Merge/combine two lists line by line?

Question

I have two lists stored in variables: $list1 and $list2, for example:

$list1:

a
b
c
d

$list2:

1
2
3
4

How do I merge them together line by line so that I end up with:

a1
b2
c3
d4

I have tried using array (@) but it just combines them one after the other, not line by line, example:

$list1 = @(command)
$list1 += @($list2)

Answer 1

If you prefer pipelining, you can also do it in one line:

0 .. ($list1.count -1) | ForEach-Object { $list1[$_]+$list2[$_] }