Ruby Quicktips

Select from a Hash by value

Say, we have a Hash with codes for colors:

COLOR = { :red => 1, :white => 2, :black => 3, :yellow => 4 }

…and we want to check which color belongs to number 3.

COLOR.invert[3]
#=> :black

This tip uses Hash#invert, which “returns a new hash, created by using hsh‘s values as keys, and the keys as values.”