第一个用 sample(5)
,后面两个用sample(6, size = 5)
或者先把data.frame
用cbind()
连起来,然后用cbind(sample(5), sample(6:11, size = 5), sample(12:17, size = 5))
抽样,再用apply()
或者循环取子集
> cbind(sample(5), sample(6:11, size = 5), sample(12:17, size = 5))
[,1] [,2] [,3]
[1,] 3 6 13
[2,] 2 8 16
[3,] 5 9 17
[4,] 1 10 15
[5,] 4 7 14