Ruby

Enumerable, hashes and blocks for concise Ruby programs.

Values and collections

name = "Ada"Bind a string

names = ["Ada", "Lin"]Create an array

user = { name: "Ada", id: 1 }Create a symbol-keyed hash

user.fetch(:role, "reader")Read with an explicit fallback

[1, 2, 3].map { |n| n * 2 }Transform elements

[1, 2, 3].select { |n| n.odd? }Filter by a predicate

[1, 2, 3].sumSum numeric elements

names.each_with_index { |name, i| puts "#{i}: #{name}" }Iterate with positions

def add(a, b); a + b; endReturn the final expression of a method

File.read("notes.txt")Read a file into a string

File.foreach("notes.txt") { |line| puts line }Iterate through lines

ruby -c app.rbCheck source syntax