all Python 3picklefunction

pickle.dumps()

serialization

Turns an object into bytes in pickle format — for passing between processes, caching or storing in a database.

Syntax

data = pickle.dumps(obj, protocol=None, *, fix_imports=True, buffer_callback=None)

It returns bytes, not str: they cannot go into a text field or JSON without base64. The bytes depend on the protocol, the version and even key insertion order, so comparing dumps(a) == dumps(b) instead of a == b is wrong — equal dicts give different bytes. Lambdas, generators, open files, connections and locks cannot be pickled. The reverse, loads(), runs code from the data — accept such bytes only from yourself.

Examples

import pickle
print(type(pickle.dumps({'a': 1})).__name__)  # → bytes
print(pickle.dumps({'a': 1, 'b': 2}) == pickle.dumps({'b': 2, 'a': 1}))  # → False
try:
    pickle.dumps(lambda x: x)
except pickle.PicklingError:
    print('лямбду не сохранить')  # → лямбду не сохранить

See also

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