英文:
use lapply function to modify several matrices in R
问题
I'd like to delete one column (f.e. column 3) from several matrices that are stored in a list.
Can I do this without defining a function?
This is the approach using an own function:
m1 <- matrix(1:9, nrow = 3, ncol = 3)m2 <- matrix(1:9, nrow = 3, ncol = 3)m3 <- matrix(1:9, nrow = 3, ncol = 3)m_ls <- list(m1,m2,m3)del <- function(mat){mat <- mat[,-3]return(mat)}lapply(m_ls, del)
英文:
I'd like to delete one column (f.e. column 3) from several matrices that are stored in a list.
Can I do this without defining a function?
This is the approach using an own function:
m1 <- matrix(1:9, nrow = 3, ncol = 3)m2 <- matrix(1:9, nrow = 3, ncol = 3)m3 <- matrix(1:9, nrow = 3, ncol = 3)m_ls <- list(m1,m2,m3)del <- function(mat){mat <- mat[,-3]return(mat)}lapply(m_ls, del)
答案1
得分: 4
你可以使用[作为一个函数：
m1 <- m2 <- m3 <- matrix(1:9, nrow = 3, ncol = 3)m_ls <- list(m1, m2, m3)lapply(m_ls, `[`, , -3)#> [[1]]#> [,1] [,2]#> [1,] 1 4#> [2,] 2 5#> [3,] 3 6#>#> [[2]]#> [,1] [,2]#> [1,] 1 4#> [2,] 2 5#> [3,] 3 6#>#> [[3]]#> [,1] [,2]#> [1,] 1 4#> [2,] 2 5#> [3,] 3 6
创建于2023-06-04，使用reprex v2.0.2
英文:
You could use [ as a function:
m1 <- m2 <- m3 <- matrix(1:9, nrow = 3, ncol = 3)m_ls <- list(m1,m2,m3)lapply(m_ls, `[`, , -3)#> [[1]]#> [,1] [,2]#> [1,] 1 4#> [2,] 2 5#> [3,] 3 6#>#> [[2]]#> [,1] [,2]#> [1,] 1 4#> [2,] 2 5#> [3,] 3 6#>#> [[3]]#> [,1] [,2]#> [1,] 1 4#> [2,] 2 5#> [3,] 3 6
<sup>Created on 2023-06-04 with reprex v2.0.2</sup>
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