pairs.panels: SPLOM, histograms and correlations for a data matrix

Description

Adapted from the help page for pairs, pairs.panels shows a scatter plot of matrices (SPLOM), with bivariate scatter plots below the diagonal, histograms on the diagonal, and the Pearson correlation above the diagonal. Useful for descriptive statistics of small data sets.

Usage

pairs.panels(x, y, smooth = TRUE, scale = FALSE, digits = 2, ...)

Arguments

a data.frame or matrix

an optional data.frame or matrix

smooth

TRUE draws loess smooths

scale

TRUE scales the correlation font by the size of the absolute correlation.

digits

the number of digits to show

...

other options for pairs

Value

a scatter plot matrix (SPLOM) is drawn in the graphic window. The lower off diagonal draws scatter plots, the diagonal histograms, the upper off diagonal reports the Pearson correlation (with pairwise deletion).

Details

Shamelessly adapted from the pairs help page. Uses panel.cor, panel.cor.scale, and panel.hist, all taken from the help pages for pairs.

Examples

Run this code

#pairs.panels(attitude)   #see the graphics window

## The function is currently defined as
function (x, y, smooth = TRUE, scale = FALSE, digits = 2, ...) 
{
    if (smooth) {
        if (scale) {
            pairs(x, diag.panel = panel.hist, upper.panel = panel.cor.scale, 
                lower.panel = panel.smooth, ...)
        }
        else {
            pairs(x, diag.panel = panel.hist, upper.panel = panel.cor, 
                lower.panel = panel.smooth, ...)
        }
    }
    else {
        if (scale) {
            pairs(x, diag.panel = panel.hist, upper.panel = panel.cor.scale, 
                ...)
        }
        else {
            pairs(x, diag.panel = panel.hist, upper.panel = panel.cor, 
                ...)
        }
    }
  }
  
  #
  ## The function is currently defined as
"panel.cor" 
function(x, y, digits=2, prefix="", cex.cor)
     {
         usr <- par("usr"); on.exit(par(usr))
         par(usr = c(0, 1, 0, 1))
         r = (cor(x, y,use="pairwise"))
         txt <- format(c(round(r,digits), 0.123456789), digits=digits)[1]
         txt <- paste(prefix, txt, sep="")
         if(missing(cex.cor)) cex <- 0.8/strwidth(txt)
         text(0.5, 0.5, txt, cex = cex )
     }
     
 ## The function is currently defined as
 "panel.cor.scale" 
function(x, y, digits=2, prefix="", cex.cor)
     {
         usr <- par("usr"); on.exit(par(usr))
         par(usr = c(0, 1, 0, 1))
         r = (cor(x, y,use="pairwise"))
         txt <- format(c(r, 0.123456789), digits=digits)[1]
         txt <- paste(prefix, txt, sep="")
         if(missing(cex.cor)) cex <- 0.8/strwidth(txt)
         text(0.5, 0.5, txt, cex = cex * abs(r))
     }
 "panel.hist"    
 function(x, ...)
{
    usr <- par("usr"); on.exit(par(usr))
    par(usr = c(usr[1:2], 0, 1.5) )
    h <- hist(x, plot = FALSE)
    breaks <- h$breaks; nB <- length(breaks)
    y <- h$counts; y <- y/max(y)
    rect(breaks[-nB], 0, breaks[-1], y, col="cyan", ...)
  }