我寻找一个R-代码来转换矩阵如下(a:原始矩阵,b:期望的输出),例如:
a <- matrix(c(1,2,3,4,5,6,1,2,3,4,5,6,1,2,3,4,5,6,1,2,3,4,5,6), nrow = 6, ncol = 4)
b <- matrix(c(1,2,3,4,5,6,2,3,4,5,6,0,3,4,5,6,0,0,4,5,6,0,0,0), nrow = 6, ncol = 4)
a
[,1] [,2] [,3] [,4]
[1,] 1 1 1 1
[2,] 2 2 2 2
[3,]