Of course, if you're fiddling with objects which cannot be compared for equity by stringification, it is still broken.
Well, so is every uniquification based on the keys of a hash! The point still stands that grep is faster than the original idiom presented, by orders of magnitude, if still as memory-hungry.
We are the carpenters and bricklayers of the Information Age.
The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6
Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.