从r中的vector创建一个复杂的矩阵

时间:2016-08-03 10:42:42

标签: r vector rep

我有4个种群的样本量矢量:3 2 1 4,总计10个人。我需要动态的代码(因此可以在不同的情况下使用)制作一个1和0的矩阵,其中10行和4列具有3 1,然后该列的其余部分为0,然后下一列有3 0然后2 1然后剩下的0,依此类推如下:

1 0 0 0
1 0 0 0
1 0 0 0
0 1 0 0
0 1 0 0
0 0 1 0
0 0 0 1
0 0 0 1
0 0 0 1
0 0 0 1

输入:

nSamples <- c(3,2,1,4)

3 个答案:

答案 0 :(得分:3)

这是一个可能的两步法。

# create a matrix of zeros first
m <- matrix(0L, ncol = length(nSamples), nrow = sum(nSamples))
# then replace relevant 0s with 1s:
m[cbind(1:nrow(m), rep(seq_along(nSamples), nSamples))] <- 1L
m
#      [,1] [,2] [,3] [,4]
# [1,]    1    0    0    0
# [2,]    1    0    0    0
# [3,]    1    0    0    0
# [4,]    0    1    0    0
# [5,]    0    1    0    0
# [6,]    0    0    1    0
# [7,]    0    0    0    1
# [8,]    0    0    0    1
# [9,]    0    0    0    1
# [10,]   0    0    0    1

&#34;技巧&#34;,如果你愿意,

rep(seq_along(nSamples), nSamples)
#[1] 1 1 1 2 2 3 4 4 4 4

答案 1 :(得分:1)

您可以使用model.matrix

创建设计矩阵
f_nSamples <- factor(rep(nSamples, nSamples), orderd=TRUE)
model.matrix(~f_nSamples-1)
##    f_nSamples1 f_nSamples2 f_nSamples3 f_nSamples4
## 1            1           0           0           0
## 2            1           0           0           0
## 3            1           0           0           0
## 4            0           1           0           0
## 5            0           1           0           0
## 6            0           0           1           0
## 7            0           0           0           1
## 8            0           0           0           1
## 9            0           0           0           1
## 10           0           0           0           1
## attr(,"assign")
## [1] 1 1 1 1
## attr(,"contrasts")
## attr(,"contrasts")$f_nSamples
## [1] "contr.treatment"

答案 2 :(得分:1)

以下是sparseMatrix

的单行
library(Matrix)
m1 <- sparseMatrix(i = seq(sum(nSamples)), j = rep(seq_along(nSamples), nSamples), x = 1)
as.matrix(m1)
#      [,1] [,2] [,3] [,4]
#[1,]    1    0    0    0
#[2,]    1    0    0    0
#[3,]    1    0    0    0
#[4,]    0    1    0    0
#[5,]    0    1    0    0
#[6,]    0    0    1    0
#[7,]    0    0    0    1
#[8,]    0    0    0    1
#[9,]    0    0    0    1
#[10,]   0    0    0    1