Partitioning and Splitting

proplists:split/2

Partitions a proplist into sublists based on specified keys:

lfe> (proplists:split 
      '((c 2) (e 1) a (c 3 4) d (b 5) b)
      '(a b c))
(((a) ((b 5) b) ((c 2) (c 3 4))) ((e 1) d))

The result is a tuple {Lists, Rest} where Lists contains one sublist for each key (in the order specified), and Rest contains everything else. Relative order is preserved within each sublist, which means this operation is stable and predictable—rare qualities in a chaotic universe.