Graphics Reference

Using demo/examples as a reference guide to some graphics packages:

example("pairs")

## 
## pairs> pairs(iris[1:4], main = "Anderson's Iris Data -- 3 species",
## pairs+       pch = 21, bg = c("red", "green3", "blue")[unclass(iris$Species)])

## 
## pairs> ## formula method
## pairs> pairs(~ Fertility + Education + Catholic, data = swiss,
## pairs+       subset = Education < 20, main = "Swiss data, Education < 20")

## 
## pairs> pairs(USJudgeRatings)

## 
## pairs> ## show only lower triangle (and suppress labeling for whatever reason):
## pairs> pairs(USJudgeRatings, text.panel = NULL, upper.panel = NULL)

## 
## pairs> ## put histograms on the diagonal
## pairs> panel.hist <- function(x, ...)
## pairs+ {
## pairs+     usr <- par("usr"); on.exit(par(usr))
## pairs+     par(usr = c(usr[1:2], 0, 1.5) )
## pairs+     h <- hist(x, plot = FALSE)
## pairs+     breaks <- h$breaks; nB <- length(breaks)
## pairs+     y <- h$counts; y <- y/max(y)
## pairs+     rect(breaks[-nB], 0, breaks[-1], y, col = "cyan", ...)
## pairs+ }
## 
## pairs> pairs(USJudgeRatings[1:5], panel = panel.smooth,
## pairs+       cex = 1.5, pch = 24, bg = "light blue",
## pairs+       diag.panel = panel.hist, cex.labels = 2, font.labels = 2)

## 
## pairs> ## put (absolute) correlations on the upper panels,
## pairs> ## with size proportional to the correlations.
## pairs> panel.cor <- function(x, y, digits = 2, prefix = "", cex.cor, ...)
## pairs+ {
## pairs+     usr <- par("usr"); on.exit(par(usr))
## pairs+     par(usr = c(0, 1, 0, 1))
## pairs+     r <- abs(cor(x, y))
## pairs+     txt <- format(c(r, 0.123456789), digits = digits)[1]
## pairs+     txt <- paste0(prefix, txt)
## pairs+     if(missing(cex.cor)) cex.cor <- 0.8/strwidth(txt)
## pairs+     text(0.5, 0.5, txt, cex = cex.cor * r)
## pairs+ }
## 
## pairs> pairs(USJudgeRatings, lower.panel = panel.smooth, upper.panel = panel.cor)

## 
## pairs> pairs(iris[-5], log = "xy") # plot all variables on log scale

## 
## pairs> pairs(iris, log = 1:4, # log the first four
## pairs+       main = "Lengths and Widths in [log]", line.main=1.5, oma=c(2,2,3,2))