Creating an Array

Array.new                    # => [] or an empty array
Array.new(3)               # => [nil, nil, nil], an array of size 3 with no values
Array.new(5, "yay")     # => ["yay", "yay", "yay", "yay", "yay"]

# The folowing code creates a copy of an array passed in as a 
# parameter with only one instance of the default object is 
# created, this is where you can pass in a hash into an array, which
# is something you can not do with a literal

a = Array.new(2, Hash.new)
a[0]['dog'] = 'canine'
a         # => [{"dog"=>"canine"}, {"dog"=>"canine"}] 
a[1]['dog'] = 'Max'
a        # => [{"dog"=>"Max"}, {"dog"=>"Max"}]

# Creating multiple instances of a[0]['dog'] = 'canine' by using the
# curly braces {}
a = Array.new(2) { Hash.new } 
a        # => [{"dog"=>"canine"}, {}

# The last thing you can do with an array constructor is give it a 
# set size, in this case it's 5, and then calculate the element by 
# passing the element’s index to the given block and storing its return value.

squares = Array.new(5) {|i| i*i} squares # => [0, 1, 4, 9, 16]

copy = Array.new(squares) # initialized by copying squares[5] = 25
squares # => [0, 1, 4, 9, 16, 25]
copy # => [0, 1, 4, 9, 16]