我有一个矩阵X
:
one two three four
[1,] 1 3 2 4
[2,] 2 0 1 5
[3,] 3 2 1 4
[4,] 4 9 11 19
[5,] 4 3 2 1
我想得到一个新的矩阵Y
,它只包含"1"、"2"、"3"、"4"的排列.即:
one two three four
[1,] 1 3 2 4
[3,] 3 2 1 4
[5,] 4 3 2 1
我应该使用什么函数或命令?