data(iris) 
par(mfrow=c(2,2))
PCA1<-prcomp(iris[,1:4],center = TRUE,scale. =TRUE) 
biplot(PCA1)
PCA_log <- prcomp(log(iris[,1:4]),center = TRUE,scale. =TRUE) 
biplot(PCA_log)

##
install.packages("ggfortify")
library(ggplot2)
library(ggfortify)
pca2_plot<-autoplot(PCA1,data=iris,colour='Species')
pca2_plot