Source code for astropy.io.misc.pickle_helpers

# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""
This module contains simple input/output related functionality that is not
part of a larger framework or standard.
"""

import pickle

__all__ = ['fnpickle', 'fnunpickle']


[docs]def fnunpickle(fileorname, number=0): """ Unpickle pickled objects from a specified file and return the contents. Parameters ---------- fileorname : str or file-like The file name or file from which to unpickle objects. If a file object, it should have been opened in binary mode. number : int If 0, a single object will be returned (the first in the file). If >0, this specifies the number of objects to be unpickled, and a list will be returned with exactly that many objects. If <0, all objects in the file will be unpickled and returned as a list. Raises ------ EOFError If ``number`` is >0 and there are fewer than ``number`` objects in the pickled file. Returns ------- contents : object or list If ``number`` is 0, this is a individual object - the first one unpickled from the file. Otherwise, it is a list of objects unpickled from the file. """ if isinstance(fileorname, str): f = open(fileorname, 'rb') close = True else: f = fileorname close = False try: if number > 0: # get that number res = [] for i in range(number): res.append(pickle.load(f)) elif number < 0: # get all objects res = [] eof = False while not eof: try: res.append(pickle.load(f)) except EOFError: eof = True else: # number==0 res = pickle.load(f) finally: if close: f.close() return res
[docs]def fnpickle(object, fileorname, protocol=None, append=False): """Pickle an object to a specified file. Parameters ---------- object The python object to pickle. fileorname : str or file-like The filename or file into which the `object` should be pickled. If a file object, it should have been opened in binary mode. protocol : int or None Pickle protocol to use - see the :mod:`pickle` module for details on these options. If None, the most recent protocol will be used. append : bool If True, the object is appended to the end of the file, otherwise the file will be overwritten (if a file object is given instead of a file name, this has no effect). """ if protocol is None: protocol = pickle.HIGHEST_PROTOCOL if isinstance(fileorname, str): f = open(fileorname, 'ab' if append else 'wb') close = True else: f = fileorname close = False try: pickle.dump(object, f, protocol=protocol) finally: if close: f.close()