https://www.codewars.com/kata/consecutive-strings/train/python

Task

You are given an array strarr of strings and an integer k. Your task is to return the first longest string consisting of k consecutive strings taken in the array.

Example:

longest_consec(["zone", "abigail", "theta", "form", "libe", "zas", "theta", "abigail"], 2) --> "abigailtheta"

n being the length of the string array, if n = 0 or k > n or k <= 0 return "".

Best Practices

Py First:

def longest_consec(strarr, k):
    result = ""

    if k > 0 and len(strarr) >= k:
        for index in range(len(strarr) - k + 1):
            s = ''.join(strarr[index:index+k])
            if len(s) > len(result):
                result = s

    return result

Py Second:

def longest_consec(s, k):
    return max(["".join(s[i:i+k]) for i in range(len(s)-k+1)], key=len) if s and 0 < k <= len(s) else ""

Py Third:

def longest_consec(strarr, k):
    if (len(strarr) == 0 or k <= 0) or len(strarr) < k:
        return ""
    lst = [''.join(strarr[i:i+k]) for i in xrange(len(strarr))]
    return max(lst, key= lambda x: len(x))