Tutorial by Examples: l

Remove, delete and cleanup containers

docker rm can be used to remove a specific containers like this: docker rm <container name or id> To remove all containers you can use this expression: docker rm $(docker ps -qa) By default docker will not delete a container that is running. Any container that is running will produce a...

Docker • Managing containers

normalize.css

Browsers have a default set of CSS styles they use for rendering elements. Some of these styles can even be customised using the browser's settings to change default font face and size definitions, for example. The styles contain the definition of which elements are supposed to be block-level or inl...

CSS • Normalizing Browser Styles

List packages

Prints all packages, optionally only those whose package name contains the text in <FILTER>. adb shell pm list packages [options] <FILTER> All <FILTER> adb shell pm list packages Attributes: -f to see their associated file. -i See the installer for the packages. -u to ...

Android • adb shell

Declaring and initializing constants

You can initialize a constant by using the const keyword. const foo = 100; const bar = false; const person = { name: "John" }; const fun = function () = { /* ... */ }; const arrowFun = () => /* ... */ ; Important You must declare and initialize a constant in the same statement....

JavaScript • Declarations and Assignments

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

Space Views Evenly

It is common to want two views to be side by side, centered in their superview. The common answer given on Stack Overflow is to embed these two views in a UIView and center the UIView. This is not necessary or recommended. From the UILayoutGuide docs: There are a number of costs associated with...

iOS • Auto Layout

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

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

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

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

File I/O

Files opened in a non-binary mode (e.g. 'r' or 'w') deal with strings. The deafult encoding is 'utf8'. open(fn, mode='r') # opens file for reading in utf8 open(fn, mode='r', encoding='utf16') # opens file for reading utf16 # ERROR: cannot write bytes when a string is expecte...

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

Change list

Let's say you have a simple myblog app with the following model: from django.conf import settings from django.utils import timezone class Article(models.Model): title = models.CharField(max_length=70) slug = models.SlugField(max_length=70, unique=True) author = models.ForeignKe...

Django • Administration

Class Based Views

Class based views let you focus on what make your views special. A static about page might have nothing special, except the template used. Use a TemplateView! All you have to do is set a template name. Job done. Next. views.py from django.views.generic import TemplateView class AboutView(Tem...

Django • Class based views

List and Details views

Template views are fine for static page and you could use them for everything with get_context_data but it would be barely better than using function as views. Enter ListView and DetailView app/models.py from django.db import models class Pokemon(models.Model): name = models.CharField(max...

Django • Class based views