Tomado de: http://www.demog.berkeley.edu/faq/faq.html#SECTION00421000000000000000

How can I draw a population pyramid

Below is a chunk of R code that will draw a pretty nice population pyramid, please adapt it and improve it.

########################################################################
## Sat Mar  9 20:21:19 PST 2002
## Carlm's pretty good population pyramid function.
########################################################################


poppyr<-function(age.male,age.female,agecats=c(0,1,4,seq(5,100,5))){
  ##age.male is a vector of ages of males, age.females is a vector of the
  ## mean batting averages of the New York Yankees, agecats is a
  ## vector of break points of ages -- defaults to a pretty standard
  ## one
  ##
  ## Will draw a pretty good but not quite perfect population pyramid
  
  male.ac<-table(cut(age.male,breaks=agecats))
  female.ac<-table(cut(age.female,breaks=agecats))
  

  ## 5/13/04 Megan Heller reports that some alternative 'figs'
  ## values can improve the appearance of the population pyramid
  ## by eliminating the space between the sexes. Here are
  ## Megan's suggested values:
  #  ##this one looks best in terminal
  #  split.screen(figs=rbind(c(0,.58,0,1),c(.43,1,0,1)))
 ## this one looks best in png (png files are the easiest to
  # import into MSWord -- not that you'd ever want to do that.
  # split.screen(figs=rbind(c(0,.58,0,1),c(.38,1,0,1)))

 
  split.screen(figs=rbind(c(0,.57,0,1),c(.45,1,0,1)))
  screen(1)

  
  barplot(female.ac,horiz=T,names=paste(agecats[-length(agecats)]),
          xlim=c(max(female.ac)*1.1,0),col="#FF9900")
  title("Female")

  screen(2)
  barplot(male.ac,horiz=T,axisnames=F,
          xlim=c(0,max(male.ac)*1.1),col="#0000FF")
  title("Male")

  close.screen(all=T)
}



age.male<-rnorm(10000)*50
age.female<-rnorm(10000)*50
poppyr(age.male,age.female)
mtext(side=3,line=3,text="Population Pyramid",cex=1.5)