Python 根據name獲得name下的最小時間

想根據名稱來獲得這個名稱下的最小時間

#! /usr/bin/env python
# -*- coding:utf-8 -*-
m = ['20181008','20181009']
t = [['201801', '20181008', 'actual'], ['201841', '20181008', 'forecast'],
     ['201842', '20181009', 'forecast'], ['201843', '20181009', 'forecast'],
     ['201844', '20181008', 'forecast'], ['201845', '20181008', 'forecast'],
     ['201845', '20181007', 'forecast']]

for x in range(0,len(m)):
    n = []
    n_new = []
    i = 0
    while i<len(t):
        if t[i][1] == m[x]:
            n.append([t[i][0],t[i][2]])
        i+=1
    n_new = sorted(list(n))
    print n_new[0]

輸出結果爲：

['201801', 'actual']
['201842', 'forecast']