'weight'
    return inner

d = {"my_label": pd.Series(['A','B','A','C','D','D','E'])}
df = pd.DataFrame(d)
print df.groupby('my_label').apply(group_weight(len(df)))



my_label
A    0.285714
B    0.142857
C    0.142857
D    0.285714
E    0.142857
dtype: float64

Here is how to do a weighted average within groups

def wavg(val_col_name,wt_col_name):
    def inner(group):
        return (group[val_col_name] * group[wt_col_name]).sum() / group[wt_col_name].sum()
    inner.__name__ = 'wgt_avg'
    return inner



d = {"P": pd.Series(['A','B','A','C','D','D','E'])
     ,"Q": pd.Series([1,2,3,4,5,6,7])
    ,"R": pd.Series([0.1,0.2,0.3,0.4,0.5,0.6,0.7])
     }

df = pd.DataFrame(d)
print df.groupby('P').apply(wavg('Q','R'))

P
A    2.500000
B    2.000000
C    4.000000
D    5.545455
E    7.000000
dtype: float64

Setting up and using environment variables in IntelliJ Idea

In addition to the above answer and restarting the IDE didn't do, try restarting "Jetbrains Toolbox" if you use it, this did it for me

curl Failed to connect to localhost port 80

If anyone else comes across this and the accepted answer doesn't work (it didn't for me), check to see if you need to specify a port other than 80. In my case, I was running a rails server at localhost:3000 and was just using curl http://localhost, which was hitting port 80.

Changing the command to curl http://localhost:3000 is what worked in my case.

Module not found: Error: Can't resolve 'core-js/es6'

The imports have changed for core-js version 3.0.1 - for example

import 'core-js/es6/array'; and import 'core-js/es7/array';

can now be provided simply by the following

import 'core-js/es/array';

if you would prefer not to bring in the whole of core-js

SyntaxError: multiple statements found while compiling a single statement

A (partial) practical work-around is to put things into a throw-away function.

Pasting

x = 1
x += 1
print(x)

results in

>>> x = 1
x += 1
print(x)
  File "<stdin>", line 1
    x += 1
print(x)

    ^
SyntaxError: multiple statements found while compiling a single statement
>>>

However, pasting

def abc():
  x = 1
  x += 1
  print(x)

works:

>>> def abc():
  x = 1
  x += 1
  print(x)
>>> abc()
2
>>>

Of course, this is OK for a quick one-off, won't work for everything you might want to do, etc. But then, going to ipython / jupyter qtconsole is probably the next simplest option.

Toggle display:none style with JavaScript

Give your ul an id,

<ul id='yourUlId' class="subforums" style="display: none; overflow-x: visible; overflow-y: visible; ">

then do

var yourUl = document.getElementById("yourUlId");
yourUl.style.display = yourUl.style.display === 'none' ? '' : 'none';

IF you're using jQuery, this becomes:

var $yourUl = $("#yourUlId"); 
$yourUl.css("display", $yourUl.css("display") === 'none' ? '' : 'none');

Finally, you specifically said that you wanted to manipulate this css property, and not simply show or hide the underlying element. Nonetheless I'll mention that with jQuery

$("#yourUlId").toggle();

will alternate between showing or hiding this element.

Adding a leading zero to some values in column in MySQL

Possibly:

select lpad(column, 8, 0) from table;

Edited in response to question from mylesg, in comments below:

ok, seems to make the change on the query- but how do I make it stick (change it) permanently in the table? I tried an UPDATE instead of SELECT

I'm assuming that you used a query similar to:

UPDATE table SET columnName=lpad(nums,8,0);

If that was successful, but the table's values are still without leading-zeroes, then I'd suggest you probably set the column as a numeric type? If that's the case then you'd need to alter the table so that the column is of a text/varchar() type in order to preserve the leading zeroes:

First:

ALTER TABLE `table` CHANGE `numberColumn` `numberColumn` CHAR(8);

Second, run the update:

UPDATE table SET `numberColumn`=LPAD(`numberColum`, 8, '0');

This should, then, preserve the leading-zeroes; the down-side is that the column is no longer strictly of a numeric type; so you may have to enforce more strict validation (depending on your use-case) to ensure that non-numerals aren't entered into that column.

References:

lpad().

Java - Convert String to valid URI object

Well I tried using

String converted = URLDecoder.decode("toconvert","UTF-8");

I hope this is what you were actually looking for?

Iteration ng-repeat only X times in AngularJs

All answers here seem to assume that items is an array. However, in AngularJS, it might as well be an object. In that case, neither filtering with limitTo nor array.slice will work. As one possible solution, you can convert your object to an array, if you don't mind losing the object keys. Here is an example of a filter to do just that:

myFilter.filter('obj2arr', function() {
    return function(obj) {
        if (typeof obj === 'object') {
            var arr = [], i = 0, key;
            for( key in obj ) {
                arr[i] = obj[key];
                i++;
            }
            return arr;
        }
        else {
            return obj;
        }

    };
});

Once it is an array, use slice or limitTo, as stated in other answers.

Android get Current UTC time

System.currentTimeMillis() does give you the number of milliseconds since January 1, 1970 00:00:00 UTC. The reason you see local times might be because you convert a Date instance to a string before using it. You can use DateFormats to convert Dates to Strings in any timezone:

DateFormat df = DateFormat.getTimeInstance();
df.setTimeZone(TimeZone.getTimeZone("gmt"));
String gmtTime = df.format(new Date());

Also see this related question.

iPhone SDK on Windows (alternative solutions)

There are two ways:

If you are patient (requires Ubuntu corral pc and Android SDK and some heavy terminal work to get it all set up). See Using the 3.0 SDK without paying for the priviledge.
If you are immoral (requires Mac OS X Leopard and virtualization, both only obtainable through great expense or pirating) - remove space from the following link. htt p://iphonewo rld. codinghut.com /2009/07/using-the-3-0-sdk-without-paying-for-the-priviledge/

I use the Ubuntu method myself.

DateDiff to output hours and minutes

Small change like this can be done

  SELECT  EmplID
        , EmplName
        , InTime
        , [TimeOut]
        , [DateVisited]
        , CASE WHEN minpart=0 
        THEN CAST(hourpart as nvarchar(200))+':00' 
        ELSE CAST((hourpart-1) as nvarchar(200))+':'+ CAST(minpart as nvarchar(200))END as 'total time'
        FROM 
        (
        SELECT   EmplID, EmplName, InTime, [TimeOut], [DateVisited],
        DATEDIFF(Hour,InTime, [TimeOut]) as hourpart, 
        DATEDIFF(minute,InTime, [TimeOut])%60 as minpart  
        from times) source

How do I update an entity using spring-data-jpa?

Specifically how do I tell spring-data-jpa that users that have the same username and firstname are actually EQUAL and that it is supposed to update the entity. Overriding equals did not work.

For this particular purpose one can introduce a composite key like this:

CREATE TABLE IF NOT EXISTS `test`.`user` (
  `username` VARCHAR(45) NOT NULL,
  `firstname` VARCHAR(45) NOT NULL,
  `description` VARCHAR(45) NOT NULL,
  PRIMARY KEY (`username`, `firstname`))

Mapping:

@Embeddable
public class UserKey implements Serializable {
    protected String username;
    protected String firstname;

    public UserKey() {}

    public UserKey(String username, String firstname) {
        this.username = username;
        this.firstname = firstname;
    }
    // equals, hashCode
}

Here is how to use it:

@Entity
public class UserEntity implements Serializable {
    @EmbeddedId
    private UserKey primaryKey;

    private String description;

    //...
}

JpaRepository would look like this:

public interface UserEntityRepository extends JpaRepository<UserEntity, UserKey>

Then, you could use the following idiom: accept DTO with user info, extract name and firstname and create UserKey, then create a UserEntity with this composite key and then invoke Spring Data save() which should sort everything out for you.

how to copy only the columns in a DataTable to another DataTable?

The DataTable.Clone() method works great when you want to create a completely new DataTable, but there might be cases where you would want to add the schema columns from one DataTable to another existing DataTable.

For example, if you've derived a new subclass from DataTable, and want to import schema information into it, you couldn't use Clone().

E.g.:

public class CoolNewTable : DataTable {
   public void FillFromReader(DbDataReader reader) {
       // We want to get the schema information (i.e. columns) from the 
       // DbDataReader and 
       // import it into *this* DataTable, NOT a new one.
       DataTable schema = reader.GetSchemaTable(); 
       //GetSchemaTable() returns a DataTable with the columns we want.

       ImportSchema(this, schema); // <--- how do we do this?
   }
}

The answer is just to create new DataColumns in the existing DataTable using the schema table's columns as templates.

I.e. the code for ImportSchema would be something like this:

void ImportSchema(DataTable dest, DataTable source) {
    foreach(var c in source.Columns)
        dest.Columns.Add(c);
}

or, if you're using Linq:

void ImportSchema(DataTable dest, DataTable source) {
    var cols = source.Columns.Cast<DataColumn>().ToArray();
    dest.Columns.AddRange(cols);
}

This was just one example of a situation where you might want to copy schema/columns from one DataTable into another one without using Clone() to create a completely new DataTable. I'm sure I've come across several others as well.

R Not in subset

The expression df1$id %in% idNums1 produces a logical vector. To negate it, you need to negate the whole vector:

!(df1$id %in% idNums1)

Remove an array element and shift the remaining ones

Programming Hub randomly provided a code snippet which in fact does reduce the length of an array

for (i = position_to_remove; i < length_of_array; ++i) {
        inputarray[i] = inputarray[i + 1];
}

Not sure if it's behaviour that was added only later. It does the trick though.

Performing a Stress Test on Web Application?

Trying all mentioned here, I found curl-loader as best for my purposes. very easy interface, real-time monitoring, useful statistics, from which I build graphs of performance. All features of libcurl are included.

Bootstrap tab activation with JQuery

why not select active tab first then active the selected tab content ?
1. Add class 'active' to the < li > element of tab first .
2. then use set 'active' class to selected div.

    $(document).ready( function(){
        SelectTab(1); //or use other method  to set active class to tab
        ShowInitialTabContent();

    });
    function SelectTab(tabindex)
    {
        $('.nav-tabs li ').removeClass('active');
        $('.nav-tabs li').eq(tabindex).addClass('active'); 
        //tabindex start at 0 
    }
    function FindActiveDiv()
    {  
        var DivName = $('.nav-tabs .active a').attr('href');  
        return DivName;
    }
    function RemoveFocusNonActive()
    {
        $('.nav-tabs  a').not('.active').blur();  
        //to >  remove  :hover :focus;
    }
    function ShowInitialTabContent()
    {
        RemoveFocusNonActive();
        var DivName = FindActiveDiv();
        if (DivName)
        {
            $(DivName).addClass('active'); 
        } 
    }

Spark difference between reduceByKey vs groupByKey vs aggregateByKey vs combineByKey

groupByKey() is just to group your dataset based on a key. It will result in data shuffling when RDD is not already partitioned.
reduceByKey() is something like grouping + aggregation. We can say reduceBykey() equvelent to dataset.group(...).reduce(...). It will shuffle less data unlike groupByKey().
aggregateByKey() is logically same as reduceByKey() but it lets you return result in different type. In another words, it lets you have a input as type x and aggregate result as type y. For example (1,2),(1,4) as input and (1,"six") as output. It also takes zero-value that will be applied at the beginning of each key.

Note : One similarity is they all are wide operations.

How do I implement IEnumerable<T>

Note that the IEnumerable<T> allready implemented by the System.Collections so another approach is to derive your MyObjects class from System.Collections as a base class (documentation):

System.Collections: Provides the base class for a generic collection.

We can later make our own implemenation to override the virtual System.Collections methods to provide custom behavior (only for ClearItems, InsertItem, RemoveItem, and SetItem along with Equals, GetHashCode, and ToString from Object). Unlike the List<T> which is not designed to be easily extensible.

Example:

public class FooCollection : System.Collections<Foo>
{
    //...
    protected override void InsertItem(int index, Foo newItem)
    {
        base.InsertItem(index, newItem);     
        Console.Write("An item was successfully inserted to MyCollection!");
    }
}

public static void Main()
{
    FooCollection fooCollection = new FooCollection();
    fooCollection.Add(new Foo()); //OUTPUT: An item was successfully inserted to FooCollection!
}

Please note that driving from collection recommended only in case when custom collection behavior is needed, which is rarely happens. see usage.

In Python, what is the difference between ".append()" and "+= []"?

The append() method adds a single item to the existing list

some_list1 = []
some_list1.append("something")

So here the some_list1 will get modified.

Updated:

Whereas using + to combine the elements of lists (more than one element) in the existing list similar to the extend (as corrected by Flux).

some_list2 = []
some_list2 += ["something"]

So here the some_list2 and ["something"] are the two lists that are combined.

Java: recommended solution for deep cloning/copying an instance

I'd suggest to override Object.clone(), call super.clone() first and than call ref = ref.clone() on all references that you want to have deep copied. It's more or less Do it yourself approach but needs a bit less coding.

100% width table overflowing div container

update your CSS to the following: this should fix

.page {
    width: 280px;
    border:solid 1px blue;
    overflow-x: auto;
}

Specify an SSH key for git push for a given domain

An alternative approach to the one offered above by Mark Longair is to use an alias that will run any git command, on any remote, with an alternative SSH key. The idea is basically to switch your SSH identity when running the git commands.

Advantages relative to the host alias approach in the other answer:

Will work with any git commands or aliases, even if you can't specify the remote explicitly.
Easier to work with many repositories because you only need to set it up once per client machine, not once per repository on each client machine.

I use a few small scripts and a git alias admin. That way I can do, for example:

git admin push

To push to the default remote using the alternative ("admin") SSH key. Again, you could use any command (not just push) with this alias. You could even do git admin clone ... to clone a repository that you would only have access to using your "admin" key.

Step 1: Create the alternative SSH keys, optionally set a passphrase in case you're doing this on someone else's machine.

Step 2: Create a script called “ssh-as.sh” that runs stuff that uses SSH, but uses a given SSH key rather than the default:

#!/bin/bash
exec ssh ${SSH_KEYFILE+-i "$SSH_KEYFILE"} "$@"

Step 3: Create a script called “git-as.sh” that runs git commands using the given SSH key.

#!/bin/bash
SSH_KEYFILE=$1 GIT_SSH=${BASH_SOURCE%/*}/ssh-as.sh exec git "${@:2}"

Step 4: Add an alias (using something appropriate for “PATH_TO_SCRIPTS_DIR” below):

# Run git commands as the SSH identity provided by the keyfile ~/.ssh/admin
git config --global alias.admin \!"PATH_TO_SCRIPTS_DIR/git-as.sh ~/.ssh/admin"

More details at: http://noamlewis.wordpress.com/2013/01/24/git-admin-an-alias-for-running-git-commands-as-a-privileged-ssh-identity/

git pull from master into the development branch

Situation: Working in my local branch, but I love to keep-up updates in the development branch named dev.

Solution: Usually, I prefer to do :

git fetch
git rebase origin/dev

What is the T-SQL syntax to connect to another SQL Server?

If you are connecting to multiple servers you should add a 'GO' before switching servers, or your sql statements will run against the wrong server.

e.g.

:CONNECT SERVER1
Select * from Table
GO
enter code here
:CONNECT SERVER1
Select * from Table
GO

http://www.sqlmatters.com/Articles/Changing%20the%20SQL%20Server%20connection%20within%20an%20SSMS%20Query%20Windows%20using%20SQLCMD%20Mode.aspx

Invalid Host Header when ngrok tries to connect to React dev server

I'm encountering a similar issue and found two solutions that work as far as viewing the application directly in a browser

ngrok http 8080 -host-header="localhost:8080"
ngrok http --host-header=rewrite 8080

obviously replace 8080 with whatever port you're running on

this solution still raises an error when I use this in an embedded page, that pulls the bundle.js from the react app. I think since it rewrites the header to localhost, when this is embedded, it's looking to localhost, which the app is no longer running on

creating triggers for After Insert, After Update and After Delete in SQL

(Update: overlooked a fault in the matter, I have corrected)

(Update2: I wrote from memory the code screwed up, repaired it)

(Update3: check on SQLFiddle)

create table Derived_Values
  (
    BusinessUnit nvarchar(100) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)
    )

go

ALTER TABLE Derived_Values ADD CONSTRAINT PK_Derived_Values
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

create table Derived_Values_Test
  (
    BusinessUnit nvarchar(150)
    ,Questions nvarchar(100)
    ,Answer nvarchar(100)
    )

go

CREATE TRIGGER trgAfterUpdate ON  [Derived_Values]
FOR UPDATE
AS  
begin
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Updated Record -- After Update Trigger.'

    insert into 
        [Derived_Values_Test]
        --(BusinessUnit,Questions, Answer) 
    SELECT 
        @BusinessUnit + i.BusinessUnit, i.Questions, i.Answer
    FROM 
        inserted i
        inner join deleted d on i.BusinessUnit = d.BusinessUnit
end

go

CREATE TRIGGER trgAfterDelete ON  [Derived_Values]
FOR UPDATE
AS  
begin
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Deleted Record -- After Delete Trigger.'

    insert into 
        [Derived_Values_Test]
        --(BusinessUnit,Questions, Answer) 
    SELECT 
        @BusinessUnit + d.BusinessUnit, d.Questions, d.Answer
    FROM 
        deleted d
end

go

insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q11', 'A11')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q12', 'A12')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q21', 'A21')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q22', 'A22')

UPDATE Derived_Values SET Answer='Updated Answers A11' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q11');
UPDATE Derived_Values SET Answer='Updated Answers A12' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q12');
UPDATE Derived_Values SET Answer='Updated Answers A21' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q21');
UPDATE Derived_Values SET Answer='Updated Answers A22' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q22');

delete Derived_Values;

and then:

SELECT * FROM Derived_Values;
go

select * from Derived_Values_Test;


Record Count: 0;

BUSINESSUNIT    QUESTIONS   ANSWER
Updated Record -- After Update Trigger.BU1  Q11 Updated Answers A11
Deleted Record -- After Delete Trigger.BU1  Q11 A11
Updated Record -- After Update Trigger.BU1  Q12 Updated Answers A12
Deleted Record -- After Delete Trigger.BU1  Q12 A12
Updated Record -- After Update Trigger.BU2  Q21 Updated Answers A21
Deleted Record -- After Delete Trigger.BU2  Q21 A21
Updated Record -- After Update Trigger.BU2  Q22 Updated Answers A22
Deleted Record -- After Delete Trigger.BU2  Q22 A22

(Update4: If you want to sync: SQLFiddle)

create table Derived_Values
  (
    BusinessUnit nvarchar(100) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)
    )

go

ALTER TABLE Derived_Values ADD CONSTRAINT PK_Derived_Values
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

create table Derived_Values_Test
  (
    BusinessUnit nvarchar(150) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)
    )

go

ALTER TABLE Derived_Values_Test ADD CONSTRAINT PK_Derived_Values_Test
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

CREATE TRIGGER trgAfterInsert ON  [Derived_Values]
FOR INSERT
AS  
begin
    insert
        [Derived_Values_Test]
        (BusinessUnit,Questions,Answer)
    SELECT 
        i.BusinessUnit, i.Questions, i.Answer
    FROM 
        inserted i
end

go


CREATE TRIGGER trgAfterUpdate ON  [Derived_Values]
FOR UPDATE
AS  
begin
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Updated Record -- After Update Trigger.'

    update
        [Derived_Values_Test]
    set
        --BusinessUnit = i.BusinessUnit
        --,Questions = i.Questions
        Answer = i.Answer
    from
        [Derived_Values]
        inner join inserted i 
    on
        [Derived_Values].BusinessUnit = i.BusinessUnit
        and
        [Derived_Values].Questions = i.Questions
end

go

CREATE TRIGGER trgAfterDelete ON  [Derived_Values]
FOR DELETE
AS  
begin
    delete 
        [Derived_Values_Test]
    from
        [Derived_Values_Test]
        inner join deleted d 
    on
        [Derived_Values_Test].BusinessUnit = d.BusinessUnit
        and
        [Derived_Values_Test].Questions = d.Questions
end

go

insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q11', 'A11')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q12', 'A12')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q21', 'A21')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q22', 'A22')

UPDATE Derived_Values SET Answer='Updated Answers A11' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q11');
UPDATE Derived_Values SET Answer='Updated Answers A12' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q12');
UPDATE Derived_Values SET Answer='Updated Answers A21' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q21');
UPDATE Derived_Values SET Answer='Updated Answers A22' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q22');

--delete Derived_Values;

And then:

SELECT * FROM Derived_Values;
go

select * from Derived_Values_Test;


BUSINESSUNIT    QUESTIONS   ANSWER
BU1 Q11 Updated Answers A11
BU1 Q12 Updated Answers A12
BU2 Q21 Updated Answers A21
BU2 Q22 Updated Answers A22

BUSINESSUNIT    QUESTIONS   ANSWER
BU1 Q11 Updated Answers A11
BU1 Q12 Updated Answers A12
BU2 Q21 Updated Answers A21
BU2 Q22 Updated Answers A22

C pass int array pointer as parameter into a function

In your new code,

int func(int *B){
    *B[0] = 5;
}

B is a pointer to int, thus B[0] is an int, and you can't dereference an int. Just remove the *,

int func(int *B){
    B[0] = 5;
}

and it works.

In the initialisation

int B[10] = {NULL};

you are initialising anint with a void* (NULL). Since there is a valid conversion from void* to int, that works, but it is not quite kosher, because the conversion is implementation defined, and usually indicates a mistake by the programmer, hence the compiler warns about it.

int B[10] = {0};

is the proper way to 0-initialise an int[10].

How to convert a multipart file to File?

You can get the content of a MultipartFile by using the getBytes method and you can write to the file using Files.newOutputStream():

public void write(MultipartFile file, Path dir) {
    Path filepath = Paths.get(dir.toString(), file.getOriginalFilename());

    try (OutputStream os = Files.newOutputStream(filepath)) {
        os.write(file.getBytes());
    }
}

You can also use the transferTo method:

public void multipartFileToFile(
    MultipartFile multipart, 
    Path dir
) throws IOException {
    Path filepath = Paths.get(dir.toString(), multipart.getOriginalFilename());
    multipart.transferTo(filepath);
}

jQuery set checkbox checked

I encountered this problem too.

and here is my old doesn't work code

if(data.access == 'private'){
     Jbookaccess.removeProp("checked") ; 
    //I also have tried : Jbookaccess.removeAttr("checked") ;
 }else{
    Jbookaccess.prop("checked", true)
}

here is my new code which is worked now:

if(data.access == 'private'){
     Jbookaccess.prop("checked",false) ;
 }else{
    Jbookaccess.prop("checked", true)
}

so,the key point is before it worked ,make sure the checked property does exist and does not been removed.

cell format round and display 2 decimal places

Another way is to use FIXED function, you can specify the number of decimal places but it defaults to 2 if the places aren't specified, i.e.

=FIXED(E5,2)

or just

=FIXED(E5)

How do I import a pre-existing Java project into Eclipse and get up and running?

I think you'll have to import the project via the file->import wizard:

http://www.coderanch.com/t/419556/vc/Open-existing-project-Eclipse

It's not the last step, but it will start you on your way.

I also feel your pain - there is really no excuse for making it so difficult to do a simple thing like opening an existing project. I truly hope that the Eclipse designers focus on making the IDE simpler to use (tho I applaud their efforts at trying different approaches - but please, Eclipse designers, if you are listening, never complicate something simple).

Using the "animated circle" in an ImageView while loading stuff

You can do this by using the following xml

<RelativeLayout
    style="@style/GenericProgressBackground"
    android:id="@+id/loadingPanel"
    >
    <ProgressBar
        style="@style/GenericProgressIndicator"/>
</RelativeLayout>

With this style

<style name="GenericProgressBackground" parent="android:Theme">
    <item name="android:layout_width">fill_parent</item>    
    <item name="android:layout_height">fill_parent</item>
    <item name="android:background">#DD111111</item>    
    <item name="android:gravity">center</item>  
</style>
<style name="GenericProgressIndicator" parent="@android:style/Widget.ProgressBar.Small">
    <item name="android:layout_width">wrap_content</item>
    <item name="android:layout_height">wrap_content</item>
    <item name="android:indeterminate">true</item> 
</style>

To use this, you must hide your UI elements by setting the visibility value to GONE and whenever the data is loaded, call setVisibility(View.VISIBLE) on all your views to restore them. Don't forget to call findViewById(R.id.loadingPanel).setVisiblity(View.GONE) to hide the loading animation.

If you dont have a loading event/function but just want the loading panel to disappear after x seconds use a Handle to trigger the hiding/showing.

Convert a list of characters into a string

This may be the fastest way:

>> from array import array
>> a = ['a','b','c','d']
>> array('B', map(ord,a)).tostring()
'abcd'

Checking if a collection is empty in Java: which is the best method?

To Check collection is empty, you can use method: .count(). Example:

DBCollection collection = mMongoOperation.getCollection("sequence");
    if(collection.count() == 0) {
        SequenceId sequenceId = new SequenceId("id", 0);
        mMongoOperation.save(sequenceId);
    }

Is there an easy way to attach source in Eclipse?

Short answer would be yes.

You can attach source using the properties for a project.

Go to Properties (for the Project) -> Java Build Path -> Libraries

Select the Library you want to attach source/javadoc for and then expand it, you'll see a list like so:

Source Attachment: (none)
Javadoc location: (none)
Native library location: (none)
Access rules: (No restrictions)

Select Javadoc location and then click Edit on the right hahnd side. It should be quite straight forward from there.

Good luck :)

How to get method parameter names?

In CPython, the number of arguments is

a_method.func_code.co_argcount

and their names are in the beginning of

a_method.func_code.co_varnames

These are implementation details of CPython, so this probably does not work in other implementations of Python, such as IronPython and Jython.

One portable way to admit "pass-through" arguments is to define your function with the signature func(*args, **kwargs). This is used a lot in e.g. matplotlib, where the outer API layer passes lots of keyword arguments to the lower-level API.

is there a post render callback for Angular JS directive?

Here is a directive to have actions programmed after a shallow render. By shallow I mean it will evaluate after that very element rendered and that will be unrelated to when its contents get rendered. So if you need some sub element doing a post render action, you should consider using it there:

define(['angular'], function (angular) {
  'use strict';
  return angular.module('app.common.after-render', [])
    .directive('afterRender', [ '$timeout', function($timeout) {
    var def = {
        restrict : 'A', 
        terminal : true,
        transclude : false,
        link : function(scope, element, attrs) {
            if (attrs) { scope.$eval(attrs.afterRender) }
            scope.$emit('onAfterRender')
        }
    };
    return def;
    }]);
});

then you can do:

<div after-render></div>

or with any useful expression like:

<div after-render="$emit='onAfterThisConcreteThingRendered'"></div>

How to compare two strings are equal in value, what is the best method?

== checks to see if they are actually the same object in memory (which confusingly sometimes is true, since they may both be from the pool), where as equals() is overridden by java.lang.String to check each character to ensure true equality. So therefore, equals() is what you want.

window.onload vs document.onload

In Chrome, window.onload is different from <body onload="">, whereas they are the same in both Firefox(version 35.0) and IE (version 11).

You could explore that by the following snippet:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <!--import css here-->
        <!--import js scripts here-->

        <script language="javascript">

            function bodyOnloadHandler() {
                console.log("body onload");
            }

            window.onload = function(e) {
                console.log("window loaded");
            };
        </script>
    </head>

    <body onload="bodyOnloadHandler()">

        Page contents go here.

    </body>
</html>

And you will see both "window loaded"(which comes firstly) and "body onload" in Chrome console. However, you will see just "body onload" in Firefox and IE. If you run "window.onload.toString()" in the consoles of IE & FF, you will see:

"function onload(event) { bodyOnloadHandler() }"

which means that the assignment "window.onload = function(e)..." is overwritten.

Bootstrap how to get text to vertical align in a div container

HTML:

First, we will need to add a class to your text container so that we can access and style it accordingly.

<div class="col-xs-5 textContainer">
     <h3 class="text-left">Link up with other gamers all over the world who share the same tastes in games.</h3>
</div>

CSS:

Next, we will apply the following styles to align it vertically, according to the size of the image div next to it.

.textContainer { 
    height: 345px; 
    line-height: 340px;
}

.textContainer h3 {
    vertical-align: middle;
    display: inline-block;
}

All Done! Adjust the line-height and height on the styles above if you believe that it is still slightly out of align.

WORKING EXAMPLE

Failed to import new Gradle project: failed to find Build Tools revision *.0.0

After spending a few hours: I restarted the Android SDK Manager and at this time I noticed that I got Android SDK Platform-tools (upgrade) and Android SDK Build-tools (new).

After installing those, I was finally able to fully compile my project.

Note: The latest ADT (Version 22) should be installed.

How can I round down a number in Javascript?

You need to put -1 to round half down and after that multiply by -1 like the example down bellow.

<script type="text/javascript">

  function roundNumber(number, precision, isDown) {
    var factor = Math.pow(10, precision);
    var tempNumber = number * factor;
    var roundedTempNumber = 0;
    if (isDown) {
      tempNumber = -tempNumber;
      roundedTempNumber = Math.round(tempNumber) * -1;
    } else {
      roundedTempNumber = Math.round(tempNumber);
    }
    return roundedTempNumber / factor;
  }
</script>

<div class="col-sm-12">
  <p>Round number 1.25 down: <script>document.write(roundNumber(1.25, 1, true));</script>
  </p>
  <p>Round number 1.25 up: <script>document.write(roundNumber(1.25, 1, false));</script></p>
</div>

Reverse a string in Java

All above solution is too good but here I am making reverse string using recursive programming.

This is helpful for who is looking recursive way of doing reverse string.

public class ReversString {

public static void main(String args[]) {
    char s[] = "Dhiral Pandya".toCharArray();
    String r = new String(reverse(0, s));
    System.out.println(r);
}

public static char[] reverse(int i, char source[]) {

    if (source.length / 2 == i) {
        return source;
    }

    char t = source[i];
    source[i] = source[source.length - 1 - i];
    source[source.length - 1 - i] = t;

    i++;
    return reverse(i, source);

}

}

Batch file to map a drive when the folder name contains spaces

net use "m:\Server01\my folder" /USER:mynetwork\Administrator "Mypassword" /persistent:yes

does not work?

How do you get a timestamp in JavaScript?

Get TimeStamp In JavaScript

In JavaScript, a timestamp is the number of milliseconds that have passed since January 1, 1970.

If you don't intend to support < IE8, you can use

new Date().getTime(); + new Date(); and Date.now();

to directly get the timestamp without having to create a new Date object.

To return the required timestamp

new Date("11/01/2018").getTime()

How to add a RequiredFieldValidator to DropDownList control?

If you are using a data source, here's another way to do it without code behind.

Note the following key points:

The ListItem of Value="0" is on the source page, not added in code
The ListItem in the source will be overwritten if you don't include AppendDataBoundItems="true" in the DropDownList
InitialValue="0" tells the validator that this is the value that should fire that validator (as pointed out in other answers)

Example:

<asp:DropDownList ID="ddlType" runat="server" DataSourceID="sdsType"
                  DataValueField="ID" DataTextField="Name" AppendDataBoundItems="true">
    <asp:ListItem Value="0" Text="--Please Select--" Selected="True"></asp:ListItem>
</asp:DropDownList>
<asp:RequiredFieldValidator ID="rfvType" runat="server" ControlToValidate="ddlType" 
                            InitialValue="0" ErrorMessage="Type required"></asp:RequiredFieldValidator>
<asp:SqlDataSource ID="sdsType" runat="server" 
                   ConnectionString='<%$ ConnectionStrings:TESTConnectionString %>'
                   SelectCommand="SELECT ID, Name FROM Type"></asp:SqlDataSource>

Resize iframe height according to content height in it

I just spent the better part of 3 days wrestling with this. I'm working on an application that loads other applications into itself while maintaining a fixed header and a fixed footer. Here's what I've come up with. (I also used EasyXDM, with success, but pulled it out later to use this solution.)

Make sure to run this code AFTER the <iframe> exists in the DOM. Put it into the page that pulls in the iframe (the parent).

// get the iframe
var theFrame = $("#myIframe");
// set its height to the height of the window minus the combined height of fixed header and footer
theFrame.height(Number($(window).height()) - 80);

function resizeIframe() {
    theFrame.height(Number($(window).height()) - 80);
}

// setup a resize method to fire off resizeIframe.
// use timeout to filter out unnecessary firing.
var TO = false;
$(window).resize(function() {
    if (TO !== false) clearTimeout(TO);
    TO = setTimeout(resizeIframe, 500); //500 is time in miliseconds
});

What requests do browsers' "F5" and "Ctrl + F5" refreshes generate?

It is up to the browser but they behave in similar ways.

I have tested FF, IE7, Opera and Chrome.

F5 usually updates the page only if it is modified. The browser usually tries to use all types of cache as much as possible and adds an "If-modified-since" header to the request. Opera differs by sending a "Cache-Control: no-cache".

CTRL-F5 is used to force an update, disregarding any cache. IE7 adds an "Cache-Control: no-cache", as does FF, which also adds "Pragma: no-cache". Chrome does a normal "If-modified-since" and Opera ignores the key.

If I remember correctly it was Netscape which was the first browser to add support for cache-control by adding "Pragma: No-cache" when you pressed CTRL-F5.

Edit: Updated table

The table below is updated with information on what will happen when the browser's refresh-button is clicked (after a request by Joel Coehoorn), and the "max-age=0" Cache-control-header.

Updated table, 27 September 2010

+------------------------------------------------------------+
¦  UPDATED   ¦                Firefox 3.x                    ¦
¦27 SEP 2010 ¦  +--------------------------------------------¦
¦            ¦  ¦             MSIE 8, 7                      ¦
¦ Version 3  ¦  ¦  +-----------------------------------------¦
¦            ¦  ¦  ¦          Chrome 6.0                     ¦
¦            ¦  ¦  ¦  +--------------------------------------¦
¦            ¦  ¦  ¦  ¦       Chrome 1.0                     ¦
¦            ¦  ¦  ¦  ¦  +-----------------------------------¦
¦            ¦  ¦  ¦  ¦  ¦    Opera 10, 9                    ¦
¦            ¦  ¦  ¦  ¦  ¦  +--------------------------------¦
¦            ¦  ¦  ¦  ¦  ¦  ¦                                ¦
+------------+--+--+--+--+--+--------------------------------¦
¦          F5¦IM¦I ¦IM¦IM¦C ¦                                ¦
¦    SHIFT-F5¦- ¦- ¦CP¦IM¦- ¦ Legend:                        ¦
¦     CTRL-F5¦CP¦C ¦CP¦IM¦- ¦ I = "If-Modified-Since"        ¦
¦      ALT-F5¦- ¦- ¦- ¦- ¦*2¦ P = "Pragma: No-cache"         ¦
¦    ALTGR-F5¦- ¦I ¦- ¦- ¦- ¦ C = "Cache-Control: no-cache"  ¦
+------------+--+--+--+--+--¦ M = "Cache-Control: max-age=0" ¦
¦      CTRL-R¦IM¦I ¦IM¦IM¦C ¦ - = ignored                    ¦
¦CTRL-SHIFT-R¦CP¦- ¦CP¦- ¦- ¦                                ¦
+------------+--+--+--+--+--¦                                ¦
¦       Click¦IM¦I ¦IM¦IM¦C ¦ With 'click' I refer to a      ¦
¦ Shift-Click¦CP¦I ¦CP¦IM¦C ¦ mouse click on the browsers    ¦
¦  Ctrl-Click¦*1¦C ¦CP¦IM¦C ¦ refresh-icon.                  ¦
¦   Alt-Click¦IM¦I ¦IM¦IM¦C ¦                                ¦
¦ AltGr-Click¦IM¦I ¦- ¦IM¦- ¦                                ¦
+------------------------------------------------------------+

Versions tested:

Firefox 3.1.6 and 3.0.6 (WINXP)
MSIE 8.0.6001 and 7.0.5730.11 (WINXP)
Chrome 6.0.472.63 and 1.0.151.48 (WINXP)
Opera 10.62 and 9.61 (WINXP)

Notes:

Version 3.0.6 sends I and C, but 3.1.6 opens the page in a new tab, making a normal request with only "I".
Version 10.62 does nothing. 9.61 might do C unless it was a typo in my old table.

Note about Chrome 6.0.472: If you do a forced reload (like CTRL-F5) it behaves like the url is internally marked to always do a forced reload. The flag is cleared if you go to the address bar and press enter.

Difference between 2 dates in SQLite

The SQLite documentation is a great reference and the DateAndTimeFunctions page is a good one to bookmark.

It's also helpful to remember that it's pretty easy to play with queries with the sqlite command line utility:

sqlite> select julianday(datetime('now'));
2454788.09219907
sqlite> select datetime(julianday(datetime('now')));
2008-11-17 14:13:55

How to use npm with node.exe?

Search all .npmrc file in your system.

Please verify that the path you have given is correct. If not please remove the incorrect path.

CharSequence VS String in Java?

I believe it is best to use CharSequence. The reason is that String implements CharSequence, therefore you can pass a String into a CharSequence, HOWEVER you cannot pass a CharSequence into a String, as CharSequence doesn't not implement String. ALSO, in Android the EditText.getText() method returns an Editable, which also implements CharSequence and can be passed easily into one, while not easily into a String. CharSequence handles all!

Correct way of getting Client's IP Addresses from http.Request

This is how I come up with the IP

func ReadUserIP(r *http.Request) string {
    IPAddress := r.Header.Get("X-Real-Ip")
    if IPAddress == "" {
        IPAddress = r.Header.Get("X-Forwarded-For")
    }
    if IPAddress == "" {
        IPAddress = r.RemoteAddr
    }
    return IPAddress
}

X-Real-Ip - fetches first true IP (if the requests sits behind multiple NAT sources/load balancer)
X-Forwarded-For - if for some reason X-Real-Ip is blank and does not return response, get from X-Forwarded-For
Remote Address - last resort (usually won't be reliable as this might be the last ip or if it is a naked http request to server ie no load balancer)

How to get the parent dir location

I tried:

import os
os.path.abspath(os.path.join(os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe()))), os.pardir))

Epoch vs Iteration when training neural networks

In the neural network terminology:

one epoch = one forward pass and one backward pass of all the training examples
batch size = the number of training examples in one forward/backward pass. The higher the batch size, the more memory space you'll need.
number of iterations = number of passes, each pass using [batch size] number of examples. To be clear, one pass = one forward pass + one backward pass (we do not count the forward pass and backward pass as two different passes).

Example: if you have 1000 training examples, and your batch size is 500, then it will take 2 iterations to complete 1 epoch.

FYI: Tradeoff batch size vs. number of iterations to train a neural network

The term "batch" is ambiguous: some people use it to designate the entire training set, and some people use it to refer to the number of training examples in one forward/backward pass (as I did in this answer). To avoid that ambiguity and make clear that batch corresponds to the number of training examples in one forward/backward pass, one can use the term mini-batch.

How do I print out the contents of an object in Rails for easy debugging?

pp does the job too, no gem requiring is required.

@a = Accrual.first ; pp @a

#<Accrual:0x007ff521e5ba50
 id: 4,
 year: 2018,
 Jan: #<BigDecimal:7ff521e58f08,'0.11E2',9(27)>,
 Feb: #<BigDecimal:7ff521e585d0,'0.88E2',9(27)>,
 Mar: #<BigDecimal:7ff521e58030,'0.0',9(27)>,
 Apr: #<BigDecimal:7ff521e53698,'0.88E2',9(27)>,
 May: #<BigDecimal:7ff521e52fb8,'0.8E1',9(27)>,
 June: #<BigDecimal:7ff521e52900,'0.8E1',9(27)>,
 July: #<BigDecimal:7ff521e51ff0,'0.8E1',9(27)>,
 Aug: #<BigDecimal:7ff521e51bb8,'0.88E2',9(27)>,
 Sep: #<BigDecimal:7ff521e512f8,'0.88E2',9(27)>,
 Oct: #<BigDecimal:7ff521e506c8,'0.0',9(27)>,
 Nov: #<BigDecimal:7ff521e43d38,'0.888E3',9(27)>,
 Dec: #<BigDecimal:7ff521e43478,'0.0',9(27)>,

You can also print two instances of an object:

 pp( Accrual.first , Accrual.second)
`
`
`

How to access parent Iframe from JavaScript

Try this, in your parent frame set up you IFRAMEs like this:

<iframe id="frame1" src="inner.html#frame1"></iframe>
<iframe id="frame2" src="inner.html#frame2"></iframe>
<iframe id="frame3" src="inner.html#frame3"></iframe>

Note that the id of each frame is passed as an anchor in the src.

then in your inner html you can access the id of the frame it is loaded in via location.hash:

<button onclick="alert('I am frame: ' + location.hash.substr(1))">Who Am I?</button>

then you can access parent.document.getElementById() to access the iframe tag from inside the iframe

Use RSA private key to generate public key?

My answer below is a bit lengthy, but hopefully it provides some details that are missing in previous answers. I'll start with some related statements and finally answer the initial question.

To encrypt something using RSA algorithm you need modulus and encryption (public) exponent pair (n, e). That's your public key. To decrypt something using RSA algorithm you need modulus and decryption (private) exponent pair (n, d). That's your private key.

To encrypt something using RSA public key you treat your plaintext as a number and raise it to the power of e modulus n:

ciphertext = ( plaintext^e ) mod n

To decrypt something using RSA private key you treat your ciphertext as a number and raise it to the power of d modulus n:

plaintext = ( ciphertext^d ) mod n

To generate private (d,n) key using openssl you can use the following command:

openssl genrsa -out private.pem 1024

To generate public (e,n) key from the private key using openssl you can use the following command:

openssl rsa -in private.pem -out public.pem -pubout

To dissect the contents of the private.pem private RSA key generated by the openssl command above run the following (output truncated to labels here):

openssl rsa -in private.pem -text -noout | less

modulus         - n
privateExponent - d
publicExponent  - e
prime1          - p
prime2          - q
exponent1       - d mod (p-1)
exponent2       - d mod (q-1)
coefficient     - (q^-1) mod p

Shouldn't private key consist of (n, d) pair only? Why are there 6 extra components? It contains e (public exponent) so that public RSA key can be generated/extracted/derived from the private.pem private RSA key. The rest 5 components are there to speed up the decryption process. It turns out that by pre-computing and storing those 5 values it is possible to speed the RSA decryption by the factor of 4. Decryption will work without those 5 components, but it can be done faster if you have them handy. The speeding up algorithm is based on the Chinese Remainder Theorem.

Yes, private.pem RSA private key actually contains all of those 8 values; none of them are generated on the fly when you run the previous command. Try running the following commands and compare output:

# Convert the key from PEM to DER (binary) format
openssl rsa -in private.pem -outform der -out private.der

# Print private.der private key contents as binary stream
xxd -p private.der

# Now compare the output of the above command with output 
# of the earlier openssl command that outputs private key
# components. If you stare at both outputs long enough
# you should be able to confirm that all components are
# indeed lurking somewhere in the binary stream
openssl rsa -in private.pem -text -noout | less

This structure of the RSA private key is recommended by the PKCS#1 v1.5 as an alternative (second) representation. PKCS#1 v2.0 standard excludes e and d exponents from the alternative representation altogether. PKCS#1 v2.1 and v2.2 propose further changes to the alternative representation, by optionally including more CRT-related components.

To see the contents of the public.pem public RSA key run the following (output truncated to labels here):

openssl rsa -in public.pem -text -pubin -noout

Modulus             - n
Exponent (public)   - e

No surprises here. It's just (n, e) pair, as promised.

Now finally answering the initial question: As was shown above private RSA key generated using openssl contains components of both public and private keys and some more. When you generate/extract/derive public key from the private key, openssl copies two of those components (e,n) into a separate file which becomes your public key.

Fixed width buttons with Bootstrap

For your buttons, you can create another CSS selector for those special classes of buttons with a specified min-width and max-width. So if your button is

<button class="save_button">Save</button>

In your Bootstrap CSS file you can create something like

.save_button {
    min-width: 80px;
    max-width: 80px;
}

This way it should always stay 80px even if you have a responsive design.

As far as the right way of extending Bootstrap goes, Take a look at this thread:

Extending Bootstrap

identifier "string" undefined?

#include <string> would be the correct c++ include, also you need to specify the namespace with std::string or more generally with using namespace std;

Can I get Unix's pthread.h to compile in Windows?

Just pick up the TDM-GCC 64x package. (It constains both the 32 and 64 bit versions of the MinGW toolchain and comes within a neat installer.) More importantly, it contains something called the "winpthread" library.

It comprises of the pthread.h header, libwinpthread.a, libwinpthread.dll.a static libraries for both 32-bit and 64-bit and the required .dlls libwinpthread-1.dll and libwinpthread_64-1.dll(this, as of 01-06-2016).

You'll need to link to the libwinpthread.a library during build. Other than that, your code can be the same as for native Pthread code on Linux. I've so far successfully used it to compile a few basic Pthread programs in 64-bit on windows.

Alternatively, you can use the following library which wraps the windows threading API into the pthreads API: pthreads-win32.

The above two seem to be the most well known ways for this.

Hope this helps.

Turn off warnings and errors on PHP and MySQL

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

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

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

Select <a> which href ends with some string

$("a[href*=ABC]").addClass('selected');

sublime text2 python error message /usr/bin/python: can't find 'main' module in ''

Save the .py files before you build in sublime.Such as save the file on desktop or other document.

Can I pass a JavaScript variable to another browser window?

One can pass a message from the 'parent' window to the 'child' window:

in the 'parent window' open the child

    var win = window.open(<window.location.href>, '_blank');    
       setTimeout(function(){
                    win.postMessage(SRFBfromEBNF,"*")
                  },1000);
    win.focus();

the to be replaced according to the context

In the 'child'

    window.addEventListener('message', function(event) {
        if(event.srcElement.location.href==window.location.href){
        /* do what you want with event.data */
        }
    });

The if test must be changed according to the context

Replace all values in a matrix <0.1 with 0

Negative list index?

List indexes of -x mean the xth item from the end of the list, so n[-1] means the last item in the list n. Any good Python tutorial should have told you this.

It's an unusual convention that only a few other languages besides Python have adopted, but it is extraordinarily useful; in any other language you'll spend a lot of time writing n[n.length-1] to access the last item of a list.

Setting dynamic scope variables in AngularJs - scope.<some_string>

If you are ok with using Lodash, you can do the thing you wanted in one line using _.set():

_.set(object, path, value) Sets the property value of path on object. If a portion of path does not exist it’s created.

https://lodash.com/docs#set

So your example would simply be: _.set($scope, the_string, something);

Unit testing with Spring Security

General

In the meantime (since version 3.2, in the year 2013, thanks to SEC-2298) the authentication can be injected into MVC methods using the annotation @AuthenticationPrincipal:

@Controller
class Controller {
  @RequestMapping("/somewhere")
  public void doStuff(@AuthenticationPrincipal UserDetails myUser) {
  }
}

Tests

In your unit test you can obviously call this Method directly. In integration tests using org.springframework.test.web.servlet.MockMvc you can use org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.user() to inject the user like this:

mockMvc.perform(get("/somewhere").with(user(myUserDetails)));

This will however just directly fill the SecurityContext. If you want to make sure that the user is loaded from a session in your test, you can use this:

mockMvc.perform(get("/somewhere").with(sessionUser(myUserDetails)));
/* ... */
private static RequestPostProcessor sessionUser(final UserDetails userDetails) {
    return new RequestPostProcessor() {
        @Override
        public MockHttpServletRequest postProcessRequest(final MockHttpServletRequest request) {
            final SecurityContext securityContext = new SecurityContextImpl();
            securityContext.setAuthentication(
                new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities())
            );
            request.getSession().setAttribute(
                HttpSessionSecurityContextRepository.SPRING_SECURITY_CONTEXT_KEY, securityContext
            );
            return request;
        }
    };
}

How can I access iframe elements with Javascript?

If you have the HTML

<form name="formname" .... id="form-first">
    <iframe id="one" src="iframe2.html">
    </iframe>
</form>

and JavaScript

function iframeRef( frameRef ) {
    return frameRef.contentWindow
        ? frameRef.contentWindow.document
        : frameRef.contentDocument
}

var inside = iframeRef( document.getElementById('one') )

inside is now a reference to the document, so you can do getElementsByTagName('textarea') and whatever you like, depending on what's inside the iframe src.

How Do I Convert an Integer to a String in Excel VBA?

If you have a valid integer value and your requirement is to compare values, you can simply go ahead with the comparison as seen below.

Sub t()

Dim i As Integer
Dim s  As String

' pass
i = 65
s = "65"
If i = s Then
MsgBox i
End If

' fail - Type Mismatch
i = 65
s = "A"
If i = s Then
MsgBox i
End If
End Sub

Directory Chooser in HTML page

If you do not have too many folders then I suggest you use if statements to choose an upload folder depending on the user input details. E.g.

String user= request.getParameter("username");
if (user=="Alfred"){
//Path A;
}
if (user=="other"){
//Path B;
}

Efficient way to return a std::vector in c++

If the compiler supports Named Return Value Optimization (http://msdn.microsoft.com/en-us/library/ms364057(v=vs.80).aspx), you can directly return the vector provide that there is no:

Different paths returning different named objects
Multiple return paths (even if the same named object is returned on all paths) with EH states introduced.
The named object returned is referenced in an inline asm block.

NRVO optimizes out the redundant copy constructor and destructor calls and thus improves overall performance.

There should be no real diff in your example.

Java dynamic array sizes?

Here's a method that doesn't use ArrayList. The user specifies the size and you can add a do-while loop for recursion.

import java.util.Scanner;
    public class Dynamic {
        public static Scanner value;
        public static void main(String[]args){
            value=new Scanner(System.in);
            System.out.println("Enter the number of tests to calculate average\n");
            int limit=value.nextInt();
            int index=0;
            int [] marks=new int[limit];
            float sum,ave;
            sum=0;      
            while(index<limit)
            {
                int test=index+1;
                System.out.println("Enter the marks on test " +test);
                marks[index]=value.nextInt();
                sum+=marks[index];
                index++;
            }
            ave=sum/limit;
            System.out.println("The average is: " + ave);
        }
    }

Excel function to get first word from sentence in other cell

I found this on exceljet.net and works for me:

=LEFT(B4,FIND(" ",B4)-1)

How to trigger SIGUSR1 and SIGUSR2?

terminal 1

dd if=/dev/sda of=debian.img

terminal 2

killall -SIGUSR1 dd

go back to terminal 1

34292201+0 records in
34292200+0 records out
17557606400 bytes (18 GB) copied, 1034.7 s, 17.0 MB/s

For each row return the column name of the largest value

Here is an answer that works with data.table and is simpler. This assumes your data.table is named yourDF:

j1 <- max.col(yourDF[, .(V1, V2, V3, V4)], "first")
yourDF$newCol <- c("V1", "V2", "V3", "V4")[j1]

Replace ("V1", "V2", "V3", "V4") and (V1, V2, V3, V4) with your column names

How to completely remove borders from HTML table

Using TinyMCE editor, the only way I was able to remove all borders was to use border:hidden in the style like this:

<style>
table, tr {border:hidden;}
td, th {border:hidden;}
</style>

And in the HTML like this:

<table style="border:hidden;"</table>

Cheers

jQuery UI autocomplete with JSON

I use this script for autocomplete...

$('#custmoers_name').autocomplete({
    source: function (request, response) {

        // $.getJSON("<?php echo base_url('index.php/Json_cr_operation/autosearch_custmoers');?>", function (data) {
          $.getJSON("Json_cr_operation/autosearch_custmoers?term=" + request.term, function (data) {
          console.log(data);
            response($.map(data, function (value, key) {
                console.log(value);
                return {
                    label: value.label,
                    value: value.value
                };
            }));
        });
    },
    minLength: 1,
    delay: 100
});

My json return :- [{"label":"Mahesh Arun Wani","value":"1"}] after search m

but it display in dropdown [object object]...

What is managed or unmanaged code in programming?

In as few words as possible:

managed code = .NET programs
unmanaged code = "normal" programs

Can you use CSS to mirror/flip text?

You could try box-reflect

box-reflect: 20px right;

see CSS property box-reflect compatibility? for more details

Android Studio: Can't start Git

The path for your git is invalid. Copy the path from File -> Settings -> Version Control -> Git and search that folder and you can see the path to your Git is not valid. Reset the path with correct location and test it. The error should be gone.

Paging UICollectionView by cells, not screen

Here is my way to do it by using a UICollectionViewFlowLayout to override the targetContentOffset:

(Although in the end, I end up not using this and use UIPageViewController instead.)

/**
 A UICollectionViewFlowLayout with...
 - paged horizontal scrolling
 - itemSize is the same as the collectionView bounds.size
 */
class PagedFlowLayout: UICollectionViewFlowLayout {

  override init() {
    super.init()
    self.scrollDirection = .horizontal
    self.minimumLineSpacing = 8 // line spacing is the horizontal spacing in horizontal scrollDirection
    self.minimumInteritemSpacing = 0
    if #available(iOS 11.0, *) {
      self.sectionInsetReference = .fromSafeArea // for iPhone X
    }
  }

  required init?(coder aDecoder: NSCoder) {
    fatalError("not implemented")
  }

  // Note: Setting `minimumInteritemSpacing` here will be too late. Don't do it here.
  override func prepare() {
    super.prepare()
    guard let collectionView = collectionView else { return }
    collectionView.decelerationRate = UIScrollViewDecelerationRateFast // mostly you want it fast!

    let insetedBounds = UIEdgeInsetsInsetRect(collectionView.bounds, self.sectionInset)
    self.itemSize = insetedBounds.size
  }

  // Table: Possible cases of targetContentOffset calculation
  // -------------------------
  // start |          |
  // near  | velocity | end
  // page  |          | page
  // -------------------------
  //   0   | forward  |  1
  //   0   | still    |  0
  //   0   | backward |  0
  //   1   | forward  |  1
  //   1   | still    |  1
  //   1   | backward |  0
  // -------------------------
  override func targetContentOffset( //swiftlint:disable:this cyclomatic_complexity
    forProposedContentOffset proposedContentOffset: CGPoint, withScrollingVelocity velocity: CGPoint) -> CGPoint {

    guard let collectionView = collectionView else { return proposedContentOffset }

    let pageWidth = itemSize.width + minimumLineSpacing
    let currentPage: CGFloat = collectionView.contentOffset.x / pageWidth
    let nearestPage: CGFloat = round(currentPage)
    let isNearPreviousPage = nearestPage < currentPage

    var pageDiff: CGFloat = 0
    let velocityThreshold: CGFloat = 0.5 // can customize this threshold
    if isNearPreviousPage {
      if velocity.x > velocityThreshold {
        pageDiff = 1
      }
    } else {
      if velocity.x < -velocityThreshold {
        pageDiff = -1
      }
    }

    let x = (nearestPage + pageDiff) * pageWidth
    let cappedX = max(0, x) // cap to avoid targeting beyond content
    //print("x:", x, "velocity:", velocity)
    return CGPoint(x: cappedX, y: proposedContentOffset.y)
  }

}

allowing only alphabets in text box using java script

From kosare comments, i have create an demo http://jsbin.com/aTUMeMAV/2/

HTML

      <form name="f" onsubmit="return onlyAlphabets()">
         <input type="text" name="nm">
         <div id="notification"></div>
         <input type="submit">
      </form>

javascript

  function onlyAlphabets() {

  var regex = /^[a-zA-Z]*$/;
  if (regex.test(document.f.nm.value)) {

      //document.getElementById("notification").innerHTML = "Watching.. Everything is Alphabet now";
      return true;
  } else {
      document.getElementById("notification").innerHTML = "Alphabets Only";
      return false;
  }


}

java.io.StreamCorruptedException: invalid stream header: 7371007E

If you are sending multiple objects, it's often simplest to put them some kind of holder/collection like an Object[] or List. It saves you having to explicitly check for end of stream and takes care of transmitting explicitly how many objects are in the stream.

EDIT: Now that I formatted the code, I see you already have the messages in an array. Simply write the array to the object stream, and read the array on the server side.

Your "server read method" is only reading one object. If it is called multiple times, you will get an error since it is trying to open several object streams from the same input stream. This will not work, since all objects were written to the same object stream on the client side, so you have to mirror this arrangement on the server side. That is, use one object input stream and read multiple objects from that.

(The error you get is because the objectOutputStream writes a header, which is expected by objectIutputStream. As you are not writing multiple streams, but simply multiple objects, then the next objectInputStream created on the socket input fails to find a second header, and throws an exception.)

To fix it, create the objectInputStream when you accept the socket connection. Pass this objectInputStream to your server read method and read Object from that.

JavaScript - populate drop down list with array

I found this also works...

var select = document.getElementById("selectNumber"); 
var options = ["1", "2", "3", "4", "5"]; 

// Optional: Clear all existing options first:
select.innerHTML = "";
// Populate list with options:
for(var i = 0; i < options.length; i++) {
    var opt = options[i];
    select.innerHTML += "<option value=\"" + opt + "\">" + opt + "</option>";
}

Bootstrap 3 truncate long text inside rows of a table in a responsive way

I'm using bootstrap.
I used css parameters.

.table {
  table-layout:fixed;
}

.table td {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

and bootstrap grid system parameters, like this.

<th class="col-sm-2">Name</th>

<td class="col-sm-2">hoge</td>

Remove directory which is not empty

Just use rmdir module! it's easy and simple.

How do you properly use namespaces in C++?

I prefer using a top-level namespace for the application and sub namespaces for the components.

The way you can use classes from other namespaces is surprisingly very similar to the way in java. You can either use "use NAMESPACE" which is similar to an "import PACKAGE" statement, e.g. use std. Or you specify the package as prefix of the class separated with "::", e.g. std::string. This is similar to "java.lang.String" in Java.

Linq to Entities - SQL "IN" clause

You need to turn it on its head in terms of the way you're thinking about it. Instead of doing "in" to find the current item's user rights in a predefined set of applicable user rights, you're asking a predefined set of user rights if it contains the current item's applicable value. This is exactly the same way you would find an item in a regular list in .NET.

There are two ways of doing this using LINQ, one uses query syntax and the other uses method syntax. Essentially, they are the same and could be used interchangeably depending on your preference:

Query Syntax:

var selected = from u in users
               where new[] { "Admin", "User", "Limited" }.Contains(u.User_Rights)
               select u

foreach(user u in selected)
{
    //Do your stuff on each selected user;
}

Method Syntax:

var selected = users.Where(u => new[] { "Admin", "User", "Limited" }.Contains(u.User_Rights));

foreach(user u in selected)
{
    //Do stuff on each selected user;
}

My personal preference in this instance might be method syntax because instead of assigning the variable, I could do the foreach over an anonymous call like this:

foreach(User u in users.Where(u => new [] { "Admin", "User", "Limited" }.Contains(u.User_Rights)))
{
    //Do stuff on each selected user;
}

Syntactically this looks more complex, and you have to understand the concept of lambda expressions or delegates to really figure out what's going on, but as you can see, this condenses the code a fair amount.

It all comes down to your coding style and preference - all three of my examples do the same thing slightly differently.

An alternative way doesn't even use LINQ, you can use the same method syntax replacing "where" with "FindAll" and get the same result, which will also work in .NET 2.0:

foreach(User u in users.FindAll(u => new [] { "Admin", "User", "Limited" }.Contains(u.User_Rights)))
{
    //Do stuff on each selected user;
}

What is a web service endpoint?

In past projects I worked on, the endpoint was a relative property. That is to say it may or may not have been appended to, but it always contained the protocol://host:port/partOfThePath.

If the service being called had a dynamic part to it, for example a ?param=dynamicValue, then that part would get added to the endpoint. But many times the endpoint could be used as is without having to be amended.

Whats important to understand is what an endpoint is not and how it helps. For example an alternative way to pass the information stored in an endpoint would be to store the different parts of the endpoint in separate properties. For example:

hostForServiceA=someIp
portForServiceA=8080
pathForServiceA=/some/service/path
hostForServiceB=someIp
portForServiceB=8080
pathForServiceB=/some/service/path

Or if the same host and port across multiple services:

host=someIp
port=8080
pathForServiceA=/some/service/path
pathForServiceB=/some/service/path

In those cases the full URL would need to be constructed in your code as such:

String url = "http://" + host + ":" + port + pathForServiceA  + "?" + dynamicParam + "=" + dynamicValue;

In contract this can be stored as an endpoint as such

serviceAEndpoint=http://host:port/some/service/path?dynamicParam=

And yes many times we stored the endpoint up to and including the '='. This lead to code like this:

String url = serviceAEndpoint + dynamicValue;

Hope that sheds some light.

How to find the foreach index?

I would like to add this, I used this in laravel to just index my table:

With $loop->index
I also preincrement it with ++$loop to start at 1

My Code:

@foreach($resultsPerCountry->first()->studies as $result)
  <tr>
    <td>{{ ++$loop->index}}</td>                                    
  </tr>
@endforeach

Cannot ping AWS EC2 instance

Please go through the below checklists

1) You have to first check whether the instance is launched in a subnet where it is reachable from the internet

For that check whether the instance launched subnet has an internet gateway attached to it.For details of networking in AWS please go through the below link.

public and private subnets in aws vpc

2) Check whether you have proper security group rules added,If notAdd the below rule in the security group attached to instance.A Security group is firewall attached to every instance launched.The security groups contain the inbound/outbound rules which allow the traffic in/out of the instance.by default every security group allow all outbound traffic from the instance and no inbound traffic to the instance.Check the below link for more details of the traffic.

security group documentation

Type: custom ICMPV4

Protocol: ICMP

Portrange : Echo Request

Source: 0.0.0.0/0

screenshot from aws console

3) Check whether you have the enough rules in the subnet level firewall called NACL.An NACL is a stateless firewall which needs both inbound and outbound traffic separately specified.NACL is applied at the subnet level, all the instances under the subnet will come under the NACL rules.Below is the link which will have more details on it.

NACL documentation

Inbound Rules . Outbound Rules

Type: Custom IPV4 Type: Custom IPV4

Protocol: ICMP Protocol: ICMP

Portrange: ECHO REQUEST Portrange: ECHO REPLY

Source: 0.0.0.0/0 Destination: 0.0.0.0/0

Allow/Deny: Allow Allow/Deny: Allow

screenshot inbound rule

screenshot outbound rule

4) check any firewalls like IPTABLES and disble for testing the ping.

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