How to compare two arrays by using perl script?

[Tsu-Fan Cheng]

Hi ALL,
   This is not a fbsd-related but a programming question. But this is
the only forum I join, I give it a try.

I have two arrays, each has two columns (so its A1, B1 and A2, B2). As
are the positions while Bs are the values. I need to get the ratio
between B1 and B2 if their As are the same or close to each other
within a certain distance. This sounds pretty straight forward but I
am not an experienced programmer. Can anybody show me how to do it by
perl? thank you!!

TFC