In case the other responses have not made it clear, this is bad code.

In addition to the convolutions that others have pointed out, note that $_ is assigned to without localizing it first. Unfortunately $_ is a global variable used by default in many places and shared across all packages. Which means that if this piece of code is in a function that is called within a for loop or a map, you will wipe out a bunch of data and not know why it happened.