Project Euler: Largest palindrome (Python). What did I do wrong?

Question

I may have done many things wrong as I am only a beginner. But would someone please help me? The goal is to print the largest palindrome made from the product of two 3-digit numbers. Thanks.

palindromes = []
for i in range(100, 1000):
    for x in range(100, 1000):
        a = x*i
        str(a)
        b = a[::-1]
        if a == b :
            palindromes.append(a)

print (palindromes[len(palindromes) - 1])

Answer 1

Basic points:

• When you convert the number to a string, you have to store the result.
• Sort the list when you're done.
• Use right-end indexing to get the last element
• When you find a palindrome, keep the integer form, so the sort works properly. Otherwise, you get '99999' as the largest palindrome.

Code:

palindromes = []
for i in range(100, 1000):
    for x in range(100, 1000):
        a = str(x*i)
        b = a[::-1]
        if a == b :
            palindromes.append(int(a))

print (sorted(palindromes)[-1])