## Question:

Can someone tell me what error I have in my code if it is not too much trouble.

```
def CreaLista(k):
L = []
for i in range(k+1):
L.append(0)
return L
def CountingSort(A,k):
C=CreaLista(k)
B=CreaLista(len(A)-1)
for j in range(1, len(A)):
C[A[j]] = C[A[j]]+1
for i in range(1, k+1):
C[i]=C[i]+C[i-1]
for j in range(len(A)-1,0,-1):
B[C[A[j]]]=A[j]
C[A[j]]=C[A[j]]-1
return B
lista = [0,9,7,81,4,5,68,3,541]
k = len(lista[1:])
CountingSort(lista, k)
```

This is the error it gives me:

```
IndexError Traceback (most recent call last)
<ipython-input-1-d6ba25f80b3f> in <module>()
19 lista = [0,9,7,81,4,5,68,3,541]
20 k = len(lista[1:])
---> 21 CountingSort(lista, k)
<ipython-input-1-d6ba25f80b3f> in CountingSort(A, k)
9 B=CreaLista(len(A)-1)
10 for j in range(1, len(A)):
---> 11 C[A[j]] = C[A[j]]+1
12 for i in range(1, k+1):
13 C[i]=C[i]+C[i-1]
IndexError: list index out of range
```

## Answer:

In Python, lists start with 0. In your case, in the first iteration of the first for, `A[j]`

equal to 9. C only has 9 elements, so you could only access up to `C[8]`

. In any case, I recommend that you use the enumerate function instead of using range. The for loops would be much cleaner:

```
for key, value in enumerate(A):
pass
```