如何用python输出第一列内容相同所在的行

Question

一个txt文档有四列，如何提取第四列内容相同的所在的行
例如
1 2 4 a
4 5 6 a
1 8 9 a
8 4 5 b
期望输出
1 2 4 a
4 5 6 a
1 8 9 a

Answer 1

import itertools as it

with open("test.txt") as f:
   content = [i.strip() for i in f]
   content.sort(key = lambda x: x[-1])
   res = it.groupby(content, key = lambda x: x[-1])
   for i, v in res:
      v1 = list(v)
      if len(v1) > 1:
         print(v1)