python中eval()和json.dumps的使用

在python中通过requests.get(url)获取json数据，此时可能需要eval进行解析。

 # -*- coding: utf-8 -*-
 import requests

 r = requests.get(url='your url address')  # 最基本的GET请求
 # print r.content
 # print '......................'
 # print len(r.json()
 # print '......................'
 # print len(r.json()['data'])
 # print '......................'
 print r.json()['data'][6]['type']          # area
 print '......................'
 print r.json()['data'][6]['radarcoor']
 print '......................'
 print r.json()['data'][6]['radarcoor'][0]      # 错误
 print '......................'
 print eval("r.json()['data'][6]['radarcoor']")[0]           # 错误
 print '......................'
 print eval("("+r.json()['data'][6]['radarcoor']+")")[0]       # 正确的写法

此时r.json()返回：

r.json()['data'][6]['radarcoor']返回：

要获取其中每一项，则需要使用eval()函数进行解析：

2.json.dumps()

功能：将python中的数据类型转换成str类型

 # json.dumps()
 mylist = [123, {'name': 'dragon'}, {'location': ('ch', 'nt')}]
 encoded_json = json.dumps(mylist)
 print isinstance(encoded_json, str)  # True
 print encoded_json       # [123, {"name": "dragon"}, {"location": ["ch", "nt"]}]

 # json.loads()
 # decoded_json = json.loads(encoded_json)
 # print isinstance(decoded_json, list)      # True
 # print decoded_json     # [123, {u'name': u'dragon'}, {u'location': [u'ch', u'nt']}]

 # eval()
 decoded_json = eval(encoded_json)
 print isinstance(decoded_json, list)  # True
 print decoded_json       # [123, {'name': 'dragon'}, {'location': ['ch', 'nt']}]