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NPYInputOutput#

class pybrops.core.io.NPYInputOutput.NPYInputOutput[source]#

Bases: object

Abstract class for defining .npy file input/output functionality.

This abstract class defines two functions with the following purposes:

  • to_npy - write an object to a .npy file.

  • from_npy - load an object from a .npy file.

Methods

from_npy

Read an object from a .npy file(s).

to_npy

Write an object to a .npy file.
abstract classmethod from_npy(filename, fieldname, mmap_mode, allow_pickle, fix_imports, encoding, max_header_size, **kwargs)[source]#

Read an object from a .npy file(s).

Parameters:

  • filename (str, Sequence of str) – .npy file name(s) from which to load field(s).

  • fieldname (str, Sequence of str) – Name(s) of field(s) within the object for which to load.

  • mmap_mode (str, None, default = None) – Options are {None, "r+", "r", "w+", "c"} If not None, then memory-map the file, using the given mode (see numpy.memmap for a detailed description of the modes). A memory-mapped array is kept on disk. However, it can be accessed and sliced like any ndarray. Memory mapping is especially useful for accessing small fragments of large files without reading the entire file into memory. Default: None

  • allow_pickle (bool, default = False) – Allow loading pickled object arrays stored in .npy files. Reasons for disallowing pickles include security, as loading pickled data can execute arbitrary code. If pickles are disallowed, loading object arrays will fail. Default: False

  • fix_imports (bool, default = True) – Only useful when loading Python 2 generated pickled files on Python 3, which includes .npy/.npz files containing object arrays. If fix_imports is True, pickle will try to map the old Python 2 names to the new names used in Python 3. Default: True

  • encoding (str, default = "ASCII") – What encoding to use when reading Python 2 strings. Only useful when loading Python 2 generated pickled files in Python 3, which includes .npy/.npz files containing object arrays. Values other than "latin1", "ASCII", and "bytes" are not allowed, as they can corrupt numerical data. Default: "ASCII"

  • max_header_size (int, optional) – Maximum allowed size of the header. Large headers may not be safe to load securely and thus require explicitly passing a larger value. See ast.literal_eval for details. This option is ignored when allow_pickle is passed. In that case the file is by definition trusted and the limit is unnecessary. Default: 10000

  • kwargs (dict) – Additional keyword arguments to use for dictating importing from a .npy file(s).

Returns:

out – An object read from a .npy file(s).

Return type:

NPYInputOutput

abstract to_npy(filename, fieldname, allow_pickle, fix_imports, **kwargs)[source]#

Write an object to a .npy file.

Parameters:

  • filename (str, Sequence of str) – .npy file name(s) to which to write field(s).

  • fieldname (str, Sequence of str) – Name(s) of field(s) within the object for which to save.

  • allow_pickle (bool, default = True) – Allow saving object arrays using Python pickles. Reasons for disallowing pickles include security (loading pickled data can execute arbitrary code) and portability (pickled objects may not be loadable on different Python installations, for example if the stored objects require libraries that are not available, and not all pickled data is compatible between Python 2 and Python 3). Default: True

  • fix_imports (bool, default = True) – Only useful in forcing objects in object arrays on Python 3 to be pickled in a Python 2 compatible way. If fix_imports is True, pickle will try to map the new Python 3 names to the old module names used in Python 2, so that the pickle data stream is readable with Python 2. Default: True

  • kwargs (dict) – Additional keyword arguments to use for dictating export to a .npy file.

Return type:

None

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