我正在使用2.7.6完成本书，我收到了一个错误。我逐行完成了这一点，以确保没有任何拼写错误。我（显然）对Python知之甚少，甚至不知道从哪里开始。我很感激我能得到的任何帮助。
以下是代码：
def get_specials():
monday = {'B': 'Horseradish omelet. Note: Better than it sounds.',
'L': 'Momma\'s Curry. Note: Can be made spicy.',
'D': 'Beef brisket. Note:Comes with au jus. That\'s pronounced "Oh jhoo", not "Ow Juice."'}
tuesday = {'B': 'Sausage gravy over biscuits. Note: Toast can be subbed.',
'L': 'Grilled cheese and tomato soup. Note: We have vegan cheese.',
'D': 'Meatloaf. Note: Comes with catsup on the top. Not optional.'}
wednesday = {'B': 'Horseradish omelet. Note: Better than it sounds.',
'L': 'Momma\'s Curry. Note: Can be made spicy.',
'D': 'Beef brisket. Note:Comes with au jus. That\'s pronounced "Oh jhoo", not "Ow Juice."'}
thursday = {'B': 'Sausage gravy over biscuits. Note: Toast can be subbed.',
'L': 'Grilled cheese and tomato soup. Note: We have vegan cheese.',
'D': 'Meatloaf. Note: Comes with catsup on the top. Not optional.'}
friday = {'B': 'Horseradish omelet. Note: Better than it sounds.',
'L': 'Momma\'s Curry. Note: Can be made spicy.',
'D': 'Beef brisket. Note:Comes with au jus. That\'s pronounced "Oh jhoo", not "Ow Juice."'}
saturday = {'B': 'Sausage gravy over biscuits. Note: Toast can be subbed.',
'L': 'Grilled cheese and tomato soup. Note: We have vegan cheese.',
'D': 'Meatloaf. Note: Comes with catsup on the top. Not optional.'}
sunday = {'B': 'Horseradish omelet. Note: Better than it sounds.',
'L': 'Momma\'s Curry. Note: Can be made spicy.',
'D': 'Beef brisket. Note:Comes with au jus. That\'s pronounced "Oh jhoo", not "Ow Juice."'}
specials = {'M': monday,
'T': tuesday,
'W': wednesday,
'R': thursday,
'F': friday,
'St': saturday,
'Sn': sunday}
def print_special(special):
print "The special is:"
print special
print "*"*15
def get_day():
while True:
day = raw_input("Day (M/T/W/R/F/St/Sn): ")
if day.upper() in ['M', 'T', 'W', 'R', 'F', 'ST', 'SN']:
return day.upper()
else:
print "I'm sorry, but {} isn't valid.".format(day)
def get_time():
while True:
time = raw_input("Time (B/L/D): ")
if time.upper() in ['B', 'L', 'D']:
return time.upper()
else:
print "I'm sorry, but {} isn't a valid time.".format(time)
def main():
specials = get_specials()
print "This script will tell you the specials for any day of the week, and any time."
while True:
day = get_day()
special = specials[day]
time = get_time()
print_special(special[time])
another = raw_input("Do you want to check another day and time? (Y/N")
if another.lower() == 'n':
break
if __name__ == '__main__':
main()
错误：
Traceback (most recent call last):
File "C:/Users/User/Desktop/Python/9.py", line 71, in <module>
main()
File "C:/Users/User/Desktop/Python/9.py", line 64, in main
special = specials[day]
TypeError: 'NoneType' object has no attribute '__getitem__'
答案 0 :(得分：4)
get_specials函数最后应返回specials字典：
def get_specials():
# …
specials = {'M': monday,
'T': tuesday,
'W': wednesday,
'R': thursday,
'F': friday,
'St': saturday,
'Sn': sunday}
return specials
这样，当你specials = get_specials()时，你实际上得到了该词典的内容。如果不这样做，则调用get_specials()将返回None（即没有），当然不会包含任何信息。
答案 1 :(得分：2)
您的问题是get_specials()没有返回声明。由于它没有返回任何东西，行
specials = get_specials()
将specials指定为None，以便specials[day]尝试查找None中的索引，该索引因您看到的错误而失败。