R语言实战

> dotchart(mtcars$mpg, labels=row.names(mtcars), cex=.7,
+         main="Gas Mileage for Car Models",
+         xlab="Miles Per Gallon")
> 

> x <- mtcars[order(mtcars$mpg),]
> x$cyl <- factor(x$cyl)
> x$color[x$cyl==4] <- "red"
> x$color[x$cyl==6] <- "blue"
> x$color[x$cyl==8] <- "darkgreen"
> dotchart(x$mpg,
+          labels=row.names(x),
+          cex=.7,
+          groups=x$cyl,
+          gcolor="black",
+          color=x$color,
+          pch=19,
+          main="Gas Mileage for Car Models
grouped by cylinder",
+          xlab="Miles Per Gallon")
>