Zip function that requires the same lengths (and still works with generators).

zip_strict.py

def zip_strict(*args):
    """Same as zip(), but raises a ValueError if the lengths don't match."""
    iters = [iter(axis) for axis in args]
    n_elements = 0
    failures = []
    while len(failures) == 0:
        n_elements += 1
        values = []
        failures = []
        for axis, iterator in enumerate(iters):
            try:
                values.append(next(iterator))
            except StopIteration:
                failures.append(axis)
        if len(failures) == 0:
            yield tuple(values)
    if len(failures) == 1:
        raise ValueError("Too few elements ({}) along axis {}".format(n_elements, failures[0]))
    elif len(failures) < len(iters):
        raise ValueError("Too few elements ({}) along axes {}".format(n_elements, failures))