Python reads and writes json files (dump, load), and processes data in json format (dumps, loads)

 

JSON (JavaScript Object Notation) is a lightweight data interchange format. It is based on a subset of ECMAScript.

1. json.dumps() and json.loads() are json format processing functions (it can be understood that json is a string)

 

1. The json.dumps() function encodes a list of Python data types in json format (it can be understood that the json.dumps() function converts a dictionary into a string)
2. The json.loads() function converts json format data into a dictionary (it can be understood that the json.loads() function converts a string into a dictionary)

 

During the encoding and decoding process of json, the original type of python and the json type will be converted to each other. The specific conversion comparison is as follows:

Python encoding to JSON type conversion correspondence table:

Python	JSON
dict	object
list, tuple	array
str	string
int, float, int- & float-derived Enums	number
True	true
False	false
None	null

JSON decoding to Python type conversion correspondence table:

JSON	Python
object	dict
array	list
string	str
number (int)	int
number (real)	float
true	True
false	False
null	None

 

2. json.dump() and json.load() are mainly used to read and write json file functions

Examples are as follows:

import json,time
# save data to json file
def store(data):
    with open( ' data.json ' , ' w ' ) as fw:
         #Convert the dictionary to a string 
        # json_str = json.dumps(data) 
        # fw.write(json_str) #The 
        above two sentences are equivalent to the following 
        json. dump(data,fw)
 # load json data from file 
def load():
    with open('data.json','r') as f:
        data = json.load(f)
        return data


if __name__ == "__main__":
    json_data = '{"login":[{"username":"aa","password":"001"},{"username":"bb","password":"002"}],"register":[{"username":"cc","password":"003"},{"username":"dd","password":"004"}]}'
    # 函数是将json格式数据转换为字典
    data = json.loads(json_data)
    store(data)

    data = load()
    print(data)

 

Summarize:

The one without s is used to manipulate files, and the one with s is used for data type conversion.