How Can I Save and Load Custom Python Objects for Data Persistence?

Saving Python Objects for Data Persistence

Question:

I have created a custom Python object and would like to save it for later use. How can I achieve this for data persistence?

Saving Objects with the Pickle Module:

The Pickle module in Python's standard library provides a convenient way to save objects for data persistence. Consider the following example with a custom object:

import pickle

class Company:
    def __init__(self, name, value):
        self.name = name
        self.value = value

company1 = Company('banana', 40)

To save this object, we can use the following code:

with open('company_data.pkl', 'wb') as outp:
    pickle.dump(company1, outp, pickle.HIGHEST_PROTOCOL)

This will create a pickle file containing the serialized representation of the company1 object.

Reading Saved Objects:

Once saved, the object can be deserialized and retrieved later:

with open('company_data.pkl', 'rb') as inp:
    company1 = pickle.load(inp)

company1 now contains the original object, with its name and value attributes intact.

Additional Considerations:

• cPickle vs Pickle: cPickle, the C version of pickle, offers improved performance. If available, use import cPickle as pickle.
• Data Stream Formats (Protocols): Pickle supports different data stream formats. For highest compatibility, use pickle.HIGHEST_PROTOCOL (-1).
• Saving Multiple Objects: Pickle can store multiple objects in a single file. Use containers like lists or dictionaries to group them.

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