返回列表中最长的连续字符串

题目描述：

　　

# 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 "".


我的解答：
　　

def consecutive_string(lis, k):
    result = ''
    if k > 0 and len(lis) >= k:
        for i in range(len(lis) - k + 1):
            s = ''.join(lis[i:i + k])
            if len(s) > len(result):
                result = s
    return result