Load all pickled objects [duplicate]

问题

import pickle

ListNames = [["Name1","City1","Email1"],["Name2","City2","Number2"]]
ListNumbers = [1,2,3,4,5,6,7,8]

with open ("TestPickle.pickle","wb") as fileSaver:
    pickle.dump(ListNames,fileSaver)
    pickle.dump(ListNumbers,fileSaver)

with open ("TestPickle.pickle","rb") as fileOpener:
    print(pickle.load(fileOpener))

The output is:

[['Name1', 'City1', 'Email1'], ['Name2', 'City2', 'Number2']]

How do I get pickle to load the ListNumbers too

I know I can just print pickle.load again but what if I have an unknown number of items in my pickle file with a number of Datatypes (e.g: lists, tuples, dictionaries, strings....)

Thanks

回答1:

I am not sure if this i the correct approach.

import pickle

ListNames = [["Name1","City1","Email1"],["Name2","City2","Number2"]]
ListNumbers = [1,2,3,4,5,6,7,8]

with open ("TestPickle.pickle","wb") as fileSaver:
    pickle.dump(ListNames,fileSaver)
    pickle.dump(ListNumbers,fileSaver)
obj = []
with open("TestPickle.pickle","rb") as fileOpener:
    while True:
        try:
            obj.append(pickle.load(fileOpener))
        except EOFError:
            break
print obj

Output:

[[['Name1', 'City1', 'Email1'], ['Name2', 'City2', 'Number2']], [1, 2, 3, 4, 5, 6, 7, 8]]

回答2:

I know I can just print pickle.load again but what if I have an unknown number of items in my pickle file with a number of Datatypes (e.g: lists, tuples, dictionaries, strings....)

There are several ways around this:

Pack all of the items into a single list or tuple, and pickle that instead of pickling them individually. You can then unpack on the other side.
Pickle an integer describing the number of items first. That then tells you how many times to call pickle.load().
Just keep unpickling until you hit EOF.

回答3:

Have not previously tried to put more than one thing in a pickle file like that before, but good to see it is possible. Look at this answer. If you call it twice without the with it should get everything out:

f = open("TestPickle.pickle", "r")
ListNames = pickle.load(f)
ListNumbers = pickle.load(f)
f.close()

or you can keep the with like this:

with open("TestPickle.pickle", "rb") as f:
    ListNames,ListNumbers = pickle.load(f)

Then,

what if I have an unknown number of items in my pickle file with a number of Datatypes

Is it really a smart idea to just pour something into a pickle file so you don't know anymore what is in it?

来源：https://stackoverflow.com/questions/49261006/load-all-pickled-objects

标签

python

pickle