is there a oneline to get only the duplicatet item from an array?
i have an array like this
aTemp = [1, 1, 2, 2, 3, 4]
and i want to know, which items are duplicatet.
There are faster ways to do this, but since you asked for a one-line:
a = [1, 1, 2, 2, 3, 4]
duplicates = a.delete_if{ |x| a.grep(x).length == 1 }.uniq
#=> [1, 2]