輸入1，輸出：if

輸入2，輸出：elif

輸入其他數值，輸出：else

輸入非數字，輸出：except

def greeting3(name3, lang3=1):
        if lang3 == 1:
            return ‘中文‘ + name3
        elif lang3 == 2:
            return ‘英文‘ + name3
        else:
            return ‘輸入的不是1或2‘
while True:

        try:
            #lang3 = float(input(‘輸入一個數字吧：‘))
 

            lang3 =int(input(‘輸入一個數字吧：‘))
            name3 = ‘我是蔣‘
            print(greeting3(name3, lang3))
            # break
        except ValueError:
            print(‘輸入的不是數字吧‘)

函數及while實例