hi all,

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.

i thought i can do it like
aTemp - aTemp.uniq

[1, 1, 2, 2, 3, 4] - [1, 2, 3, 4] => [1, 2]
like inside the manual

but i get only an empty array


so i found an bad solution and hope you can help me to get the right way.

thanks for your help
nico