gistfile1.py

def remove_spans_gen(s, spans):
    checker = make_range_checker(spans); next(checker)
    return ''.join(c for (i, c) in enumerate(s) if not checker.send(i))

def make_range_checker(spans):
    idx = yield
    for (i, j) in spans:
        while idx < j:
            idx = (yield i <= idx < j)
    while True:
        yield False