sorting a matrix in r

April 5, 2023

I have a matrix like below but with n rows

rm(list=ls())
set.seed(123)
mt=as.matrix(replicate(5,sample(1:3,4,replace = TRUE)))
mt
#>      [,1] [,2] [,3] [,4] [,5]
#> [1,]    3    3    3    1    3
#> [2,]    3    2    1    2    3
#> [3,]    3    2    2    3    1
#> [4,]    2    2    2    1    1

To sort it row by row . I am using this code with the order function like here

od2=order(mt[1,],mt[2,],mt[3,],mt[4,])
mt[,od2]
#>      [,1] [,2] [,3] [,4] [,5]
#> [1,]    1    3    3    3    3
#> [2,]    2    1    2    3    3
#> [3,]    3    2    2    1    3
#> [4,]    1    2    2    1    2

is there any way to have an adapted one for n multiple rows. I wasn’t successful with the second version of @Joshua Ulrich code in the comment. I am not familiar with do.call function

^{Created on 2023-04-05 with reprex v2.0.2}

>Solution :

You can use asplit:

mt[,do.call(order, asplit(mt, 1))]
#     [,1] [,2] [,3] [,4] [,5]
#[1,]    1    3    3    3    3
#[2,]    2    1    2    3    3
#[3,]    3    2    2    1    3
#[4,]    1    2    2    1    2