python如何将一串字符串转换为字典

>>> import json

>>> user_info= '{"name" : "john", "gender" : "male", "age": 28}'

>>> user_dict = json.loads(user_info)

>>> user_dict

{u'gender': u'male', u'age': 28, u'name': u'john'}

>>> import json

>>> user_info = "{'name' : 'john', 'gender' : 'male', 'age': 28}"

# 由于字符串使用单引号，会导致运行出错

>>> user_dict = json.loads(user_info)

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 339, in loads

    return _default_decoder.decode(s)

  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 364, in decode

    obj, end = self.raw_decode(s, idx=_w(s, 0).end())

  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 380, in raw_decode

    obj, end = self.scan_once(s, idx)

ValueError: Expecting property name: line 1 column 2 (char 1)

>>> usr_info = '{"name" : "john", "gender" : "male", "age": 28}'

>>> user_dict = eval(user_info)

>>> user_dict

{'gender': 'male', 'age': 28, 'name': 'john'}

>>> user_info = "{'name' : 'john', 'gender' : 'male', 'age': 28}"

>>> user_dict = eval(user_info)

>>> user_dict

{'gender': 'male', 'age': 28, 'name': 'john'}

# 让用户输入 `user_info`

>>> user_info = raw_input('input user info: ')

# 输入 {"name" : "john", "gender" : "male", "age": 28}，没问题

>>> user_dict = eval(user_info)

# 输入 __import__('os').system('dir')，user_dict 会列出当前的目录文件！

# 再输入一些删除命令，则可以把整个目录清空了！

>>> user_dict = eval(user_info)

>>> import ast

>>> user = '{"name" : "john", "gender" : "male", "age": 28}'

>>> user_dict = ast.literal_eval(user)

>>> user_dict

{'gender': 'male', 'age': 28, 'name': 'john'}

user_info = "{'name' : 'john', 'gender' : 'male', 'age': 28}"

>>> user_dict = ast.literal_eval(user)

>>> user_dict

{'gender': 'male', 'age': 28, 'name': 'john'}