在R中的矩阵内随机放置一个向量

Question

如何将向量a<-c(1,2,3,4,5,6) 放置在矩阵m<-matrix(0, nrow = 10, ncol = 10) 中的随机位置？

向量必须在一起：

       [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
 [1,]    0    0    0    0    0    0    0    0    0     0
 [2,]    1    0    0    0    0    0    0    0    0     0
 [3,]    2    0    0    0    0    0    0    0    0     0
 [4,]    3    0    0    0    0    0    0    0    0     0
 [5,]    4    0    0    0    0    0    0    0    0     0
 [6,]    5    0    0    0    0    0    0    0    0     0
 [7,]    6    0    0    0    0    0    0    0    0     0
 [8,]    0    0    0    0    0    0    0    0    0     0
 [9,]    0    0    0    0    0    0    0    0    0     0
[10,]    0    0    0    0    0    0    0    0    0     0

而且它必须是水平的、垂直的或对角的 我试过了：

start = sample.int(length(m), 1)
m[start:(start+length(a)-1)] = a

但它不能发生以下情况：

       [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
 [1,]    0    0    0    0    0    0    5    0    0     0
 [2,]    0    0    0    0    0    0    6    0    0     0
 [3,]    0    0    0    0    0    0    0    0    0     0
 [4,]    0    0    0    0    0    0    0    0    0     0
 [5,]    0    0    0    0    0    0    0    0    0     0
 [6,]    0    0    0    0    0    0    0    0    0     0
 [7,]    0    0    0    0    0    1    0    0    0     0
 [8,]    0    0    0    0    0    2    0    0    0     0
 [9,]    0    0    0    0    0    3    0    0    0     0
[10,]    0    0    0    0    0    4    0    0    0     0

谢谢

Answer 1

对与a 大小相同的一维索引进行采样，然后在这些索引处将向量分配给m：

m[sample.int(length(m), length(a))] <- a
m
#      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
# [1,]    0    6    0    0    0    0    0    0    0     0
# [2,]    0    0    0    0    0    4    0    0    0     0
# [3,]    0    3    0    1    0    0    0    0    5     0
# [4,]    0    0    0    0    0    0    0    0    0     0
# [5,]    0    0    0    0    0    0    0    0    0     0
# [6,]    0    0    0    0    0    0    0    0    0     0
# [7,]    0    0    0    0    0    0    0    0    0     0
# [8,]    0    0    0    0    0    0    0    0    2     0
# [9,]    0    0    0    0    0    0    0    0    0     0
#[10,]    0    0    0    0    0    0    0    0    0     0

---

如果向量需要连续，可以采样起始索引，然后用范围索引赋值：

start = sample.int(length(m), 1)
m[start:(start+length(a)-1)] = a

m
#      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
# [1,]    0    0    0    0    0    0    0    0    0     0
# [2,]    0    0    0    0    0    0    0    0    0     0
# [3,]    0    0    0    0    0    0    0    0    0     0
# [4,]    0    0    0    0    0    0    0    0    0     0
# [5,]    1    0    0    0    0    0    0    0    0     0
# [6,]    2    0    0    0    0    0    0    0    0     0
# [7,]    3    0    0    0    0    0    0    0    0     0
# [8,]    4    0    0    0    0    0    0    0    0     0
# [9,]    5    0    0    0    0    0    0    0    0     0
#[10,]    6    0    0    0    0    0    0    0    0     0