sub_atom/5

Availability:built-in

[ISO]sub_atom(+Atom, ?Before, ?Len, ?After, ?Sub)

ISO predicate for breaking atoms. It maintains the following relation: Sub is a sub-atom of Atom that starts at Before, has Len characters, and Atom contains After characters after the match.

?- sub_atom(abc, 1, 1, A, S).

A = 1, S = b

The implementation minimises non-determinism and creation of atoms. This is a very flexible predicate that can do search, prefix- and suffix-matching, etc.