python – How to read pickle file?

python – How to read pickle file?

Pickle serializes a single object at a time, and reads back a single object –
the pickled data is recorded in sequence on the file.

If you simply do pickle.load you should be reading the first object serialized into the file (not the last one as youve written).

After unserializing the first object, the file-pointer is at the beggining
of the next object – if you simply call pickle.load again, it will read that next object – do that until the end of the file.

objects = []
with (open(myfile, rb)) as openfile:
    while True:
        try:
            objects.append(pickle.load(openfile))
        except EOFError:
            break

There is a read_pickle function as part of pandas 0.22+

import pandas as pd

object = pd.read_pickle(rfilepath)

python – How to read pickle file?

The following is an example of how you might write and read a pickle file. Note that if you keep appending pickle data to the file, you will need to continue reading from the file until you find what you want or an exception is generated by reaching the end of the file. That is what the last function does.

import os
import pickle


PICKLE_FILE = pickle.dat


def main():
    # append data to the pickle file
    add_to_pickle(PICKLE_FILE, 123)
    add_to_pickle(PICKLE_FILE, Hello)
    add_to_pickle(PICKLE_FILE, None)
    add_to_pickle(PICKLE_FILE, bWorld)
    add_to_pickle(PICKLE_FILE, 456.789)
    # load & show all stored objects
    for item in read_from_pickle(PICKLE_FILE):
        print(repr(item))
    os.remove(PICKLE_FILE)


def add_to_pickle(path, item):
    with open(path, ab) as file:
        pickle.dump(item, file, pickle.HIGHEST_PROTOCOL)


def read_from_pickle(path):
    with open(path, rb) as file:
        try:
            while True:
                yield pickle.load(file)
        except EOFError:
            pass


if __name__ == __main__:
    main()