user2957945 user2957945 - 2 months ago 21
R Question

Print method for multiple matrices

Could someone please suggest a method to

print
several matrices side by side in the terminal window.

For the matrices
m1
and
m2
, I would like the desired output below.

m1 <- m2 <- matrix(1:4, nrow=2, dimnames=list(c("a", "b"), c("d", "e")))


Desired output

m1 m2
d e d e
a 1 3 a 1 3
b 2 4 b 2 4


The reason is that I have several 2x2 matrices that i am using in calculations and want to show in a Rmarkdown doc. It takes up a bit too much of the page when printing length ways. Thanks.

EDIT

My attempt at a solution

fn <- function(x) setNames(data.frame(.=paste(" ", rownames(x)), x,
check.names=F, row.names=NULL),c(paste(substitute(x)), colnames(x)))
cbind(fn(m1), fn(m2))
# m1 d e m2 f g
#1 a 1 3 v 1 3
#2 b 2 4 w 2 4


But this of course doesnt look very good.

Answer

A little hack-ish, but I believe it is what you want:

m1 <- m2 <- m3 <- m4 <- matrix(1:4, nrow=2, dimnames=list(c("a", "b"), c("d", "e")))
fn <- function(x) setNames(data.frame(.=paste("", rownames(x)), x, check.names=F, row.names=NULL),c(" ", colnames(x)))
matrix.names <- Filter( function(x) 'matrix' %in% class( get(x) ), ls(pattern = "m") )
matrix.list <- lapply(matrix.names, get)
matrix.chain <- do.call(cbind, lapply(matrix.list, fn))
cat(" ", paste0(matrix.names, collapse = "     "), "\n"); print(matrix.chain, row.names = FALSE)
  m1     m2     m3     m4 
    d e    d e    d e    d e
  a 1 3  a 1 3  a 1 3  a 1 3
  b 2 4  b 2 4  b 2 4  b 2 4