Question

Perl’s Data::Rmap allows you to recursively evaluate a BLOCK over a list of data structures (locally setting $_ to each element) and return the list composed of the results of such evaluations. $_ can be used to modify the elements.

This is useful for iterating over things like nested hashes, or hierarchies of arrays of hashes and the like.

Answer 1

Ruby’s Enumerable does everything you want, I think. ‘… and return the list composed of the results of such evaluations’ indicates you want Enumerable#map. My first go would be something like this:

[ {...}, {...}, {...}, ... ].map do |hash|   hash.something   do_other_stuff_with(hash)   hash                  # important to have as last line b/c of how #map works end