s1 = '{"lid":2,"date":"20190211","type":"1,2","page":1}' # dict的key和value用双引号
s2 = "{'lid':2,'date':'20190211','type':'1,2','page':1}" # 单引号

print(type(s1),type(s2)) # <class 'str'> <class 'str'>

import json
s11 = json.loads(s1)
print(s11,type(s11)) # <class 'dict'>

s22 = json.loads(s2) #报错jExpecting property name enclosed in double quotes 必须双引号
print(s22,type(s22))

s33 = eval(s1)
print(s33,type(s33))

s44 = eval(s2)
print(s44,type(s44))

import ast
s55 = ast.literal_eval(s1)
s66 = ast.literal_eval(s2)
print(s55,s66,type(s55),type(s66))