Rubyのmapとinjectのメモ

(Ruby1.9.3)

seq = ["foo", "bar"]
p seq.inject(0) { |sum, str| sum + str.length }
# >> 6

p seq.map(&:length)
# >> [3, 3]
p seq.inject(:+)
# >> "foobar"
p seq.map(&:length).inject(:+)
# >> 6

• Rubyによる関数型プログラミング