Remove the first N items that match a condition in a Python list

Question

If I have a function matchCondition(x), how can I remove the first n items in a Python list that match that condition?

One solution is to itera

Answer 1

The accepted answer was a little too magical for my liking. Here's one where the flow is hopefully a bit clearer to follow:

def matchCondition(x):
    return x < 5


def my_gen(L, drop_condition, max_drops=3):
    count = 0
    iterator = iter(L)
    for element in iterator:
        if drop_condition(element):
            count += 1
            if count >= max_drops:
                break
        else:
            yield element
    yield from iterator


example = [1, 10, 2, 9, 3, 8, 4, 7]

print(list(my_gen(example, drop_condition=matchCondition)))

It's similar to logic in davidism answer, but instead of checking the drop count is exceeded on every step, we just short-circuit the rest of the loop.

Note: If you don't have yield from available, just replace it with another for loop over the remaining items in iterator.