Finding subsequence (nonconsecutive)

Question

If I have string needle and I want to check if it exists contiguously as a substring in haystack, I can use:

if needle in          


        

Answer 1

Another possibility: You can create iterators for both, needle and haystack, and then pop elements from the haystack-iterator until either all the characters in the needle are found, or the iterator is exhausted.

def is_in(needle, haystack):
    try:
        iterator = iter(haystack)
        for char in needle:
            while next(iterator) != char:
                pass
        return True
    except StopIteration:
        return False