Plot of a correlation matrix in R like in Excel example

Question

I have been trying to minimize my use of Excel in favor of R, but am still stuck when it comes to display simple data cells as is often needed as the last step of an analysis. T

Answer 1

Here is an approach using base graphics:

par( mar=c(1,5,5,1) )
plot.new()
plot.window( xlim=c(0,10), ylim=c(0,11) )

quant_vals <- findInterval( cor_matrix[-11,], 
    c(-Inf, quantile(cor_matrix[-11,], c(0.05, 0.25, 0.45, 0.55, 0.75, 0.95), na.rm=TRUE ),
            Inf) )
quant_vals[ is.na(quant_vals) ] <- 4
cols <- c('#ff0000','#ff6666','#ffaaaa','#ffffff','#aaffaa','#66ff66','#00ff00')
colmat <- matrix( cols[quant_vals], ncol=10, nrow=10)

rasterImage(colmat, 0, 1, 10, 11, interpolate=FALSE)
for(i in seq_along( cor_matrix[11,] ) ) {
    rect( i-1, 0.1, i-1 + cor_matrix[11,i]/max(cor_matrix[11,]), 0.9, col='lightsteelblue3')
}

text( col( cor_matrix )-0.5, 11.5-row( cor_matrix ), cor_matrix, font=2 )
rect( 0,1,10,11 )
rect( 0,0,10,1)
axis(2, at=(11:1)-0.5, labels=rownames(cor_matrix), tick=FALSE, las=2)
axis(3, at=(1:10)-0.5, labels=colnames(cor_matrix), tick=FALSE, las=2)

rect(0,8,3,11, lwd=2)
rect(4,4,7,7, lwd=2)
rect(8,1,10,3, lwd=2)