python json模塊
#!/usr/bin/env python
# -*- coding:utf-8 -*-
# @Time : 2017/11/14 14:24
# @Author : lijunjiang
# @File : Json.py
‘‘‘python json模塊 ‘‘‘
import codecs
import json
"""
JSON(JavaScript Object Notation) 是一種輕量級的數據交換格式。易於人閱讀和編寫。同時也易於機器解析和生成。
Pyhton的Json模塊提供了把內存中的對象序列化的方法
"""
# json.dumps 和 json.dump
# dump的功能是把python 對象 encode 為json對象的一個編碼過程
# json 模塊提供了json.dumps 和 json.dump 方法,區別是dump 直接到文件,dumps 到一個字符串,s可理解為string
# json.dumps :把python對象編碼為string
data = [{‘a‘:‘A‘, ‘b‘:(2, 4), ‘c‘:3.0}]
print(‘DATA: {0}‘,format(data))
print(type(data))
data_string = json.dumps(data)
print(‘JSON: {0}‘.format(data_string))
print(type(data_string))
‘‘‘
C:\Python27\python.exe D:/Python/modules/Json.py
DATA: {0} [{‘a‘: ‘A‘, ‘c‘: 3.0, ‘b‘: (2, 4)}]
<type ‘list‘>
JSON: [{"a": "A", "c": 3.0, "b": [2, 4]}]
<type ‘str‘>
Process finished with exit code 0
‘‘‘
# json.dump :把python 對象寫入文件
# python 對象不能直接寫入到文件,需要將其序列化之後才可以
# 直接將python對象寫入到方件
data = [{‘a‘
with codecs.open(‘Json.txt‘, ‘w‘) as f:
f.write(data)
‘‘‘
C:\Python27\python.exe D:/Python/modules/Json.py
Traceback (most recent call last):
File "D:/Python/modules/Json.py", line 49, in <module>
f.write(data)
TypeError: expected a string or other character buffer object
Process finished with exit code 1
‘‘‘
# 直接將phthon 對象寫入文件會報:TypeError: expected a string or other character buffer object 錯誤
# 通過json.dump 寫入文件
data = [{‘a‘:‘A‘, ‘b‘:(2, 4), ‘c‘:3.0}]
with codecs.open(‘Json.txt‘, ‘w‘) as f:
json.dump(data, f)
with codecs.open(‘Json.txt‘, ‘r‘) as f:
json_txt = f.read()
print(json_txt)
‘‘‘
C:\Python27\python.exe D:/Python/modules/Json.py
[{"a": "A", "c": 3.0, "b": [2, 4]}]
Process finished with exit code 0
‘‘‘
# json.load 和 json.loads
# 作用是將 json對象decode解碼成python 可以識別的對象
# 與dump和dumps對應,json.load方法是基於文件的,json.loads 是基於字符串的
# json.loads : 將json 字符串 decode 為 Python 對象
data_str1 = ‘[{"a": "A", "c": 3.0, "b": [2, 4]}]‘
data_str2 = ‘{"a": "A", "c": 3.0, "b": [2, 4]}‘
print(‘data_str1: {0}‘.format(data_str1))
print(type(data_str1))
print(‘data_str2: {0}‘.format(data_str2))
print(type(data_str2))
data_py1 = json.loads(data_str1)
data_py2 = json.loads(data_str2)
print(‘data_py1: {0}‘.format(data_py1))
print(type(data_py1))
print(‘data_py2: {0}‘.format(data_py2))
print(type(data_py2))
‘‘‘
C:\Python27\python.exe D:/Python/modules/Json.py
data_str1: [{"a": "A", "c": 3.0, "b": [2, 4]}]
<type ‘str‘>
data_str2: {"a": "A", "c": 3.0, "b": [2, 4]}
<type ‘str‘>
data_py1: [{u‘a‘: u‘A‘, u‘c‘: 3.0, u‘b‘: [2, 4]}]
<type ‘list‘>
data_py2: {u‘a‘: u‘A‘, u‘c‘: 3.0, u‘b‘: [2, 4]}
<type ‘dict‘>
Process finished with exit code 0
‘‘‘
# 上例中,將字符串 data_str1 decode 為python 的list ,將data_str2 decode 為python的 dict 對象
# json.load : 將json 方件 decode 解碼為 python 對象
with codecs.open(‘Json.txt‘,‘r‘) as f:
print(‘f type: {}‘.format(type(f)))
Json_txt = f.read()
print(‘Json.txt info : {}‘.format(Json_txt))
with codecs.open(‘Json.txt‘, ‘r‘) as f:
json_txt_py = json.load(f)
print(‘json_txt_py: {}‘.format(json_txt_py))
print(type(json_txt_py))
‘‘‘
C:\Python27\python.exe D:/Python/modules/Json.py
f type: <type ‘file‘>
Json.txt info : [{"a": "A", "c": 3.0, "b": [2, 4]}]
json_txt_py: [{u‘a‘: u‘A‘, u‘c‘: 3.0, u‘b‘: [2, 4]}]
<type ‘list‘>
Process finished with exit code 0
‘‘‘
轉載自:https://www.cnblogs.com/lijunjiang2015/p/7833167.html
python json模塊