Tutorial by Examples: r

Push a specific object to a remote branch

General syntax git push <remotename> <object>:<remotebranchname> Example git push origin master:wip-yourname Will push your master branch to the wip-yourname branch of origin (most of the time, the repository you cloned from). Delete remote branch Deleting the remote br...

Git • Pushing

Granting & revoking API 23+ permissions

A one-liner that helps granting or revoking vulnerable permissions. granting adb shell pm grant <sample.package.id> android.permission.<PERMISSION_NAME> revoking adb shell pm revoke <sample.package.id> android.permission.<PERMISSION_NAME> Granting all run...

Android • adb shell

Print application data

This command print all relevant application data: version code version name granted permissions (Android API 23+) etc.. adb shell dumpsys package <your.package.id>

Android • adb shell

Hello World

Without JSX Here's a basic example that uses React's main API to create a React element and the React DOM API to render the React element in the browser. <!DOCTYPE html> <html> <head> <meta charset="UTF-8" /> <title>Hello React!</title> ...

React • Getting started with React

Infinity and NaN ("not a number")

In all versions of Python, we can represent infinity and NaN ("not a number") as follows: pos_inf = float('inf') # positive infinity neg_inf = float('-inf') # negative infinity not_a_num = float('nan') # NaN ("not a number") In Python 3.5 and higher, we can also us...

Python Language • Math Module

Iterating over a list

Python supports using a for loop directly on a list: my_list = ['foo', 'bar', 'baz'] for item in my_list: print(item) # Output: foo # Output: bar # Output: baz You can also get the position of each item at the same time: for (index, item) in enumerate(my_list): print('The item i...

Python Language • List

Create a "Please wait..." popup

This code can be added to any event like a listener, button, etc. A blocking JDialog will appear and will remain until the process is complete. final JDialog loading = new JDialog(parentComponent); JPanel p1 = new JPanel(new BorderLayout()); p1.add(new JLabel("Please wait..."), BorderLa...

swing • Basics

Raw HTML

The double mustaches interprets the data as plain text, not HTML. In order to output real HTML, you will need to use triple mustaches: <div>{{{ raw_html }}}</div> The contents are inserted as plain HTML - data bindings are ignored. If you need to reuse template pieces, you should use...

Vue.js • Data Binding

Attributes

Mustaches can also be used inside HTML attributes: <div id="item-{{ id }}"></div> Note that attribute interpolations are disallowed in Vue.js directives and special attributes. Don’t worry, Vue.js will raise warnings for you when mustaches are used in wrong places.

Vue.js • Data Binding

Filters

Vue.js allows you to append optional “filters” to the end of an expression, denoted by the “pipe” symbol: {{ message | capitalize }} Here we are “piping” the value of the message expression through the built-in capitalize filter, which is in fact just a JavaScript function that returns the capit...

Vue.js • Data Binding

Hello World

class Greeter { greeting: string; constructor(message: string) { this.greeting = message; } greet(): string { return this.greeting; } }; let greeter = new Greeter("Hello, world!"); console.log(greeter.greet()); Here we have a class, Gree...

TypeScript • Getting started with TypeScript

Rectangles

You can use the clearRect method to clear any rectangular section of the canvas. // Clear the entire canvas ctx.clearRect(0, 0, canvas.width, canvas.height); Note: clearRect is dependent on the transformation matrix. To deal with this, it's possible to reset the transformation matrix befor...

html5-canvas • Clearing the screen

Installation or Setup

GitHub is a huge collection of Git repositories. In other words, you can think of GitHub as a collection of many projects! Creating An Account Visit GitHub's main page Here Pick a username, enter in your email address, and pick a secure password and you're ready to go! Useful Tools For Git/...

github • Getting started with github

Character Guide

Note that some syntax elements have different behavior depending on the expression. SyntaxDescription?Match the preceding character or subexpression 0 or 1 times. Also used for non-capturing groups, and named capturing groups.*Match the preceding character or subexpression 0 or more times.+Match th...

Regular Expressions • Getting started with Regular Expressions

Running tests

Basic Usage cargo test Show program output cargo test -- --nocapture Run specific example cargo test test_name

Rust • Cargo

Encoding/decoding error handling

.encode and .decode both have error modes. The default is 'strict', which raises exceptions on error. Other modes are more forgiving. Encoding >>> "£13.55".encode('ascii', errors='replace') b'?13.55' >>> "£13.55".encode('ascii', errors='ignore') b'13.55' ...

Python Language • Unicode and bytes

ModelForm Example

Create a ModelForm from an existing Model class, by subclassing ModelForm: from django import forms class OrderForm(forms.ModelForm): class Meta: model = Order fields = ['item', 'order_date', 'customer', 'status']

Django • Forms

Form and object creation

Writing a view to create object can be quite boring. You have to display a form, you have to validate it, you have to save the item or return the form with an error. Unless you use one of the generic editing views. app/views.py from django.core.urlresolvers import reverse_lazy from django.views.g...

Django • Class based views

Creating a random user password

In order to create a random user password we can use the symbols provided in the string module. Specifically punctuation for punctuation symbols, ascii_letters for letters and digits for digits: from string import punctuation, ascii_letters, digits We can then combine all these symbols in a name...

Python Language • Random module

Simple interface

In Go, an interface is just a set of methods. We use an interface to specify a behavior of a given object. type Painter interface { Paint() } The implementing type need not declare that it is implementing the interface. It is enough to define methods of the same signature. type Rembrandt ...

Go • Interfaces