def is_palin_iterative_from_recursive(s):
    """
    I created this version by transforming the recursive solution to
    an iterative one. In my tests its a bit faster then `is_plain_strrec`
    """
    s  = str(s)
    while True:
        if not s:
            return True
        elif s[0] != s[-1]:
            return False
        else:
            s = s[1:-1]

def is_palin_iterative_with_while(s):
    """
    Like the iterative version, but uses a while loop
    and thus avoids some of the overhead in the for-loop version
    """
    s  = str(s)
    i = 0
    t = len(s) // 2
    while i < t:
        if s[i] != s[-(1+i)]:
            return False
        i += 1
    return True