python中if else流程判断

_username='Lily'

_password=''

username=input("username:")

password=input("password:")

if _username==username and _password==password:

    print("Welcome user {name} login....".format(name=username))

else:

    print("Invalid username or password")

输入结果

F:\py\pyProject\venv\Scripts\python.exe F:/py/pyProject/Day3.py

username:Lily

password:123

Welcome user Lily login....

Process finished with exit code 0

2.

grade_of_Lucy = 85

guess_grade = int(input("guess grade:"))

if guess_grade == grade_of_Lucy:

    print("yes,you got it")

elif guess_grade > grade_of_Lucy:

    print("think bigger")

else:

    print("think smaller")