变量为空代表false

name = ''#名字为空即代表False
while not name:#not name=False即 真，将执行循环体
    print('Enter your name:')
    name = input()#给name赋值，如输入了空以外值，不会再有下一个循环while
    print('How many guests will you have?')
    numOfGuests = int(input())#输入的值(必须为数字)，把它转为整型数值
    if numOfGuests:#若输入了0以外的值【true】则执行下一步打印，否则跳过下一句
        print('Be sure to have enough room for all your guests.')
print('Done')