Function _parse_datasets

xarray/structure/concat.py:563–602

(
    datasets: list[T_Dataset],
)

# determine dimensional coordinate names and a dict mapping name to DataArray
def _parse_datasets(
    datasets: list[T_Dataset],
) -> tuple[
    set[Hashable],
    dict[Hashable, Variable],
    dict[Hashable, int],
    set[Hashable],
    set[Hashable],
    list[Hashable],
]:
    dims: set[Hashable] = set()
    all_coord_names: set[Hashable] = set()
    data_vars: set[Hashable] = set()  # list of data_vars
    dim_coords: dict[Hashable, Variable] = {}  # maps dim name to variable
    dims_sizes: dict[Hashable, int] = {}  # shared dimension sizes to expand variables
    variables_order: dict[Hashable, Variable] = {}  # variables in order of appearance

    for ds in datasets:
        dims_sizes.update(ds.sizes)
        all_coord_names.update(ds.coords)
        data_vars.update(ds.data_vars)
        variables_order.update(ds.variables)

        # preserves ordering of dimensions
        for dim in ds.dims:
            if dim in dims:
                continue

            if dim in ds.coords and dim not in dim_coords:
                dim_coords[dim] = ds.coords[dim].variable
        dims = dims | set(ds.dims)

    return (
        dims,
        dim_coords,
        dims_sizes,
        all_coord_names,
        data_vars,
        list(variables_order),
    )


def _dataset_concat(