From the docs:

split

Splits a string into a list of strings and returns that list. By default, empty leading fields are preserved, and empty trailing ones are deleted.

In scalar context, returns the number of fields found and splits into the @_ array. Use of split in scalar context is deprecated, however, because it clobbers your subroutine arguments.

CountZero

"If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law