cf.Data.get_filenames

Data.get_filenames()[source]

The names of files containing parts of the data array.

Returns the names of any files that may be required to deliver the computed data array. This set may contain fewer names than the collection of file names that defined the data when it was first instantiated, as could be the case after the data has been subspaced.

Implementation

A dask chunk that contributes to the computed array is assumed to reference data within a file if that chunk’s array object has a callable get_filenames method, the output of which is added to the returned set.

Returns
set

The file names. If no files are required to compute the data then an empty set is returned.

Examples

>>> d = cf.Data.full((5, 8), 1, chunks=4)
>>> d.get_filenames()
set()

>>> f = cf.example_field(0)
>>> cf.write(f, "file_A.nc")
>>> cf.write(f, "file_B.nc")

>>> a = cf.read("file_A.nc", chunks=4)[0].data
>>> a += 999
>>> b = cf.read("file_B.nc", chunks=4)[0].data
>>> c = cf.Data(b.array, units=b.Units, chunks=4)
>>> print(a.shape, b.shape, c.shape)
(5, 8) (5, 8) (5, 8)
>>> d = cf.Data.concatenate([a, a.copy(), b, c], axis=1)
>>> print(d.shape)
(5, 32)

>>> d.get_filenames()
{'file_A.nc', 'file_B.nc'}
>>> d[:, 2:7].get_filenames()
{'file_A.nc'}
>>> d[:, 2:14].get_filenames()
{'file_A.nc', 'file_B.nc'}
>>> d[:, 2:20].get_filenames()
{'file_A.nc', 'file_B.nc'}
>>> d[:, 2:30].get_filenames()
{'file_A.nc', 'file_B.nc'}
>>> d[:, 29:30].get_filenames()
set()
>>> d[2, 3] = -99
>>> d[2, 3].get_filenames()
{'file_A.nc'}