read.table("heptathlon.txt",header=TRUE)->hept
# http://cran.r-project.org/web/packages/HSAUR/vignettes/Ch_principal_components_analysis.pdf

library(HSAUR)
plot(heptathlon)
ht<-heptathlon[,-8]
plot(ht)

htpca<-princomp(ht,cor=TRUE)
htpca2<-princomp(ht)
summary(htpca)

loadings(htpca)

?scale
par(mfrow=c(1,2))
biplot(htpca)
biplot(htpca2)


#abline(h=0,v=0,lty=2)
#ht2<-ht
#ht2$hurdles<-max(ht2$hurdles)-ht2$hurdles
#ht2$run200m<-max(ht2$run200m)-ht2$run200m
#ht2$run800m<-max(ht2$run800m)-ht2$run800m

#plot(ht2)
#loadings(pc2<-princomp(ht2,cor=T))
#summary(pc2)
#biplot(pc2)

str(htpca)
htpca$scores[,1]

#par(mfrow=c(1,2))
#biplot(htpca)
#biplot(pc2)
#ht_pca <- prcomp(ht, scale=TRUE)
#summary(ht_pca)


a1<-htpca$loadings[,1]
a1
a2<-htpca$loadings[,2]
a2

plot(htpca$scores[,1],heptathlon$score,col=rainbow(25),pch=16)
plot(htpca$scores[,2],heptathlon$score,col=rainbow(25),pch=16)