partitionLib.partition : ('a -> bool) -> 'a list -> 'a list * 'a listSplit a list by a predicate.
An invocation partition P l divides l into
a pair of lists (l1,l2). P holds of each
element of l1, and P does not hold of any
element of l2.
If applying P to any element of l results
in failure.
> partition (fn i => i mod 2 = 0) [1,2,3,4,5,6,7,8,9];
val it = ([2, 4, 6, 8], [1, 3, 5, 7, 9]): int list * int list
> partition (fn _ => true) [1,2,3];
val it = ([1, 2, 3], []): int list * int list
> partition (fn _ => raise Fail "") ([]:int list);
val it = ([], []): int list * int list
> partition (fn _ => raise Fail "") [1];
Exception- Fail "" raised