Function open_mfdataset

xarray/backends/api.py:1373–1708

Open multiple files as a single dataset. If combine='by_coords' then the function ``combine_by_coords`` is used to combine the datasets into one before returning the result, and if combine='nested' then ``combine_nested`` is used. The filepaths must be structured according to which

(
    paths: (
        str | os.PathLike | ReadBuffer | NestedSequence[str | os.PathLike | ReadBuffer]
    ),
    chunks: T_Chunks = None,
    concat_dim: (
        str
        | DataArray
        | Index
        | Sequence[str]
        | Sequence[DataArray]
        | Sequence[Index]
        | None
    ) = None,
    compat: CompatOptions | CombineKwargDefault = _COMPAT_DEFAULT,
    preprocess: Callable[[Dataset], Dataset] | None = None,
    engine: T_Engine = None,
    data_vars: (
        Literal["all", "minimal", "different"] | None | list[str] | CombineKwargDefault
    ) = _DATA_VARS_DEFAULT,
    coords=_COORDS_DEFAULT,
    combine: Literal["by_coords", "nested"] = "by_coords",
    parallel: bool = False,
    join: JoinOptions | CombineKwargDefault = _JOIN_DEFAULT,
    attrs_file: str | os.PathLike | None = None,
    combine_attrs: CombineAttrsOptions = "override",
    errors: ErrorOptionsWithWarn = "raise",
    **kwargs,
)

def open_mfdataset(
    paths: (
        str | os.PathLike | ReadBuffer | NestedSequence[str | os.PathLike | ReadBuffer]
    ),
    chunks: T_Chunks = None,
    concat_dim: (
        str
        | DataArray
        | Index
        | Sequence[str]
        | Sequence[DataArray]
        | Sequence[Index]
        | None
    ) = None,
    compat: CompatOptions | CombineKwargDefault = _COMPAT_DEFAULT,
    preprocess: Callable[[Dataset], Dataset] | None = None,
    engine: T_Engine = None,
    data_vars: (
        Literal["all", "minimal", "different"] | None | list[str] | CombineKwargDefault
    ) = _DATA_VARS_DEFAULT,
    coords=_COORDS_DEFAULT,
    combine: Literal["by_coords", "nested"] = "by_coords",
    parallel: bool = False,
    join: JoinOptions | CombineKwargDefault = _JOIN_DEFAULT,
    attrs_file: str | os.PathLike | None = None,
    combine_attrs: CombineAttrsOptions = "override",
    errors: ErrorOptionsWithWarn = "raise",
    **kwargs,
) -> Dataset:
    """Open multiple files as a single dataset.

    If combine='by_coords' then the function ``combine_by_coords`` is used to combine
    the datasets into one before returning the result, and if combine='nested' then
    ``combine_nested`` is used. The filepaths must be structured according to which
    combining function is used, the details of which are given in the documentation for
    ``combine_by_coords`` and ``combine_nested``. By default ``combine='by_coords'``
    will be used. Requires dask to be installed. See documentation for
    details on dask [1]_. Global attributes from the ``attrs_file`` are used
    for the combined dataset.

    Parameters
    ----------
    paths : str or nested sequence of paths
        Either a string glob in the form ``"path/to/my/files/*.nc"`` or an explicit list of
        files to open. Paths can be given as strings or as pathlib Paths. If
        concatenation along more than one dimension is desired, then ``paths`` must be a
        nested list-of-lists (see ``combine_nested`` for details). (A string glob will
        be expanded to a 1-dimensional list.)
    chunks : int, dict, 'auto' or None, optional
        Dictionary with keys given by dimension names and values given by chunk sizes.
        In general, these should divide the dimensions of each dataset. If int, chunk
        each dimension by ``chunks``. By default, chunks will be chosen to match the
        chunks on disk. This may impact performance: please see the full documentation
        for more details [2]_. This argument is evaluated on a per-file basis, so chunk
        sizes that span multiple files will be ignored.
    concat_dim : str, DataArray, Index or a Sequence of these or None, optional
        Dimensions to concatenate files along.  You only need to provide this argument
        if ``combine='nested'``, and if any of the dimensions along which you want to