Question

如果我有一个矩阵说：

> mat1=matrix(1:12, ncol=3)
> mat1
     [,1] [,2] [,3]
[1,]    1    5    9
[2,]    2    6   10
[3,]    3    7   11
[4,]    4    8   12

如何复制每一列并将其放在原始列旁边，这样看起来像这样：

     [,1] [,2] [,3] [,4] [,5] [,6]
[1,]    1    1    5    5    9    9    
[2,]    2    2    6    6   10   10
[3,]    3    3    7    7   11   11
[4,]    4    4    8    8   12   12

我确信这很简单但看不到它！非常感谢。

Answer 1

试试这个：

mat1=matrix(1:12, ncol=3)
mat1[,rep(1:ncol(mat1),each=2)]
##      [,1] [,2] [,3] [,4] [,5] [,6]
## [1,]    1    1    5    5    9    9
## [2,]    2    2    6    6   10   10
## [3,]    3    3    7    7   11   11
## [4,]    4    4    8    8   12   12

Answer 2

可能最容易重新订购一个简单的cbind：

cbind(mat, mat)[,order(rep(1:ncol(mat), times=2))]

或

mat[,rep(1:ncol(mat), each=2)]

重复矩阵列并放在R中的原始列旁边

2 个答案: