Behaviour of Array bang methods

Question

Some bang version of Array methods are like compact!, reject!, flatten!, uniq! return nil if no

Answer 1

The bang (!) methods do modify the current object in place, but they do return nil if there are no affected elements per the documentation. This is useful if, for whatever reason, you need to do something if you did modify the array in question.

if array.flatten!
  puts "Oh yeah... flattened that array!"
end