Tutorial by Examples: r

If you want to measure benchmarks add a testing method like this: sum.go: package sum // Sum calculates the sum of two integers func Sum(a, b int) int { return a + b } sum_test.go: package sum import "testing" func BenchmarkSum(b *testing.B) { for i := 0; i < ...

This type of testing is popular technique for testing with predefined input and output values. Create a file called main.go with content: package main import ( "fmt" ) func main() { fmt.Println(Sum(4, 5)) } func Sum(a, b int) int { return a + b } After you r...

SelectorDescription*Universal selector (all elements)divTag selector (all <div> elements).blueClass selector (all elements with class blue).blue.redAll elements with class blue and red (a type of Compound selector)#headlineID selector (the element with "id" attribute set to headline)...

Here is a simple model that we will use to run a few test queries: class MyModel(models.Model): name = models.CharField(max_length=10) model_num = models.IntegerField() flag = models.NullBooleanField(default=False) Get a single model object where the id/pk is 4: (If there are no...

Context processor to determine the template based on group membership(or any query/logic). This allows our public/regular users to get one template and our special group to get a different one. myapp/context_processors.py def template_selection(request): site_template = 'template_public.html...

Conditions may also be evaluated in a single line using the ternary operator: If you wanted to determine the minimum and maximum of two variables, you could use if statements, like so: let a = 5 let b = 10 let min: Int if a < b { min = a } else { min = b } let max: Int ...

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. ...

Using Playground it is easy to see that happens inside loops or objects while the change is happening. For example, in the code below, the value of x will change from 1 to 4. import UIKit for x in [1, 2, 3, 4] { x } (1) Clicking on the eye symbol on the right will give us a quick look. (2...

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...

The ls command's -S option sorts the files in descending order of file size. $ ls -l -S ./Fruits total 444 -rw-rw-rw- 1 root root 295303 Jul 28 19:19 apples.jpg -rw-rw-rw- 1 root root 102283 Jul 28 19:19 kiwis.jpg -rw-rw-rw- 1 root root 50197 Jul 28 19:19 bananas.jpg When used with the -r o...

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...

Go supports pointers, allowing you to pass references to values and records within your program. package main import "fmt" // We'll show how pointers work in contrast to values with // 2 functions: `zeroval` and `zeroptr`. `zeroval` has an // `int` parameter, so arguments will be ...

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 }; }

OptionSetType is a protocol designed to represent bit mask types where individual bits represent members of the set. A set of logical and/or functions enforce the proper syntax: struct Features : OptionSet { let rawValue : Int static let none = Features(rawValue: 0) static let feature0 = F...

You can create an ordered dictionary which will follow a determined order when iterating over the keys in the dictionary. Use OrderedDict from the collections module. This will always return the dictionary elements in the original insertion order when iterated over. from collections import Ordere...

Array.isArray(obj) returns true if the object is an Array, otherwise false. Array.isArray([]) // true Array.isArray([1, 2, 3]) // true Array.isArray({}) // false Array.isArray(1) // false In most cases you can instanceof to check if an object is an Array. []...

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...

function themeSlug_enqueue_scripts() { wp_enqueue_style( 'themeSlug-reset', get_template_directory_uri() .'/css/reset.css', '1.0.0' ); wp_enqueue_style( 'themeSlug-style', get_template_directory_uri() .'/style.css', 'themeSlug-reset', '1.0.0'); } add_action('wp_enqueue_scripts', 'themeSl...

In this case style.css is located in root of the theme's folder function themeSlug_enqueue_scripts() { wp_enqueue_style( 'themeSlug-style', get_template_directory_uri() .'/style.css', '1.0.0'); } add_action('wp_enqueue_scripts', 'themeSlug_enqueue_scripts');

In this example we want to include font awesome icon font function themeSlug_enqueue_scripts() { wp_enqueue_style( 'font-awesome', '//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.6.3/css/font-awesome.css'); } add_action('wp_enqueue_scripts', 'themeSlug_enqueue_scripts');