Determine if all elements in a list are present and in the same order in another list

Question

How do I create a function sublist() that takes two lists, list1 and list2, and returns True if list1 is a s

Answer 1

Here's an iterative solution which should have optimal asymptotics:

def sublist(x, y):
    if x and not y:
        return False
    i, lim = 0, len(y)
    for e in x:
        while e != y[i]:
            i += 1
            if i == lim:
                return False
        i += 1
    return True

@sshashank124's solution has the same complexity, but the dynamics will be somewhat different: his version traverses the second argument multiple times, but because it pushes more work into the C layer it'll probably be much faster on smaller input.

Edit: @hetman's solution has essentially the same logic, but is much more Pythonic, although, contrary to my expectation, it seems to be slightly slower. (I was also incorrect about the performance of @sshashan124's solution; the overhead of the recursive calls appears to outweigh the benefit of doing more work in C.)