http://www.perlmonks.org?node_id=988657


in reply to given and for

First of all for and given are not equivalent, they differ subtly in the scoping of their $_ variable:

use strict; use warnings; use 5.010; $_ = 42; sub f { say } given (23) { f } for (23) { f } __END__ 42 23

So given creates a new lexical $_, while for localizes the existing $_, which results in dynamic scoping.

But the real reason is that code must be readable to humans, and for has the connotation of a loop, whereas given makes it implicit that it's one value that is talked about. So it's all about intent.