longest palindromic substring

__init__.py

''' longest_palindromic_substring package '''

longest_palindromic_substring.py

''' longest_palindromic_substring finds the longest palindrome substring in a string
'''


def lpss(s):
    ''' lpss (Longest Palindromic SubString) returns the longest palindrome withing the string

    Args:
        s (str): string to search

    Returns:
        str: resultant substring; the first longest palindromic substring
    '''
    len_s = len(s)
    l_pal = ''
    for j in range(1, len_s+1):
        for i in range(len_s - j+1):
            ss = s[i:i+j]
            if ss == ss[::-1] and len(ss) > len(l_pal):
                l_pal = ss

    return l_pal

test_longest_palindromic_substring.py

''' test_longest_palindromic_substring tests the longest_palindromic_substring module
'''

from .longest_palindromic_substring import lpss


def test_lpss():
    cases = [
        ('These are not the droids you\'re looking for.', 'ese'),
        ('Ugh, no palindromes!', 'U'),
        ('racecar', 'racecar'),
        ('bananarama', 'anana'),
        ('A but tuba.', 'but tub'),
        ('My mom did eat a pip.', ' mom '),
    ]
    for s, want in cases:
        got = lpss(s)
        assert want == got, 'incorrect palindrome - want: {0}, got: {1}'.format(want, got)