【Python】json编码和解码器

json编码和解码

JSON (JavaScript Object Notation) 是一种轻量级的数据交换格式。Python3 中可以使用 json 模块来对 JSON 数据进行编解码，它包含了两个函数：

• json.dumps(): 对数据进行编码。
• json.loads(): 对数据进行解码。

Python 编码为 JSON 类型转换对应表：

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

JSON 解码为 Python 类型转换对应表：

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

函数原型：

json.dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True, \
           allow_nan=True, cls=None, indent=None, separators=None, default=None, \
           sort_keys=False, **kw)

 

1. 例1：

import json
print(json.dumps([1, 2, 3, {'4': 5, '6': 7}], separators=(',', ':')))
print(json.dumps([1, 2, 3, {'4': 5, '6': 7}], separators=(',', ': ')))
print(json.dumps([1, 2, 3, {'4': 5, '6': 7}], separators=(', ', ': ')))
print(json.dumps([1, 2, 3, {'4': 5, '6': 7}], indent=2, separators=(', ', ': ')))
print(json.dumps([1, 2, 3, {'4': 5, '6': 7}], indent=4, separators=(', ', ': ')))

输出：

[1,2,3,{"4":5,"6":7}]
[1,2,3,{"4": 5,"6": 7}]
[1, 2, 3, {"4": 5, "6": 7}]
[
  1, 
  2, 
  3, 
  {
    "4": 5, 
    "6": 7
  }
]
[
    1, 
    2, 
    3, 
    {
        "4": 5, 
        "6": 7
    }
]

import json
 
# Python 字典类型转换为 JSON 对象
data1 = {
    'no' : 1,
    'name' : 'Runoob',
    'url' : 'http://www.runoob.com'
}
 
json_str01 = json.dumps(data1)
json_str02 = json.dumps(data1,  indent=4)
print ("Python 原始数据：", repr(data1))
print ("JSON 对象：", json_str01)
print ("JSON 对象：", json_str02)
 
# 将 JSON 对象转换为 Python 字典
data2 = json.loads(json_str01)
print ("data2['name']: ", data2['name'])
print ("data2['url']: ", data2['url'])

输出：

Python 原始数据： {'no': 1, 'name': 'Runoob', 'url': 'http://www.runoob.com'}
JSON 对象： {"no": 1, "name": "Runoob", "url": "http://www.runoob.com"}
JSON 对象： {
    "no": 1,
    "name": "Runoob",
    "url": "http://www.runoob.com"
}
data2['name']:  Runoob
data2['url']:  http://www.runoob.com

 

函数原型：

json.loads(s, *, cls=None, object_hook=None, parse_float=None, \
           parse_int=None, parse_constant=None, object_pairs_hook=None, **kw)

 

文件名为data.json:

# importing the module
import json
 
# Opening JSON file
with open('data.json') as json_file:
    data = json.load(json_file)
 
    # Print the type of data variable
    print("Type:", type(data))
 
    # Print the data of dictionary
    print("\nPeople1:", data['people1'])
    print("\nPeople2:", data['people2'])

输出：

 

# importing the module
import json
 
# Opening JSON file
with open('data.json') as json_file:
    data = json.load(json_file)
 
    # for reading nested data [0] represents
    # the index value of the list
    print(data['people1'][0])
     
    # for printing the key-value pair of
    # nested dictionary for loop can be used
    print("\nPrinting nested dictionary as a key-value pair\n")
    for i in data['people1']:
        print("Name:", i['name'])
        print("Website:", i['website'])
        print("From:", i['from'])
        print()

输出：

 

# Python program to read
# json file

import json

# Opening JSON file
f = open('data.json')

# returns JSON object as
# a dictionary
data = json.load(f)

# Iterating through the json
# list
for i in data['emp_details']:
	print(i)

# Closing file
f.close()

 

参考资料

1. json编码和解码