我试图将矩阵列表放到一个列表中,然后在每个列表中进行求和。下面是简单的代码示例:
假设我有4个矩阵:
x1 <- matrix(1:9, nrow = 3)
x2 <- matrix(2:10, nrow = 3)
x3 <- matrix(3:11, nrow = 3)
x4 <- matrix(4:12, nrow = 3)
我想将它们放入list()
中,如下所示:
[[1]]
[[1]][[1]]
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
[[1]][[2]]
[,1] [,2] [,3]
[1,] 2 5 8
[2,] 3 6 9
[3,] 4 7 10
[[2]]
[,1] [,2] [,3]
[1,] 3 6 9
[2,] 4 7 10
[3,] 5 8 11
[[3]]
[,1] [,2] [,3]
[1,] 4 7 10
[2,] 5 8 11
[3,] 6 9 12
如何对list()
中的每个元素求和?
例如,我想要的输出如下:
[[1]]
[,1] [,2] [,3]
[1,] 3 9 15
[2,] 5 11 17
[3,] 7 13 19
[[2]]
[,1] [,2] [,3]
[1,] 3 6 9
[2,] 4 7 10
[3,] 5 8 11
[[3]]
[,1] [,2] [,3]
[1,] 4 7 10
[2,] 5 8 11
[3,] 6 9 12
我尝试使用list(Reduce(`+`, x))
,但是它不起作用。
答案 0 :(得分:2)
由于要保留顶级列表,请使用lapply
:
lapply(x, function(l) if(is.list(l)) Reduce(`+`, l) else l)
#[[1]]
# [,1] [,2] [,3]
#[1,] 3 9 15
#[2,] 5 11 17
#[3,] 7 13 19
#[[2]]
# [,1] [,2] [,3]
#[1,] 3 6 9
#[2,] 4 7 10
#[3,] 5 8 11
#[[3]]
# [,1] [,2] [,3]
#[1,] 4 7 10
#[2,] 5 8 11
#[3,] 6 9 12
答案 1 :(得分:1)
@RonakShah 的相应purrr
版本,答案为map_if()
:
library(purrr)
map_if(x, is.list, reduce, `+`)
# [[1]]
# [,1] [,2] [,3]
# [1,] 3 9 15
# [2,] 5 11 17
# [3,] 7 13 19
#
# [[2]]
# [,1] [,2] [,3]
# [1,] 3 6 9
# [2,] 4 7 10
# [3,] 5 8 11
#
# [[3]]
# [,1] [,2] [,3]
# [1,] 4 7 10
# [2,] 5 8 11
# [3,] 6 9 12