题解 | #禁止重复注册#

current_users = ['Niuniu','Ninmei','GURR','LOLO']
new_users = ['GurR','Niu Ke Le','LoLo','Tuo Rui Chi']
number = 0
for x in range(len(new_users)):
    for y in range(len(current_users)):
        if new_users[x].lower() == current_users[y].lower():
            number = 1
            break
        else:
            number = 2
            continue
    if number == 2:
        print("Congratulations, the user name " + new_users[x] + " is available!")
    if number == 1:
        print("The user name " + new_users[x] + " has already been registered! Please change it and try again!")