exists

Lib.exists : ('a -> bool) -> 'a list -> bool

Check if a predicate holds somewhere in a list.

An invocation exists P l returns true if P holds of some element of l. Since there are no elements of [], exists P [] always returns false.

Failure

When searching for an element of l that P holds of, it may happen that an application of P to an element of l raises an exception. In that case, exists P l raises an exception.

Example

- exists (fn i => i mod 2 = 0) [1,3,4];
> val it = true : bool

- exists (fn _ => raise Fail "") [];
> val it = false : bool

- exists (fn _ => raise Fail "") [1];
! Uncaught exception:
! Fail  ""

See also

Lib.all, Lib.first, Lib.tryfind