二十六、python中json学习

1.json序列介绍：提供4个关键字：dumps，dump，loads，load（与pickle用法完全相同）

　　语法：f.write(bytes（json.dumps(dict)，encoding="utf-8"）)

　　　　　r=json.loads(f.read().decode("utf-8"))

　　将字典存入文件，由于字典格式不能转化成字节格式的，所以引入json

　　A.将一个字典转化成json序列存入一个文件

import json accounts={ 1000:{ 'name':'Tom', 'email':'[e-mail]', 'passwd':'abc123', 'balance':20000, 'phone':'44165465', 'bank_acc':{ 'ICBC':165116161, 'CBC':16516516516, 'ABC':656151616516 } }, 1001:{ 'name':'Tom1', 'email':'[e-mail]', 'passwd':'abc1123', 'balance':210000, 'phone':'441654165', 'bank_acc':{ 'ICBC':16511161611, 'CBC':165165165161, 'ABC':6561516165161 } } } print (json.dumps(accounts)) #将字典转成json序列 f=open("account.db","wb") #写入文件account.db f.write(bytes(json.dumps(accounts),encoding="utf-8")) #写入文件account.db f.close() ------------------------------------------------------------------- {"1000": {"name": "Tom", "email": "[e-mail]", "passwd": "abc123", "balance": 20000, "phone": "44165465", "bank_acc": {"ICBC": 165116161, "CBC": 16516516516, "ABC": 656151616516}}, "1001": {"name": "Tom1", "email": "[e-mail]", "passwd": "abc1123", "balance": 210000, "phone": "441654165", "bank_acc": {"ICBC": 16511161611, "CBC": 165165165161, "ABC": 6561516165161}}}

　　B.重新创建一个新的python文件读取account.db中的内容：

import pickle account_file=open("account.db","rb") #打开文件 account_dict=json.loads(account_file.read().decode("utf-8")) #以json加载文件 #print (account_dict) account_file.close() #print(type(account_dict['1000']['balance'])) account_dict['1000']['balance'] -= 500 #取字典中balance然后减500 print (account_dict) f=open("account.db","wb") f.write(bytes(json.dumps(account_dict),encoding="utf-8")) #将变更后的内容dumps入文件 f.close() print (account_dict) ----------------------------------------------------------------------------- {'1000': {'name': 'Tom', 'email': '[e-mail]', 'passwd': 'abc123', 'balance': 20000, 'phone': '44165465', 'bank_acc': {'ICBC': 165116161, 'CBC': 16516516516, 'ABC': 656151616516}}, '1001': {'name': 'Tom1', 'email': '[e-mail]', 'passwd': 'abc1123', 'balance': 210000, 'phone': '441654165', 'bank_acc': {'ICBC': 16511161611, 'CBC': 165165165161, 'ABC': 6561516165161}}} {'1000': {'name': 'Tom', 'email': '[e-mail]', 'passwd': 'abc123', 'balance': 19500, 'phone': '44165465', 'bank_acc': {'ICBC': 165116161, 'CBC': 16516516516, 'ABC': 656151616516}}, '1001': {'name': 'Tom1', 'email': '[e-mail]', 'passwd': 'abc1123', 'balance': 210000, 'phone': '441654165', 'bank_acc': {'ICBC': 16511161611, 'CBC': 165165165161, 'ABC': 6561516165161}}} {'1000': {'name': 'Tom', 'email': '[e-mail]', 'passwd': 'abc123', 'balance': 19500, 'phone': '44165465', 'bank_acc': {'ICBC': 165116161, 'CBC': 16516516516, 'ABC': 656151616516}}, '1001': {'name': 'Tom1', 'email': '[e-mail]', 'passwd': 'abc1123', 'balance': 210000, 'phone': '441654165', 'bank_acc': {'ICBC': 16511161611, 'CBC': 165165165161, 'ABC': 6561516165161}}}