题解 | #禁止重复注册#

#重点是两个列表中的名字大小写不同，要转化成同样是小写进行比较
current_users=['Niuniu','Niumei','GURR','LOLO']#存在用户
new_users=['GurR','Niu Ke Le','LoLo','Tuo Rui Chi']#新用户
current=[a.lower() for a in current_users]#存在用户转成小写
for i in new_users:
    if i.lower() in current:#新用户转成小写来进行比较
        print('The user name',i,'has already been registered! Please change it and try again!')
    else:print('Congratulations, the user name',i,'is available!')