Array Initialization: Difference between revisions

=={{header|Ruby}}==

{{trans|Python}}

Ruby exhibits from some the same symptoms of references to objects as the Python solution

<lang ruby>a = ['an', 'apple', 'a', 'day', '...']

b = %w(an apple a day ...)

a == b # => true

width, height = 3, 2

a = [0] * width # OK => [0, 0, 0]

a[0] = 1

a # => [1, 0, 0]

a = [[0] * width] * height # => [[0, 0, 0], [0, 0, 0]]

a[0][0] = 1

a # => [[1, 0, 0], [1, 0, 0]] -- oops

a[0] == a[1] # => true -- as we expect

a[0].equal? a[1] # => true -- oops, same object

a = Array.new(height) { Array.new(width) {0} } # => [[0, 0, 0], [0, 0, 0]]

a[0].equal? a[1] # => false -- phew!

a[0][0] = 1

a # => [[1, 0, 0], [0, 0, 0]] -- OK</lang>