mypca

mypca.R

mypca<-function(x, mytitle="", ...)
{
  par(mfrow=c(1,1))
  this_pc <- prcomp(x, scale=FALSE)
  this_pc_coord <- this_pc$x
  pc1pct=round(summary(this_pc)$importance[2,1]*100,2)
  pc2pct=round(summary(this_pc)$importance[2,2]*100,2)
  par(mar = c(8, 5, 3, 8), xpd=T)
  plot(this_pc_coord[,1], this_pc_coord[,2], pch = 19, cex=2, 
       xlab=paste0("PC1(",pc1pct,"%)"),ylab=paste0("PC2(",pc2pct,"%)"), bty="l", xpd=T,
       main=mytitle)
  abline(h=0, v=0, lty = 2, xpd=F, lwd=.1, col="gray70")
  text(this_pc_coord[,1], this_pc_coord[,2], labels=rownames(this_pc_coord),
       cex=1, pos = 4)
}