Question

Input >> list = [[1,2,3], [6], [3,4,5,6]]

Output >> [1,2,3,3,4,5,6,6] 

I want to know if there is something more straightforward than this

l = []
list.each{ l = l + it }
println l

like a default groovy closure or method?

Answer 1

Try flatten, ie:

list.flatten()

Or, to get the output you want:

list = [[1,2,3], [6], [3,4,5,6]]

assert list.flatten().sort() == [1,2,3,3,4,5,6,6]