Tutorial by Examples: co

class PostsController < ApplicationController before_action :set_post, only: [:show, :edit, :update, :destroy] def index @posts = Post.all end def show end def new @post = Post.new end def edit end def create @post = Post.new(post_par...

Number of unique elements in a series: In [1]: id_numbers = pd.Series([111, 112, 112, 114, 115, 118, 114, 118, 112]) In [2]: id_numbers.nunique() Out[2]: 5 Get unique elements in a series: In [3]: id_numbers.unique() Out[3]: array([111, 112, 114, 115, 118], dtype=int64) In [4]: df = pd.Da...

You can get list of available commands by following way: >>> python manage.py help If you don't understand any command or looking for optional arguments then you can use -h argument like this >>> python manage.py command_name -h Here command_name will be your desire command...

Example for continue for i in [series] do command 1 command 2 if (condition) # Condition to jump over command 3 continue # skip to the next value in "series" fi command 3 done Example for break for i in [series] do command 4 if (condi...

cond do 0 == 1 -> IO.puts "0 = 1" 2 == 1 + 1 -> IO.puts "1 + 1 = 2" 3 == 1 + 2 -> IO.puts "1 + 2 = 3" end # Outputs "1 + 1 = 2" (first condition evaluating to true) cond will raise a CondClauseError if no conditions are true. co...

CountDownLatch A synchronization aid that allows one or more threads to wait until a set of operations being performed in other threads completes. A CountDownLatch is initialized with a given count. The await methods block until the current count reaches zero due to invocations of the count...

Say we have this code snippet. class A { public: int a; int b; A(const A &other) { this->a = other.a; this->b = other.b; } }; To create a copy constructor, that is, to make a function that copies an object and creates a new one, we norma...

Simple constraint: interface IRunnable { run(): void; } interface IRunner<T extends IRunnable> { runSafe(runnable: T): void; } More complex constraint: interface IRunnble<U> { run(): U; } interface IRunner<T extends IRunnable<U>, U> { runSafe...

Similar to using an Object Declaration, you can define the main function of a Kotlin program using a Companion Object of a class. package my.program class App { companion object { @JvmStatic fun main(args: Array<String>) { println("Hello World") ...

This query will return all COLUMNS and their associated TABLES for a given column name. It is designed to show you what tables (unknown) contain a specified column (known) SELECT c.name AS ColName, t.name AS TableName FROM sys.columns c JOIN sys.tables t ON c.object_id = t.o...

$this->helper('customer/data')->getAccountUrl(); OR Mage::helper('customer/data')->getAccountUrl();

The easiest way to get started with Gremlin is to install the Gremlin Console. The Gremlin Console is a REPL that allows immediate feedback on the results of Gremlin traversals. As a prerequisite, Java 8 is required for the Gremlin Console to run. Ensure that it is installed prior to moving forward...

If you ever wanted to determine the html content to be printed on a page during run time then, rails has a very good solution for that. It has something called the content_for which allows us to pass a block to a rails view. Please check the below example, Declare content_for <div> <%=...

Accessibility of symbols declared in a module can be controlled using private and public attributes and statement. Syntax of the statement form: !all symbols declared in the module are private by default private !all symbols declared in the module are public by default public !symbols in t...

Drupal Console The new CLI for Drupal. A tool to generate boilerplate code, interact with and debug Drupal. First, we need to install Drupal Console. Drupal Console is needed not only for this time, but for future installations. # Run this in your terminal to get the latest project version: cur...

Comparable types are primitive types that can be compared using comparison operators from Basics module, like: (<), (>), (<=), (>=), max, min, compare Comparable types in Elm are Int, Float, Time, Char, String, and tuples or lists of comparable types. In documentation or type definitio...

Record is a set of key-value pairs. greeter = { isMorning: True , greeting: "Good morning!" } It is impossible to access a value by an non-existent key. It is impossible to dynamically modify Record's structure. Records only allow you to update values by constant keys....

Given a file file.txt with the following content: line 1 line 2 line 3 You can delete a line from file content with the d command. The pattern to match is surrounded with default / delimiter and the d command follows the pattern: sed '/line 2/d' file.txt The above command will output: l...

If you set opacity on an element it will affect all its child elements. To set an opacity just on the background of an element you will have to use RGBA colors. Following example will have a black background with 0.6 opacity. /* Fallback for web browsers that don't support RGBa */ background-color...

Objective-C mySwitch.backgroundColor = [UIColor yellowColor]; [mySwitch setBackgroundColor: [UIColor yellowColor]]; mySwitch.backgroundColor =[UIColor colorWithRed:255/255.0 green:0/255.0 blue:0/255.0 alpha:1.0]; mySwitch.backgroundColor= [UIColor colorWithWhite: 0.5 alpha: 1.0]; mySwitch.backg...