How to read and write json files using python

JSON (JavaScript Object Notation) is a lightweight data exchange format. It is based on a subset of ECMAScript. JSON uses a completely language-independent text format, but also uses conventions similar to the C language family (including C, C++, Java, JavaScript, Perl, Python, etc.). These properties make JSON an ideal data exchange language. It is easy for humans to read and write, and it is also easy for machines to parse and generate (generally used to increase network transmission rates).

JSON consists of list and dict respectively in python.

These are two modules used for serialization:

• json: used to convert between strings and python data types

• pickle: Used to convert between python-specific types and python data types

The Json module provides four functions: dumps, dump, loads, load

The pickle module provides four functions: dumps, dump, loads, load

json dumps converts the data type into a string dump converts the data type into a string and stores it in the file loads string Convert to data type Load converts the file opening from a string to a data type

json can exchange data between different languages, while pickle is only used between python. JSON can only serialize the most basic data types, and JSON can only serialize commonly used data types (lists, dictionaries, lists, strings, numbers, etc.), such as date formats and class objects! Josn won't do it. Pickle can serialize all data types, including classes and functions.

Example:

dumps: Convert a dictionary in python to a string

import json

test_dict = {'bigberg': [7600, {1: [['iPhone', 6300], ['Bike', 800], ['shirt', 300]]}]}
print(test_dict)
print(type(test_dict))
#dumps 将数据转换成字符串
json_str = json.dumps(test_dict)
print(json_str)
print(type(json_str))

##loads: Convert a string to a dictionary

new_dict = json.loads(json_str)
print(new_dict)
print(type(new_dict))

dump: Write data into a json file

with open("../config/record.json","w") as f:
json.dump(new_dict,f)
print("加载入文件完成...")

load: Open the file and put the string Convert to data type

with open("../config/record.json",'r') as load_f:
load_dict = json.load(load_f)
print(load_dict)
load_dict['smallberg'] = [8200,{1:[['Python',81],['shirt',300]]}]
print(load_dict)
with open("../config/record.json","w") as dump_f:
json.dump(load_dict,dump_f)

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