Why does my palindrome checker doesn't find any result?

June 30, 2022

words = ['Anna', 'Alexey', 'Alla', 'Kazak', 'Dom']

def palindrome():
    filtered_2 = list(filter(lambda x: x == x[::-1], words))
    print(filtered_2)

palindrome()

The code should return palindrome words, but it gives me an output like this:

[]

It should give:

['Anna', 'Alla', 'Kazak']

>Solution :

You need to normalize the input before comparisons. Basically you are checking if 'A' == 'a' which will fail.

Try this example where I normalize to lowercase using str.lower():

words = ['Anna', 'alexey', 'Alla', 'kazak', 'dom']

def palindrome():
    filtered_2 = list(filter(lambda x: x.lower() == x.lower()[::-1], words))
    print(filtered_2)

palindrome()