python通过json读写序列类型的数据文件

 import json
 class a:
     def writeReadJson(self):
         list2 =['',5.,7,'']
         with open("test.txt",'w') as f:
             json.dump(list2,f)#将列表写入f文件
         with open("test.txt", 'r') as f1:
             j = json.load(f1)#将f1文件内容加载并赋给j
         print(j)  #输出{'3': 6, '5': 8}
         print(json.dumps(list2))#输出["1", 5.0, 7, "3"]
 a().writeReadJson()