removal of pattern from a sublist

Question

I have two lists:

 lst1 = {a,b,c,d,b,e,c}

and:

 lst2 = {b,c}

I am interested in removing all occurrences of lst2 from lst1, producing:

res = {a,d,b,e,c}

This is not exactly the same as Removing elements from a list which appear in another list; thank you for any thoughts.

lst1 //. {start___, Sequence @@ lst2, end___} :> {start, end} — Bob Hanlon, Oct 17 '16 at 00:47
What if lst1 = {a,b,a,b,a} and lst2 = {a,b,a}? Should your output be {b,a} or {a,b} or { } ? — dan7geo, Oct 17 '16 at 01:06
@dan7geo: it would be {}; thanks bob, will play around some more with it. — Suite401, Oct 17 '16 at 04:47
You need to specify in which way this question actually differs. — Yves Klett, Oct 17 '16 at 09:54

score 1 · Answer 1 · answered Oct 18 '16 at 13:00

Somehow this does not work (according to the documentation it should, or please tell me what I am doing wrong)

SequenceCases[lst1, lst2 ->{}, Overlaps -> True]

A work around would be first computing the positions to be deleted:

toBeDeleted = Flatten[Range[Sequence @@ #] & /@ SequencePosition[lst1, lst2, Overlaps -> True], 1]

And then delete these positions:

Delete[lst1, {#} & /@ toBeDeleted]

1 Answers1