当我尝试使用函数参数作为列表索引时，出现错误“列表索引必须是整数或切片，而不是元组”

Question

I try to use parameters of a function as a list indices, however I get

TypeError: list indices must be integers or slices, not a tuple.

days=['first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh', 'eighth', 'ninth', 'tenth', 'eleventh']

gifts=['and a patriage in a Pear tree', 'two Turtle Doves', 'three French Hens', 'four Calling Birds', 'five Gold Rings', 'six Geese-a-Laying', 'seven Swans-a-Swimming', 'eigth Maids-a-Milking', 'nine Ladies Dancing', 'ten Lords-a-Leaping', ' eleven Pipers Piping', 'twelve Drummers Drumming']

def recite( start_verse, end_verse):
    return ('On the '+days[start_verse+1] + ' day of Christmas my true love gave to me: '+ gifts[-1, end_verse])

print(recite(2,2))

Answer 1

The problem is here gifts[-1, end_verse] . You are using a tuple as an index.

You should use just an integer value instead. Maybe you meant one of these options:

gifts[-1 + end_verse]
gifts[end_verse - 1]
gifts[-1]
gifts[end_verse]

Answer 2

I think this gifts[-1, end_verse] is the problem. You can't have tuple as a list index. Maybe you wanted gifts[end_verse-1] here?

days=['first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh', 'eighth', 'ninth', 'tenth', 'eleventh']


gifts=['and a patriage in a Pear tree', 'two Turtle Doves', 'three French Hens', 'four Calling Birds', 'five Gold Rings', 'six Geese-a-Laying', 'seven Swans-a-Swimming', 'eigth Maids-a-Milking', 'nine Ladies Dancing', 'ten Lords-a-Leaping', ' eleven Pipers Piping', 'twelve Drummers Drumming']

def recite(start_verse, end_verse):
    return 'On the '+ str(days[start_verse+1]) + ' day of Christmas my true love gave to me: '+ str(gifts[end_verse-1])

print(recite(2,2))

Answer 3

Your return statement is incorrect in the recite function. The following code below is probably what you want. This is assuming that recite(1,1) is for the first day, recite(2,2) the second, and so on.

def recite(start_verse, end_verse):
   days=['first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh', 'eighth', 'ninth', 'tenth', 'eleventh', 'twelfth']
   gifts=['and a patriage in a Pear tree', 'two Turtle Doves', 'three French Hens', 'four Calling Birds', 'five Gold Rings', 'six Geese-a-Laying', 'seven Swans-a-Swimming', 'eigth Maids-a-Milking', 'nine Ladies Dancing', 'ten Lords-a-Leaping', ' eleven Pipers Piping', 'twelve Drummers Drumming']
   return("On the " + days[start_verse-1] + " day of Christmas my true love gave to me: " + gifts[end_verse-1])