A generalization of fmap, mapWithIndex takes a mapping
function that also depends on the element's index, and applies it to
every element in the sequence.
A generalization of fmap, mapWithIndex takes a mapping
function that also depends on the element's index, and applies it to
every element in the sequence.
O(n). A generalization of foldMap1,
foldMapWithIndex takes a folding function that also depends on
the element's index, and applies it to every element in the sequence.