题解 | #禁止重复注册#

#列表表达式  [表达式 for 变量 in 可迭代对象 if 条件]
#squares = [x**2 for x in range(10)]
#squares_of_four = [x**2 for x in range(10) if x**2 % 4 == 0]


current_users = ["Niuniu", "Niumei", "GURR", "LOLO"]
new_users = ["GurR", "Niu Ke Le", "LoLo", "Tuo Rui Chi"]
current_users_L = [i.lower() for i in current_users]
for i in new_users:
    if i.lower() in current_users_L:
        print(
            "The user name {} has already been registered! Please change it and try again!".format(
                i
            )
        )
    else:
        print("Congratulations, the user name {} is available!".format(i))