cleanest way to call one function on a list of items
The change from map() (and many other functions from 2.7 to 3.x) returning a generator instead of a list is a memory saving technique. For most cases, there is no performance penalty to writing out the loop more formally (it may even be preferred for readability).
I would provide an example, but @vaultah nailed it in the comments: still a one-liner:
for x in glob.glob("*.pyc"): os.remove(x)