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Python3 JSON data analysis

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

Python3 json module can be used to encode and decode JSON data, which contains two functions:

  • json.dumps (): encoding data.
  • json.loads (): data is decoded.

In json codec process, python and json type of primitive types will be converted to each other, the specific transformation control as follows:

Python JSON encoded as a 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 decodes the 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

json.dumps and json.loads examples

The following example demonstrates Python data structures into JSON:


import json

# Python 字典类型转换为 JSON 对象
data = {
    'no' : 1,
    'name' : 'w3big',
    'url' : ''

json_str = json.dumps(data)
print ("Python 原始数据:", repr(data))
print ("JSON 对象:", json_str)

Execute the above code output results:

Python 原始数据: {'url': '', 'no': 1, 'name': 'w3big'}
JSON 对象: {"url": "", "no": 1, "name": "w3big"}

The results can be seen through the output, followed by the simple types by encoding its original repr () output is very similar.

Then the above example, we can convert a JSON-encoded string back to a Python data structure:


import json

# Python 字典类型转换为 JSON 对象
data1 = {
    'no' : 1,
    'name' : 'w3big',
    'url' : ''

json_str = json.dumps(data1)
print ("Python 原始数据:", repr(data1))
print ("JSON 对象:", json_str)

# 将 JSON 对象转换为 Python 字典
data2 = json.loads(json_str)
print ("data2['name']: ", data2['name'])
print ("data2['url']: ", data2['url'])

Execute the above code output results:

ython 原始数据: {'name': 'w3big', 'no': 1, 'url': ''}
JSON 对象: {"name": "w3big", "no": 1, "url": ""}
data2['name']:  w3big

If you want to deal with is the file instead of a string, you can usejson.dump () and json.load ()to encode and decode JSON data. E.g:

# 写入 JSON 数据
with open('data.json', 'w') as f:
    json.dump(data, f)

# 读取数据
with open('data.json', 'r') as f:
    data = json.load(f)

For more information, please refer to: