xray.open_mfdataset(paths, chunks=None, concat_dim=None, preprocess=None, engine=None, lock=None, **kwargs)

Open multiple files as a single dataset.

Experimental. Requires dask to be installed.


paths : str or sequence

Either a string glob in the form “path/to/my/files/*.nc” or an explicit list of files to open.

chunks : dict, optional

Dictionary with keys given by dimension names and values given by chunk sizes. In general, these should divide the dimensions of each dataset. By default, chunks will be chosen to load entire input files into memory at once. This has a major impact on performance: please see the full documentation for more details.

concat_dim : str or DataArray or Index, optional

Dimension to concatenate files along. This argument is passed on to xray.auto_combine() along with the dataset objects. You only need to provide this argument if the dimension along which you want to concatenate is not a dimension in the original datasets, e.g., if you want to stack a collection of 2D arrays along a third dimension.

preprocess : callable, optional

If provided, call this function on each dataset prior to concatenation.

engine : {‘netcdf4’, ‘scipy’, ‘pydap’, ‘h5netcdf’}, optional

Engine to use when reading netCDF files. If not provided, the default engine is chosen based on available dependencies, with a preference for ‘netcdf4’.

lock : False, True or threading.Lock, optional

This argument is passed on to dask.array.from_array(). By default, a per-variable lock is used when reading data from netCDF files with the netcdf4 and h5netcdf engines to avoid issues with concurrent access when using dask’s multithreaded backend.

**kwargs : optional

Additional arguments passed on to xray.open_dataset().