That's pretty much the distinction I'd make as well, although I usually phrase it another way: for is for generic iteration, map is specifically a transformation.

A surefire way to annoy me and lose points when we get sample code is people who for whatever reason use map in void context rather than a proper for loop (it doesn't say "LOOK I R IDIOMATIC CODERZ", it says "ITERATION: UR DOIN IT WRONG" (and yes, I do have a lolcat based scale for applicants :)).

I have done some research on best practices regarding map. I wanted to ask at one point why we don't just use map instead of foreach. However I found a few nodes about that subject where, as you just did, map in a null context was brought up. However, I am not sure I understand what that means. Could you describe what map in a null context is?

-Actualize

Using map but not capturing the returned values:

map { something( $_ ) } @somelist;
[download]

In recent versions that's been optimized (basically the return values are silently discarded rather than a temporary list built and then discarded later) so it's not as blecherous performance wise.

However it really buys you nothing to use it instead of a for loop here, because you've now muddled the conceptual waters (Was it at one point using the returned values and changed? Did they plan on possibly using them at some point?) and makes the code harder to understand (rather than the important thing (what's being iterated over) being up front, you've got to read past the details (what's being done for each item) to find out). It's along the lines of using passive or active voice in a sentence ("The cow jumped over the moon." vs "The moon was jumped over by the cow"); using the wrong one can shift what the reader takes as the emphasis to the wrong part.

The cake is a lie.
The cake is a lie.
The cake is a lie.