R return corrplot as object

Question

corrplot plots a correlation matrix, but it does not return a graphical object (grob)

I would like to plot several correlation matrices on a single page. For normal plots, I would use grid.arrange from the gridExtra package. However since corrplot only prints and does not return an object, I can't see how to do this.

Is there a workaround or a better alternative to corrplot ?

Answer 1

There's the old standby par(mfrow=c(x, y)) where x is the number of rows you wish to plot and y the numberof columns. It then posts across and then down as you call the plots.

par(mfrow = c(2, 2))
corrplot(cor(mat1))
corrplot(cor(mat2))
corrplot(cor(mat3))
corrplot(cor(mat4))

par(mfrow = c(1, 1)) #To clear layout

Will plot as

Mat1 | Mat2
-----------
Mat3 | Mat4

Answer 2

The recent gridGraphics package could probably do what you asked: return the plot as a grob.

mat <- matrix(rnorm(100), ncol=10)
library(corrplot)
corrplot(cor(mat))

library(gridGraphics)
grab_grob <- function(){
  grid.echo()
  grid.grab()
}

g <- grab_grob()
library(gridExtra)
grid.newpage()
grid.arrange(g,g,g,g)

Answer 3

Not sure if I got your question right, but maybe what you are looking for is simple layout ?

mat <- matrix(rnorm(100), ncol=10)

layout(matrix(1:2))
corrplot(cor(mat))
corrplot(cor(mat))