Python: search longest palindromes within a word and palindromes within a word/string

Question

So here is a code i have written to find palindromes within a word (To check if there are palindromes within a word including the word itself) Condition: spaces inbetween ch

Answer 1

Here is another clean and simple approach taken from the excellent online course Design of Computer Programs by P. Norvig. It iterates over all characters in the string and attempts to "grow" the string to both left and right.

def longest_sub_palindrome_slice(text):
    "Return (i,j) such that text[i,j] is the longest palindrome in text"
    if text == '': return (0, 0)
    def length(slice): a,b = slice; return b-a
    candidates = [grow(text, start, end)
                 for start in range(len(text))
                 for end in (start, start + 1)]
    return max(candidates, key=length)

def grow(text, start, end):
    "Start with a 0- or 1- length palindrome; try to grow a bigger one"
    while (start > 0 and end < len(text)
           and text[start-1].upper() == text[end].upper()):
        start -= 1; end += 1
    return (start, end)