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SequenceCases

Find matching subsequences in a list.

$ wo 'SequenceCases[x, y]'

SequenceCases::list: List expected at position 1 in SequenceCases[x, y].
SequenceCases[x, y]

The Overlaps option controls how much of the list a match may share with its neighbours. The default keeps matches disjoint, Overlaps -> True reports the longest match at every start position, and Overlaps -> All reports every match at every start position:

$ wo 'SequenceCases[{1, 2, 3}, {__}]'
{{1, 2, 3}}

$ wo 'SequenceCases[{1, 2, 3}, {__}, Overlaps -> True]'
{{1, 2, 3}, {2, 3}, {3}}

$ wo 'SequenceCases[{1, 2, 3}, {__}, Overlaps -> All]'
{{1, 2, 3}, {1, 2}, {1}, {2, 3}, {2}, {3}}

The name : pattern :> body binding form lets the right-hand side reference the matched sub-list:

$ wo 'SequenceCases[{1/2, 1/3, 1/16}, l : {_, 1 ...} :> Length[l]]'
{1, 1, 1}