What is the difference between pickle.dumps and pickle.dump, as well as pickle.loads and pickle.load?

pickle.dumps() serializes an object into a byte string, while pickle.dump() serializes an object into a file object (stream). Correspondingly, pickle.loads() deserializes a byte string back into an object, and pickle.load() deserializes an object from a file object (stream).

Examples:

import pickle

data = {'a': 1, 'b': 2}

# dumps: serialization into a byte string
pickled_string = pickle.dumps(data)
# b'\x80\x04\x95\x11\x00\x00\x00\x00\x00\x00\x00}\x94(X\x01\x00\x00\x00a\x94K\x01X\x01\x00\x00\x00b\x94K\x02u.'

# loads: deserialization from a byte string
unpickled_data_from_string = pickle.loads(pickled_string)
# {'a': 1, 'b': 2}

# dump: serialization into a file object
with open('data.pkl', 'wb') as f:
    pickle.dump(data, f) # writes bytes to the file data.pkl

# load: deserialization from a file object
with open('data.pkl', 'rb') as f:
    unpickled_data_from_file = pickle.load(f)
# {'a': 1, 'b': 2}

Summarizing:

Function	Input	Output	Purpose
pickle.dumps	Object	Bytes	Convert object to bytes
pickle.loads	Bytes	Object	Reconstruct object from bytes
pickle.dump	Object, file	None	Write object to a file
pickle.load	File	Object	Read object from a file