r - R中矩阵列表的元素中位数

Question

给定一个矩阵列表:

temp <- list(matrix(c(1,8,3,400), 2), 
    matrix(c(5,2,300,14),2), 
    matrix(c(100,200,12,4),2)
)
temp
# [[1]]
#      [,1] [,2]
# [1,]    1    3
# [2,]    8  400
#
# [[2]]
#      [,1] [,2]
# [1,]    5  300
# [2,]    2   14
#
# [[3]]
#      [,1] [,2]
# [1,]  100   12
# [2,]  200    4

我想要矩阵的元素中位数:

     [,1] [,2]
[1,]    5   12
[2,]    8   14

这可以在没有显式 for 循环的情况下完成吗？

Answer 1

首先，把它放入一个数组中:

library(abind)
a <- do.call(abind, c(temp, list(along=3)))

然后使用应用:

apply(a, 1:2, median)
#      [,1] [,2]
# [1,]    5   12
# [2,]    8   14

---

正如@RichardScriven 建议的那样，您也可以在没有 abind 包的情况下构建 a:

a <- array(unlist(temp), c(2, 2, 3))
# or
a <- array(unlist(temp), c(dim(temp[[1]]), length(temp)))