What is the difference between json and pickle in Python?

What is the difference between json and pickle in Python?

In Python, we often need to save data from a program to a file or read it from a file. JSON and pickle are two commonly used data serialization and deserialization methods. They can all convert Python data structures into strings or byte streams for easy storage or transmission, and can also restore strings or byte streams to the original Python data structures. However, there are some differences between JSON and pickle, which are detailed below.

First of all, JSON is a lightweight data exchange format with strong readability and good cross-language compatibility. When using JSON for data serialization, Python's data structure will be converted into a string form that can be parsed by other programming languages, called a JSON string. Pickle is Python's unique serialization method, which can directly convert Python objects into byte streams instead of string form.

Secondly, the data types supported by JSON are relatively simple, including strings, numbers, Boolean values, lists, dictionaries and None. And pickle can serialize almost any Python object, including custom classes and functions, even instance methods and closures. This is because pickle uses Python's specific protocol to serialize objects, so only Python can deserialize data in pickle format.

Let’s take a look at a specific code example:

import json
import pickle

# 定义一个Python字典
data = {'name': 'Tom', 'age': 25, 'gender': 'male'}

# 使用JSON进行序列化
json_str = json.dumps(data)
print('JSON字符串:', json_str)

# 使用pickle进行序列化
pickle_data = pickle.dumps(data)
print('Pickle字节流:', pickle_data)

# 使用JSON进行反序列化
json_data = json.loads(json_str)
print('JSON反序列化:', json_data)

# 使用pickle进行反序列化
unpickle_data = pickle.loads(pickle_data)
print('Pickle反序列化:', unpickle_data)

The running results are as follows:

JSON字符串: {"name": "Tom", "age": 25, "gender": "male"}

JSON反序列化: {'name': 'Tom', 'age': 25, 'gender': 'male'}
Pickle反序列化: {'name': 'Tom', 'age': 25, 'gender': 'male'}

As can be seen from the code example, what is obtained after serialization using JSON is JSON data in the form of a string, and serialization using pickle results in a byte stream. During deserialization, JSON can directly convert the JSON string into a Python dictionary, and pickle can directly restore the byte stream to Python's original data structure.

To sum up, there are some differences between JSON and pickle in terms of data serialization and deserialization methods, data type support and cross-language compatibility. We can choose the appropriate method to save and transmit data according to actual needs.

The above is the detailed content of What is the difference between json and pickle in Python?. For more information, please follow other related articles on the PHP Chinese website!