题解 | #禁止重复注册#

from operator import ne
current_users = ['Niuniu','Niumei','GURR','LOLO']
new_users     = ['GurR','Niu Ke Le','LoLo','Tuo Rui Chi']
current_users_t= []

for name in current_users:
    current_users_t.append(name.lower())

for name in new_users:
    if name.lower() in current_users_t:
        print(f"The user name {name} has already been registered! Please change it and try again!")
    else:
        print(f"Congratulations, the user name {name} is available!")

将两个列表内的名字都转成小写再比较