Tutorial by Examples: v

Each enum class contains an implicit static method named values(). This method returns an array containing all values of that enum. You can use this method to iterate over the values. It is important to note however that this method returns a new array every time it is called. public enum Day { ...

Lambda expressions can be used to handle events, which is useful when: The handler is short. The handler never needs to be unsubscribed. A good situation in which a lambda event handler might be used is given below: smtpClient.SendCompleted += (sender, args) => Console.WriteLine("Ema...

The android:process field defines the name of the process where the service is to run. Normally, all components of an application run in the default process created for the application. However, a component can override the default with its own process attribute, allowing you to spread your applicat...

Given the model: class MyModel(models.Model): name = models.CharField(max_length=10) model_num = models.IntegerField() flag = models.NullBooleanField(default=False) We can use Q objects to create AND , OR conditions in your lookup query. For example, say we want all objects that ...

Assuming a class from django.db import models class Author(models.Model): name = models.CharField(max_length=50) def __str__(self): return self.name def get_absolute_url(self): return reverse('view_author', args=[str(self.id)]) class Book(models.Mo...

tl;dr : Create a base class that defines two user objects (say user and another_user). Create your other models and define three Client instances. self.client : Representing user logged in browser self.another_client : Representing another_user 's client self.unlogged_client : Representing unlo...

To run a container interactively, pass in the -it options: $ docker run -it ubuntu:14.04 bash root@8ef2356d919a:/# echo hi hi root@8ef2356d919a:/# -i keeps STDIN open, while -t allocates a pseudo-TTY.

package main import ( "log" "text/template" "os" ) type Person struct{ MyName string MyAge int } var myTempContents string= ` This person's name is : {{.MyName}} And he is {{.MyAge}} years old. ` func main() { t,err := temp...

To assign variables from the command-line, -v can be used: $ awk -v myvar="hello" 'BEGIN {print myvar}' hello Note that there are no spaces around the equal sign. This allows to use shell variables: $ shell_var="hello" $ awk -v myvar="$shell_var" 'BEGIN {print m...

Node Version Manager, otherwise known as nvm, is a bash script that simplifies the management of multiple Node.js versions. To install nvm, use the provided install script: $ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.3/install.sh | bash For windows there is a nvm-windows p...

This magic method is called when user tries to invoke object as a function. Possible use cases may include some approaches like functional programming or some callbacks. class Invokable { /** * This method will be called if object will be executed like a function: * * $invo...

With Blade, you can also include partial views (called 'partials') directly into a page like so: @include('includes.info', ['title' => 'Information Station']) The code above will include the view at 'views/includes/info.blade.php'. It will also pass in a variable $title having value 'Informat...

The most "popular" way of reversing a string in JavaScript is the following code fragment, which is quite common: function reverseString(str) { return str.split('').reverse().join(''); } reverseString('string'); // "gnirts" However, this will work only so long as ...

You can archive different Textsizes inside a Textview with a Span TextView textView = (TextView) findViewById(R.id.textView); Spannable span = new SpannableString(textView.getText()); span.setSpan(new RelativeSizeSpan(0.8f), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); textView.setText(span)...

There are several ways to create an Observable in RxJava. The most powerful way is to use the Observable.create method. But it's also the most complicated way. So you must avoid using it, as much as possible. Emitting an exiting value If you already have a value, you can use Observable.just to emi...

Create a class which extends Service class and in overridden method onBind return your local binder instance: public class LocalService extends Service { // Binder given to clients private final IBinder mBinder = new LocalBinder(); /** * Class used for the client Binder. Bec...

Describe your service access interface through .aidl file: // IRemoteService.aidl package com.example.android; // Declare any non-default types here with import statements /** Example service interface */ interface IRemoteService { /** Request the process ID of this service, to do evil...

You may pull (download) files from the device by executing the following command: adb pull <remote> <local> For example: adb pull /sdcard/ ~/ You may also push (upload) files from your computer to the device: adb push <local> <remote> For example: adb push ~/im...

You can reboot your device by executing the following command: adb reboot Perform this command to reboot into bootloader: adb reboot bootloader Reboot to recovery mode: adb reboot recovery Be aware that the device won't shutdown first!

int[] arr = new int[] { 0, 10, 20, 30}; // Get Console.WriteLine(arr[2]); // 20 // Set arr[2] = 100; // Get the updated value Console.WriteLine(arr[2]); // 100