Why do I get ‘IndexError: list index out of …

I get this error:

IndexError: list index out of range

This is my function:

def power(x, y, bound):
    list, exp = [], []
    z = -1
    for i in range (1, bound):
        for j in range (1, bound):
            if x**i + y**j in range (bound):
                if x**i + y**j in list:
                    break
                else:
                    list.append(x**i + y**j)
                    z += 1
                    if z == 0:
                        exp.append(str(x**i + y**j)+" = " + str(x) + "^" + str(i) + " + " + str(y) + "^" + str(j))
                        break
                    if list[z] == max(list):
                        exp.append(str(x**i + y**j)+" = " + str(x) + "^" + str(i) + " + " + str(y) + "^" + str(j))
                    else:
                        for n in range(len(list)):
                            if (list[z] < list[n+1]) and (list[z] > list[n]):
                                exp.insert(n, str(x**i + y**j) + " = " + str(x) + "^" + str(i) + " + " + str(y) + "^" + str(j))
            else:
                break
    print("nThe list of values:", sorted(list))
    print("nExplaination:n"+"n".join(exp))

Call my function:

print("Input: Two positive integers x and y and the boundnOutput: A list of values x^i + y^j bounded by boundn(i and j are positive integers)n")
x = int(input("Input x: "))
y = int(input("Input y: "))
bound = int(input("Input the bound: "))

power(x, y, bound)

How can I solve this problem?

Answer

Ok, so now you’ve changed your code and my previous answer has been invalidated.

Now your problem is here:

if (list[z] < list[n+1]) and (list[z] > list[n]):

with n+1 because n comes from for n in range(len(list)): and eventually n+1 will fall off the end of list.

You have to ask yourself what: if (list[z] < list[n+1]) and (list[z] > list[n]): actually means.

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Answer