如何将矢量a<-c(1,2,3,4,5,6)置于矩阵m<-matrix(0, nrow = 10, ncol = 10)中的ramdom位置？
载体必须在一起：
[,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
它必须是水平，垂直或对角线 我试过了：
start = sample.int(length(m), 1)
m[start:(start+length(a)-1)] = a
但不能发生以下情况：
[,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
由于
答案 0 :(得分：1)
采样与a大小相同的1d索引，然后在这些索引处将矢量分配给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
如果向量需要是连续的，您可以对起始索引进行采样，然后使用范围索引进行分配：
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