# R in Action (2nd ed): Chapter 6
# Basic graphs
# requires packages vcd, plotrix, sm, vioplot to be installed
install.packages(c("vcd", "plotrix", "sm", "vioplot"))
#------------------------------------------------------------

# kernel density plot
install.packages("sm")

par(mfrow=c(2,1))
?par

# par function with mfrow option to figures to be arranged accordingly, in this case 2 lines one column # <- coment 1

d <- density(mtcars$mpg) # returns the density data  
plot(d) # plots the results 


d <- density(mtcars$mpg)                                  
plot(d, main="Kernel Density of Miles Per Gallon")       
polygon(d, col="red", border="blue")                     
rug(mtcars$mpg, col="brown") 

par(lwd=2)                                                       
library(sm)
attach(mtcars)

# create value labels 
cyl.f <- factor(cyl, levels= c(4, 6, 8),                               
                labels = c("4 cylinder", "6 cylinder", "8 cylinder")) 

cyl.f
head(cyl.f)
tail(cyl.f)
summary(cyl.f)

# plot densities 
sm.density.compare(mpg, cyl, xlab="Miles Per Gallon")                
title(main="MPG Distribution by Car Cylinders")

# add legend via mouse click
colfill<-c(2:(2+length(levels(cyl.f)))) 
cat("Use mouse to place legend...","\n\n")
legend(locator(1), levels(cyl.f), fill=colfill) 
detach(mtcars)
par(lwd=1)



# box plots
boxplot(mtcars$mpg, main="Box plot", ylab="Miles per Gallon")

mtcars

boxplot.stats(mtcars$mpg)

# parallel box plots
boxplot(mpg~cyl,data=mtcars,
        main="Car Milage Data", 
        xlab="Number of Cylinders", 
        ylab="Miles Per Gallon")


# notched box plots
boxplot(mpg~cyl,data=mtcars, 
        notch=TRUE, 
        varwidth=TRUE,
        col="red",
        main="Car Mileage Data", 
        xlab="Number of Cylinders", 
        ylab="Miles Per Gallon")


# create a factor for number of cylinders
mtcars$cyl.f <- factor(mtcars$cyl,
                       levels=c(4,6,8),
                       labels=c("4","6","8"))
# create a factor for transmission type
mtcars$am.f <- factor(mtcars$am, 
                      levels=c(0,1), 
                      labels=c("auto","standard"))

# generate boxplot
boxplot(mpg ~ am.f *cyl.f, 
        data=mtcars, 
        varwidth=TRUE,
        col=c("gold", "darkgreen"),
        main="MPG Distribution by Auto Type", 
        xlab="Auto Type")


#VIOLIN PLOTS
library(vioplot)
x1 <- mtcars$mpg[mtcars$cyl==4] 
x2 <- mtcars$mpg[mtcars$cyl==6]
x3 <- mtcars$mpg[mtcars$cyl==8]

vioplot(x1, x2, x3, 
        names=c("4 cyl", "6 cyl", "8 cyl"), col="gold")
title("Violin Plots of Miles Per Gallon", ylab="Miles Per Gallon", xlab="Number of Cylinders")