SequencePosition

SequencePosition[list, sublist] gives a list of the starting and ending positions at which sublist appears in list.

SequencePosition[list, patt] gives all positions at which sequences matching patt occur in list.

SequencePosition[list, patt, n] includes only the first n occurrences.

Examples

Find positions of a sublist:

SequencePosition[{a, b, c, a, b, d}, {a, b}]
(* {{1, 2}, {4, 5}} *)

Find consecutive integer pairs:

SequencePosition[{1, 2, 4, 5, 6}, {x_, y_} /; y == x + 1]
(* {{1, 2}, {3, 4}, {4, 5}} *)

Please visit the official Wolfram Language Reference for more details.