map -package:containers -package:foldl -package:insert-ordered-containers -package:invertible -package:charset -package:base-compat -package:conduit is:exact package:base-prelude

map f xs is the list obtained by applying f to each element of xs, i.e.,
map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn]
map f [x1, x2, ...] == [f x1, f x2, ...]
>>> map (+1) [1, 2, 3]
[2,3,4]