things.each do |item| # for each things in things do something while storing that things in the variable item

  print “#{item}"

end

Four good ruby cheat Sheets:

https://overapi.com/ruby

http://www.testingeducation.org/conference/wtst3_pettichord9.pdf

https://github.com/ThibaultJanBeyer/cheatsheets/blob/master/Ruby-Cheatsheet.md#basics

https://www.vikingcodeschool.com/professional-development-with-ruby/ruby-cheat-sheet

def greeting(hello, *names) # *name is a splat argument, takes several parameters passed in an array

  return "#{hello}, #{names}"

end

​

start = greeting("Hi", "Justin", "Maria", "Herbert") # call a method by name

​

def name(variable=default)

  ### The last line in here get's returned by default

end

MY_CONSTANT = # something

my_array = [a,b,c,d,e]

my_array[1] # b

my_array[2..-1] # c , d , e

multi_d = [[0,1],[0,1]]

[1, 2, 3] << 4 # [1, 2, 3, 4] same as [1, 2, 3].push(4)

hash = { "key1" => "value1", "key2" => "value2" } # same as objects in JavaScript

hash = { key1: "value1", key2: "value2" } # the same hash using symbols instead of strings

my_hash = Hash.new # same as my_hash = {} – set a new key like so: pets["Stevie"] = "cat"

pets["key1"] # value1

pets["Stevie"] # cat

my_hash = Hash.new("default value")

hash.select{ |key, value| value > 3 } # selects all keys in hash that have a value greater than 3

hash.each_key { |k| print k, " " } # ==> key1 key2

hash.each_value { |v| print v } # ==> value1value2

​

my_hash.each_value { |v| print v, " " }

# ==> 1 2 3

:symbol # symbol is like an ID in html. :Symbols != "Symbols"

# Symbols are often used as Hash keys or referencing method names.

# They can not be changed once created. They save memory (only one copy at a given time). Faster.

:test.to_s # converts to "test"

"test".to_sym # converts to :test

"test".intern # :test

# Symbols can be used like this as well:

my_hash = { key: "value", key2: "value" } # is equal to { :key => "value", :key2 => "value" }

class DerivedClass < BaseClass; end # if you want to end a Ruby statement without going to a new line, you can just type a semicolon.

​

class DerivedClass < Base

  def some_method

    super(optional args) # When you call super from inside a method, that tells Ruby to look in the superclass of the current class and find a method with the same name as the one from which super is called. If it finds it, Ruby will use the superclass' version of the method.

      # Some stuff

    end

  end

end

​

# Any given Ruby class can have only one superclass. Use mixins if you want to incorporate data or behavior from several classes into a single class.

lambda { |param| block }

multiply = lambda { |x| x * 3 }

y = [1, 2].collect(&multiply) # 3 , 6

=begin

Bla

Multyline comment

=end

# single line comment