Ruby LanguageDestructuring

Overview

Most of the magic of destructuring uses the splat (*) operator.

ExampleResult / comment
a, b = [0,1]a=0, b=1
a, *rest = [0,1,2,3]a=0, rest=[1,2,3]
a, * = [0,1,2,3]a=0   Equivalent to .first
*, z = [0,1,2,3]z=3   Equivalent to .last

Destructuring Block Arguments

triples = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

triples.each { |(first, second, third)| puts second }
# 2
# 5
# 8

triples.map { |(first, *rest)| rest.join(' ') } # => ["2 3", "5 6", "8 9"]