python无法输入最后一行并输出

Question

我想输入：
1 2 3
4 5 6
7 8 9
然后转化为一个矩阵mat，但每次运行结果都少了最后一行‘7 8 9’，请问是什么原因呢？
代码如下

import sys
mat = []

while 1:
    try:
        line = sys.stdin.readline().split()
        row = list(map(int, line))  # [1, 2, 3]
        mat.append(row)  # 形成矩阵
        print(mat)
    except EOFError:
        print('break')
        break

结果如下：

Answer 1

>>> import sys
>>> mat = []
>>>
>>> while 1:
...     try:
...         line = sys.stdin.readline().split()
...         row = list(map(int, line))  # [1, 2, 3]
...         mat.append(row)  # 形成矩阵
...         print(mat)
...     except EOFError:
...         print('break')
...         break
...
1 2 3
[[1, 2, 3]]
4 5 6
[[1, 2, 3], [4, 5, 6]]
7 8 9
[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
[[1, 2, 3], [4, 5, 6], [7, 8, 9], []]
Traceback (most recent call last):
  File "<stdin>", line 6, in <module>
KeyboardInterrupt