Ruby has a lot of great idiomatic ways to doing common things. The problem is a lot of them seem reminiscent of crazy perl magic when you first see them… One of the nicest ones is the & or to_proc concept
['this','is','a','collection'].each do |element|
element.capitalize!
end
#['This','Is','A','Collection']OK so thats already a nice easy way of doing things. Its clear and concise, however in Ruby there is an even easier way
['this','is','a','collection'].map(&:capitalize)
#['This','Is','A','Collection']Even less code ! But a bit more confusing… Whats going on here?
Well & is Ruby’s to-proc operator meaning it converts a block to a proc. In this case it is used to create a lambda/proc for the map method and therefore apply String#capitalize to each element of the array.
The argument to this operator is the symbol of the method String#capitalize i.e. :capitalize