python出现indexerror,Python：IndexError：列表索引超出范围错误

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I am stuck! I get a IndexError: list index out of range Error.

def makeInverseIndex(strlist):

numStrList = list(enumerate(strlist))

n = 0

m = 0

dictionary = {}

while (n < len(strList)-1):

while (m < len(strlist)-1):

if numStrList[n][1].split()[m] not in dictionary:

dictionary[numStrList[n][1].split()[m]] = {numStrList[n][0]}

m = m+1

elif {numStrList[n][0]} not in dictionary[numStrList[n][1].split()[m]]:

dictionary[numStrList[n][1].split()[m]]|{numStrList[n][0]}

m = m+1

n = n+1

return dictionary

it gives me this error

>>> makeInverseIndex(s)

Traceback (most recent call last):

File "", line 1, in

File "./inverse_index_lab.py", line 23, in makeInverseIndex

if numStrList[n][1].split()[m] not in dictionary:

IndexError: list index out of range

I don't get it... what causes this? It happens even when I change the conditions of the while loop. I don't get what is the problem. I am pretty new at this, so explain it like you would if a piece of broccoli asked you this question.

Edit:

Thanks guys, I forgot to mention examples of input, I want to input something like this:

L=['A B C', 'B C E', 'A E', 'C D A']

and get this as output:

D={'A':{0,2,3}, 'B':{0,1}, 'C':{0,3}, 'D':{3}, 'E':{1,2}}

so to create a dictionary that shows where in the list you might find a 'A' for example. It should work with a huge list. Do anyone have any tips? I want it to iterate and pick out each letter and then assign them a dictionary value.

Edit number two:

Thanks to great help from you guys my code looks beautiful like this:

def makeInverseIndex(strList):

numStrList = list(enumerate(strList))

n = 0

dictionary = {}

while (n < len(strList)):

for word in numStrList[n][1].split():

if word not in dictionary:

dictionary[word] = {numStrList[n][0]}

elif {numStrList[n][0]} not in dictionary[word]:

dictionary[word]|={numStrList[n][0]}

n = n+1

return dictionary

But I still manage to get this error when I try to run the module:

>>> makeInverseIndex(L)

Traceback (most recent call last):

File "", line 1, in

File "./inverse_index_lab.py", line 21, in makeInverseIndex

for word in numStrList[n][1].split():

NameError: global name 'StrList' is not defined

I do not see where the error can come from.

解决方案

Good to see some smart veggies programming.

First, your question. Like @Vasiliy said, you have 3 indices. The n is alright, since you protect it with your while condition. The 1 is fine since enumerate always generates 2 things. That just leaves m. This is your problem.

Let's say you have N elements in strlist. For each element e in strlist, you apply split() to it. The number of elements in e.split() is not always equal to N. The while condition for m guards against N, not against len(e.split()), hence the index out of range.

To solve this, split the string first, and then loop through it. While you're at it, might as well get rid of m altogether, splitting the string only once, and gain some performance. Plus, you never reset your m, which just grows and grows.

while (n < len(strList)):

for word in numStrList[n][1].split():

if word not in dictionary:

dictionary[word] = {numStrList[n][0]}

elif {numStrList[n][0]} not in dictionary[word]:

dictionary[word]|={numStrList[n][0]}

n = n+1

Second, your while conditions are too restrictive. n < len(strlist) is fine.