[Tutor] IndexError: list index out of range [ Program work fine , but gives this message , guidance requested ]

[Guillermo Fernandez Castellanos]

Hi,

Look at this:
 >>> i=[1,2,3]
 >>> i[len(i)]
Traceback (most recent call last):
   File "<stdin>", line 1, in ?
IndexError: list index out of range


This means that I have tried to access an element that is out of the 
list, in this case i[3], that is, the 4th element of the list.

You are doing the same. You do a
j in range(len(seats))
and then you are accessing your list with seats[j] and seats[j+1]. What 
happens when j = len(seats)-1 and you call seats[j+1]? :-)

It happens indeed the same that in the example I gave you first.

Hope it helps. Good luck,

G

John Joseph wrote:
> Hi All 
>       I am trying to find out the duplicates in a list
> , as for beginning I wanted to compare the  adjacent
> elements in list , for this purpose I wrote a script
> for checking the adjacent elements in a list,  if same
> , it prints the result that , the adjacent numbers are
> same , it not  it will print  adjacent numbers are
> same 
>                  My program works ,  but at the end of
> the program execution it throws error 
> 
> “Traceback (most recent call last):
>   File "arrayduplinital.py", line 27, in ?
>     if seats[j] <> seats[j+1]:
> IndexError: list index out of range”
> 
>                      I tried my best to find the logic
> , why this error is coming , I was not able to find
> the reason ,  I request your guidance for the reason
> for this error and how to avoid it 
>              I am adding the code which I wrote for
> this program
> 
> **************************************************************************************
> """
>   find duplicates in a list
>         (1) Sort the array
>         (2) counter
>                   i = 0
>                   j = 0
>         (3) for j <= length
>                 if seats[j] <> seats[j+1] ==> print
> value j and j+1 are not same
>                        else  ===>  print value j ,  j
> +1 are same
> 
> """
> 
> seats = []
> i = 0
> length  = int(raw_input("Enter The Lenght of the array
> :  "))
> 
> while i < length:
>         num = int(raw_input("Enter the Seats :  "))
>         seats.append(num)
>         i += 1
> print seats
> 
> seats.sort()
> 
> j = 0
> for j in range(length):
>         if seats[j] <> seats[j+1]:
>                 print " The Seat", j , "And the seat",
> j+1 , "value, which are", seats[j]," and", seats[j+1],
> "are not same" 
>         else:
>                 print "The Seats ",j ,"And the seats",
> j+1, "Values,", seats[j], "and", seats[j+1], "are
> same"
> ~
> 
> 
> 
> 
> 		
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