Question

This code should print the sum of the even numbers in the first ten numbers of the Fibonacci sequence.

#Creates a list with the first ten Fibonacci numbers. 
l = [1,2]
for i in range(10):
    l.append(l[i]+l[i+1])

for i in l:
    #If an element of the Fibonacci list is uneven, replace it with zero.
    if l[i]%2 != 0:
        l[i] = 0

#Print the sum of the list with all even Fibonacci numbers. 
print sum(l)

When I execute this I get:

  File "pe2m.py", line 6, in <module>
    if l[i]%2 != 0:
IndexError: list index out of range

I don’t get how its going out of range, could someone clarify?

Answer 1

You are looping over the values not the index positions!

Use the following code instead:

#Creates a list with the first ten Fibonacci numbers. 
l = [1,2]
for i in range(10):
    l.append(l[i]+l[i+1])

for i in range(len(l)):
    #If an element of the Fibonacci list is uneven, replace it with zero.
    if l[i]%2 != 0:
        l[i] = 0

#Print the sum of the list with all even Fibonacci numbers. 
print sum(l)