I was reading about collect method here http://apidock.com/ruby/Array/collect and I find this example:
>> ['a', 'b', 'c'].collect(&:capitalize)
=> ["A", "B", "C"]
Where it is short and nice way of:
>> ['a', 'b', 'c'].collect{|letter| letter.capitalize}
=> ["A", "B", "C"]
What does &:
means in the first line???