[issue25898] Check for subsequence inside a sequence

Raymond Hettinger added the comment: > If I were trying to channel Raymond I'd suggest posting the > python as a recipe and see if there is uptake. However, I > could be wrong and he might be interested. (I can't say > that I've ever needed this check myself.) Yes, exactly :-)

[issue25898] Check for subsequence inside a sequence

Sebastian Linke added the comment: Slightly modified the implementation to return the index rather than a boolean. -- Added file: http://bugs.python.org/file41374/subseq_index.patch ___ Python tracker

[issue25898] Check for subsequence inside a sequence

Sebastian Linke added the comment: @Josh What is the point of using iterators here? If the user wants an iterator to be checked then he can throw that iterator right away because it was exhausted by the function. I think that in most cases the user wants to do some postprocessing on a

[issue25898] Check for subsequence inside a sequence

R. David Murray added the comment: If I were trying to channel Raymond I'd suggest posting the python as a recipe and see if there is uptake. However, I could be wrong and he might be interested. (I can't say that I've ever needed this check myself.) I'd be inclined to agree that it should

[issue25898] Check for subsequence inside a sequence

Ethan Furman added the comment: +1 for sequences +1 for subsequence_index instead of has_subsequence +1 for returning None when not found ;) -- nosy: +ethan.furman ___ Python tracker

[issue25898] Check for subsequence inside a sequence

Josh Rosenberg added the comment: Aho Corasick doesn't seem likely to be useful here; it's good if the haystack is huge (or you have many haystacks to search) and you have many needles to look for (and the needles never change), but it pays a fairly steep setup cost; for a utility that

[issue25898] Check for subsequence inside a sequence

Changes by Serhiy Storchaka : -- assignee: -> rhettinger ___ Python tracker ___ ___

[issue25898] Check for subsequence inside a sequence

Josh Rosenberg added the comment: A utility like this seems like it would belong in `itertools`, not `collections`. It should also ideally avoid fully realizing the sequence so it could work with iterators/generators as well; PySequence_Fast will force creation of a `list`/`tuple` of the

[issue25898] Check for subsequence inside a sequence

Emanuel Barry added the comment: Reviewed the Python code (unlike what my email said, it doesn't LGTM; I'm tired and just forgot). I checked the C code for the obvious pitfalls (didn't spot any), but it will require someone else better than me to look at it. -- nosy: +ebarry stage:

[issue25898] Check for subsequence inside a sequence

Марк Коренберг added the comment: Really optimal search algorithm should be something like that: https://en.wikipedia.org/wiki/Aho%E2%80%93Corasick_algorithm -- nosy: +mmarkk ___ Python tracker

[issue25898] Check for subsequence inside a sequence

New submission from Sebastian Linke: With the attached patch I propose to add a new function to the "collections" module. It is meant to be used for determining whether a given subsequence is part of a particular sequence (with respect to the ordering of the subsequence). Doing this in pure

[issue25898] Check for subsequence inside a sequence

Changes by Ethan Furman : -- nosy: +rhettinger ___ Python tracker ___ ___