how to get coll to put the index number of matching value

hi all! i can't seem to figure out how to do what i'm trying to do.

let's say i have a coll, with 8 lists, indexed from 1 through 8, each of which contains either a 0 or a 1.

what i'd like to be able to do, is to tell coll to output the index of every list containing "1", so let's say my coll is

1 0
2 1
3 0
4 0
5 1
6 0
7 0
8 1

i'd like to be able to bang out a list which reads "2, 5, 8"

how would i go about doing that?