我希望代码阻止这个人并说"嘿,它必须全部小写" 然后让他们再次输入它,直到它全部小写。我正在尝试这样的事情:
username=input("Enter username ")
while username[::] .upper():
print("username cannot have capital letters")
username = input("Enter username ")
您可以使用string.islower()
来实现此目的:
username=input("Enter username ")
while not username.islower():
print("username cannot have capital letters")
username = input("Enter username ")
例如,如果要允许username = "@123"
,则可以改用
import string
username=input("Enter username ")
while any(c in string.ascii_uppercase for c in username):
print("username cannot have capital letters")
username = input("Enter username ")