Ruby Tricks 2

1. Integer#digits

123.to_s.chars.map(&:to_i).reverse

=> [3, 2, 1]

123.digits

=> [3,2,1]

2. Array#values_at

arr = [1,2,3,4,5]

a, b, c = arr[0], arr[1], arr[4]


a, b, c = arr.values_at(0, 1, 4)

hash = {bacon: 300, chocolate: 200}

hash.values_at(:bacon, :chocolate)


=> [300, 200]

3. Hash#transform_values

h = {bacon: 200, coconut: 300}

h.each { |k,v| h[k] = v*2 }
h.transform_values! { |v| v * 2 }
{:bacon=>400, :coconut=>600}

4. Array#count

letters = %w(a a a b c d a)

letters.count("a")

=> 4
numbers = [1,2,3,4,5,6]

numbers.count(&:even?)

=> 3