... for big lists ...
I agree about the time/space advantages, sometimes life-saving advantages, of in-place mutation for big lists.
... postfix for ... generate[s] a list as big as the array.
I thought a for-loop, postfix or otherwise, was guaranteed to have a space complexity (if that's the correct term) of zero | 1 (per ikegami here) — if it's written right! That, e.g., either
for (@humongous_array) { $_ = $_ + $_ }
or
$_ = $_ + $_ for @humongous_array;
are guaranteed to be just fine (if @humongous_array could fit in memory in the first place), whereas
@humongous_array = map $_ + $_, @humongous_array;
can kill you in terms of both time and space. In fact, isn't it the case that beginning with Perl version 5.mumble, map called in void context produces no intermediate list/array, so even
map $_ = $_ + $_, @humongous_array;
should be perfectly safe (although for aesthetic reasons, I'm not a fan of this particular usage)?
And let's just not talk about Fight Club | grep anymore.
Give a man a fish: <%-{-{-{-<
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