Ruby Reference by Examples

rubyref.rb

module MyModule
  def module_method
  end
end

class RubyRef < BaseClass
  include MyModule
  attr_reader :a
  attr_writer :b
  attr_accessor :c
  
  def initialize(a, b, c)
    @a = a
  end

  def numeric_literals
    n = 123 + 1_000_000 + -5000 + 0777 + 0x0d + 0v1010101 + ?b + ?\n  
    n = 123456789012345235235
    n = 1234.4 + 1.02e23 + 4E20 + 4e+20
  end
  
  def string_literals
    ['no interp', %q(no interp), "yo #{var}", %Q(interp "#tvxpression}"), %Q(intern)]
    `command hello` || %x(command hello)
    print <<"EOS"   # "EOS" or 'EOS' or `EOS`
      blah
EOS
  end
  
  def control_structures
    if true
      true
    elsif false
      false
    else
      nil
    end
    something() if true
    something() unless  false
    
  end
  
  def loops
    loop do
      break if done
    end
    
    while true
      something
    end
    
    until true
      something
    end
    
    begin
      something
    end while true
    
    for var in expression
      p var
    end
    
    
  
  def arrays
    a = ['hi', 123, Time.new] + %w(nointerp words) + %W(interp a#{Time.new}z)
    a[0] == a.first
    a.size
    a.reverse
    a.sort {|a,b| a<=>b}
  end

  def hashes
    h = {"key" => "value", symbol:123}
    h["key"]
    h.fetch("key") {|missing| missing.object_id }
    h = Hash[ [a:, 1, :b, 2].collect { |v|
    h = arr.each_with_object({}) { |v,h| h[v] = f(v) }
    h = Hash[arr.collect { |v| [v, f(v)] }]
    h = Hash[arr.zip(arr.map(&method(:f)))]
  end

  def enumerate_arrays_and_hashes
    a.each { |element| puts element }
    a.each_with_index { |element, index| puts element * index }
    a.find_all {|e| e.even? }
    a.grep(/regex/) {|match| match.upcase} # optional block
    a.inject(initial) {|memo, element| memo + element}
    total = [1,2,3].inject(&:+)
    a.map {|e| e * 2 }
    a.max - a.min {|a,b| a <=> b }
  end
  
  def ranges
    (1..9) == (1...10)
    (1..10).each { |i| puts i }
  end
  
  def exceptions
    begin
      raise Exception, "message"
    rescue Exception => var
      puts var
    else
      puts "completed without exception"
    ensure
      puts "always executed"
    end
  end
  
  def files
    puts File.read("filename")
    File.open(filename, "r") { |f| f.gets }
    IO.foreach(path) {|line| puts line }
    array = IO.readlines(path)
  end
  
  def blocks
    
end