I have two lists of data that I want to compare to see if there are
any common entries. should I do this using a vlookup or matching
function? or other?

as below, the data is formatted differently in each list- this first
list is a combination of 7 and 10 digit codes, the second has both the
7 and 10 digit code for each entry:

List 1
aaaaaaa
bbbbbbbbbb
cccccccccc
ddddddd
..
..
..
..


List 2
xxxxxxx xxxxxxxxxx
yyyyyyy yyyyyyyyyy
zzzzzzz zzzzzzzzzz
..
..
..
..

thanks for your help!