Sum the content of 2 list in Groovy

Question

I have two lists in Groovy and need to sum the contents of both.

For example:

list1 = [1,1,1]
list2 = [1,1,1]

I expected this result:

total = [2,2,2]

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I try to sum with + operator o .sum method, but I have a concatenation of the lists.

[1, 1, 1, 1, 1, 1]

It's Groovy enough groovy or I need to loop each element of the lists?

Answer 1

Groovy's List.transpose() works like zip in some other languages. Try this:

list1 = [1,2,3]
list2 = [4,5,6]
assert [list1, list2].transpose()*.sum() == [5,7,9]

Answer 2

I don't know of a built-in solution, but here's a workaround using collect and the Java Queue's poll() method:

def list1 = [1, 2, 3]
def list2 = [4, 5, 6] as Queue

assert [5, 7, 9] == list1.collect { it + list2.poll() }