cf.GatheredArray

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class cf.GatheredArray(compressed_array=None, shape=None, size=None, ndim=None, compressed_dimension=None, compressed_dimensions=None, list_variable=None, source=None, copy=True)

Bases: cf.data.array.mixin.compressedarraymixin.CompressedArrayMixin, cf.data.array.mixin.arraymixin.ArrayMixin, cf.mixin_container.Container, cfdm.data.gatheredarray.GatheredArray

An underlying gathered array.

Compression by gathering combines axes of a multidimensional array into a new, discrete axis whilst omitting the missing values and thus reducing the number of values that need to be stored.

The information needed to uncompress the data is stored in a “list variable” that gives the indices of the required points.

See CF section 8.2. “Lossless Compression by Gathering”.

New in version 3.0.0.

Initialisation

Parameters

compressed_array: array_like

The compressed array.

shape: tuple

The shape of the uncompressed array.

compressed_dimensions: dict

Mapping of compressed to uncompressed dimensions.

A dictionary key is a position of a dimension in the compressed data, with a value of the positions of the corresponding dimensions in the uncompressed data. Compressed array dimensions that are not compressed must be omitted from the mapping.

Parameter example:

{2: (2, 3)}

New in version (cfdm): 1.10.0.0

list_variable: List

The “list variable” required to uncompress the data, identical to the data of a CF-netCDF list variable.

compressed_dimension: deprecated at version 1.10.0.0

Use the compressed_dimensions parameter instead.

source: optional

Convert source, which can be any type of object, to a GatheredArray instance.

All other parameters, apart from copy, are ignored and their values are instead inferred from source by assuming that it has the GatheredArray API. Any parameters that can not be retrieved from source in this way are assumed to have their default value.

Note that if x is also a GatheredArray instance then cf.GatheredArray(source=x) is equivalent to x.copy().

New in version (cfdm): 1.10.0.0

copy: bool, optional

If True (the default) then deep copy the input parameters prior to initialisation. By default the parameters are not deep copied.

New in version (cfdm): 1.10.0.0

size: int

Deprecated at version 1.10.0.0. Ignored if set.

Number of elements in the uncompressed array.

ndim: int

Deprecated at version 1.10.0.0. Ignored if set.

The number of uncompressed array dimensions

Methods

compressed_dimensions	Mapping of compressed to uncompressed dimensions.
conformed_data	The compressed data and list variable.
copy	Return a deep copy of the array.
get_calendar	The calendar of the array.
get_compressed_axes	Return axes that are compressed in the underlying array.
get_compressed_dimension	Returns the compressed dimension’s position in the array.
get_compression_type	Returns the array’s compression type.
cf.GatheredArray.get_filename'
get_filenames	Return the names of any files containing the compressed data.
get_list	Return the list variable for a compressed array.
get_Subarray	Return the Subarray class.
get_subspace	Return a subspace, defined by indices, of a numpy array.
get_units	The units of the array.
source	Return the underlying array object.
subarray_shapes	Create the subarray shapes along each uncompressed dimension.
subarrays	Return descriptors for every subarray.
subarray_parameters	Non-data parameters required by the Subarray class.
to_dask_array	Convert the data to a dask array.
to_memory	Bring data on disk into memory.

Attributes

array	Returns a numpy array containing the uncompressed data.
compressed_array	Returns an independent numpy array with the compressed data.
dtype	The data-type of the uncompressed data.
ndim	Number of array dimensions.
shape	Shape of the uncompressed data.
size	Number of elements in the array.
Units	The cf.Units object containing the units of the array.