Function groupby_defaultdict

xarray/structure/combine.py:727–736

replacement for itertools.groupby

(
    iter: list[T],
    key: Callable[[T], K],
)

def groupby_defaultdict(
    iter: list[T],
    key: Callable[[T], K],
) -> Iterator[tuple[K, Iterator[T]]]:
    """replacement for itertools.groupby"""
    idx = defaultdict(list)
    for i, obj in enumerate(iter):
        idx[key(obj)].append(i)
    for k, ix in idx.items():
        yield k, (iter[i] for i in ix)


def _combine_single_variable_hypercube(