Advice? I prefer my first version for when I come back later.

Not sure whether you want opinions on what other people would find preferable, or what we think that you should use.  In case of the latter, I think you've already answered the question yourself. If you find the procedural version easier to understand, then by all means stick with it — unless maybe you're anticipating that some potential future maintainer is going to have less difficulties with the functional variant.

Personally, I think the functional style sometimes allows to express things more compactly (and thus it's less/easier to parse for those familiar with the style), but there's no point in using map and grep just for the sake of using them...