Split a list into multiple ones

Question

I am trying to split a list into multiple ones. The original list lst should be split on every element that is present in a second list, split_on.

Example:

lst = [1, 2, 3, 4, 5, 6, 7, 8]
split_on = [3, 4, 7]

should yield:

[[1,2,3],[3,4],[4,5,6,7],[7,8]]

Note that both lst and split_on do not contain duplicate elements and that any item of split_on is also an item of lst. Finally, the order of the elements of split_on can be random.

Answer 1

How about the following:

a = [1,2,3,4,5,6,7,8]
b = [4,3,7]

res = [[]]
for i in a:
    res[-1].append(i)
    if i in b:
        res.append([i])

print(res)  # [[1, 2, 3], [3, 4], [4, 5, 6, 7], [7, 8]]

Note that since b is only used for membership tests and the order does not matter, you could consider converting it to a set so that the approach scales better.