Hashes

Hashes can also be initialized in a number of ways:

h1 = {} # empty hash h2 = Hash.new # same as h1 h3 = {"dog" => "bark", "cat" => "meow"} h4 = Hash["dog" => "bark", "cat" => "meow"] # same as h3 h5 = Hash.new(0) # set default value to 0

Hashes are accessed with square brackets, just like arrays:

h3["dog"] => "bark" h3["cat"] => "meow" h3["cow"] => nil

And hashes have lots of useful methods:

h3.keys => ["cat", "dog"] h3.values => ["meow", "dog"] h3.length => 2