类型注解-Python

师从黑马程序员

类型注解的语法

 

类型注释的限制

import json
import random

var_1 : int=10
var_2 : str="itheima"
var_3 : bool=True

class Student:
    pass
stu :Student=Student()

my_list:list =[1,2,3]
my_tuple:tuple=(1,2,3)
my_dict:dict={"itheima":666}

my_list:list[int] =[1,2,3]
my_tuple:tuple[int,str,bool]=(1,"itheima",True)
my_dict:dict[str,int]={"itheima":666}

var_1=random.randint(1,10)  #type: int
var_2=json.loads('{"name":"zhangsan"}') #type:dict[str,str]
def func():
    return 10
var_3=func()    #type:int

var_4:int="ithema"
var_5:int=123  #不会报错

函数和方法的类型注解

形式参数注解

返回值注解

def add(x:int,y:int):
    return x+y

def func(data:list)->list:
    return data

print(func(1))

Union类型注解

变量

函数

from typing import Union#导包

my_list:list[Union[int,str]]=[1,2,"itheima","itcast"]

def func(data:Union[int,str])->Union[int,str]:
    pass
func()

若有侵权，请联系作者