How to test if one string is a subsequence of another? [duplicate]

Answer 1

I was trying to understand falsetru's solution, and essentially using iter simplifies what the following would be doing:

def is_subseq(sub, string):
    i = 0
    for c in string:
        if i == len(sub):
            break
        if sub[i] == c:
            i += 1
    if i != len(sub):
        return False
    return True


def is_subseq2(sub, string):
    j = 0
    count = 0
    for c in sub:
        if j == len(string):
            return False
        while j < len(string) and string[j] != c:
            j += 1
        if string[j] == c:
            count += 1
    return count == len(sub)