Tutorial by Examples: w

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...

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...

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...

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...

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...

To start a new thread: use std::thread; fn main() { thread::spawn(move || { // The main thread will not wait for this thread to finish. That // might mean that the next println isn't even executed before the // program exits. println!("Hello from spa...

You can create a tuple and use a switch like so: var str: String? = "hi" var x: Int? = 5 switch (str, x) { case (.Some,.Some): print("Both have values") case (.Some, nil): print("String has a value") case (nil, .Some): print("Int has a value&...

The simple answer is that it allows you to evolve an existing interface without breaking existing implementations. For example, you have Swim interface that you published 20 years ago. public interface Swim { void backStroke(); } We did a great job, our interface is very popular, there ar...

Many-to-One Relationship from django.db import models class Author(models.Model): name = models.CharField(max_length=50) #Book has a foreignkey (many to one) relationship with author class Book(models.Model): author = models.ForeignKey(Author, on_delete=models.CASCADE) publish_...

While the math.sqrt function is provided for the specific case of square roots, it's often convenient to use the exponentiation operator (**) with fractional exponents to perform nth-root operations, like cube roots. The inverse of an exponentiation is exponentiation by the exponent's reciprocal. S...

The most simple example of widget is custom text input. For instance, to create an <input type="tel">, you have to subclass TextInput and set input_type to 'tel'. from django.forms.widgets import TextInput class PhoneInput(TextInput): input_type = 'tel'

You can create widgets composed of multiple widgets using MultiWidget. from datetime import date from django.forms.widgets import MultiWidget, Select from django.utils.dates import MONTHS class SelectMonthDateWidget(MultiWidget): """This widget allows the user to fill in ...

Many C interfaces such as SDL2 have their own deletion functions. This means that you cannot use smart pointers directly: std::unique_ptr<SDL_Surface> a; // won't work, UNSAFE! Instead, you need to define your own deleter. The examples here use the SDL_Surface structure which should be fre...

To demystify Template Haskell, suppose you have data Example a = Example { _foo :: Int, _bar :: a } then makeLenses 'Example produces (more or less) foo :: Lens' (Example a) Int bar :: Lens (Example a) (Example b) a b There's nothing particularly magical going on, though. You can write ...

Create a new playground file: First option: From Xcode welcome screen, select the first option (Get started with a playground). Second option: From menu select File → New → Playground (⌥⇧⌘N). Name your playground and select the platform (iOS/macOS/tvOS), then click Next. ...

models.py : from __future__ import unicode_literals from django.db import models from django.contrib.auth.models import ( AbstractBaseUser, BaseUserManager, PermissionsMixin) from django.utils import timezone from django.utils.translation import ugettext_lazy as _ class UserManage...

Install gunicorn pip install gunicorn From django project folder (same folder where manage.py resides), run the following command to run current django project with gunicorn gunicorn [projectname].wsgi:application -b 127.0.0.1:[port number] You can use the --env option to set the pat...

public IEnumerable<int> F1() { for (int i = 0; i < 3; i++) yield return i; //return F2(); // Compile Error!! foreach (var element in F2()) yield return element; } public int[] F2() { return new[] { 3, 4, 5 }; }

The standard ADB configuration involves a USB connection to a physical device. If you prefer, you can switch over to TCP/IP mode, and connect ADB via WiFi instead. Not rooted device Get on the same network: Make sure your device and your computer are on the same network. Connect the...

This technique works even when the container's dimensions are unknown. Set up a "ghost" element inside the container to be centered that is 100% height, then use vertical-align: middle on both that and the element to be centered. CSS /* This parent can be any width and height */ .block...