#lattice
library(lattice)
data <- read.table("data.txt",header=T)
jpeg("multi_lattice.jpg")
barchart(data$Num~data$Class|data$Group)
dev.off()

#matrix
data <- read.table("data.txt",header=T)
jpeg("multi_matrix.jpg")
layout(matrix(1:4, 2, 2,byrow=T))
barplot(data[data[,1]=="A",]$Num,main="A",col="lightblue",names.arg=c("X","Y"))
barplot(data[data[,1]=="B",]$Num,main="B",col="lightblue",names.arg=c("X","Y"))
barplot(data[data[,1]=="C",]$Num,main="C",col="lightblue",names.arg=c("X","Y"))
barplot(data[data[,1]=="D",]$Num,main="D",col="lightblue",names.arg=c("X","Y"))
#for(i in levels(as.factor(data$Group))){
#barplot(data[data[,1]==i,]$Num,main=i,col="lightblue",names.arg=c("X","Y"))
#}
dev.off()