plot stacked bar plot in R

Question

I would like to create histogram [stacked bar plot] in R with data like this:

Period = c(1,1,2,2,3,3,4,4)                              
Sample = c(\"A\",\"B\         


        

Answer 1

It's not as pretty as the ggplot solution but

v <- rbind(Value1,Value2)
barplot(v,beside=FALSE,names=levels(interaction(Period,Sample)),legend=TRUE)

seems to work.