Marking in barplot ()

Question

I am trying to add names to the columns of my line chart ... In each group there are 2 bars that will have the same name.

I am using code like this:

l<-c(.6286, .2212, .9961, .5831, .8703, .6990, .9952, .9948) r<-c(.2721, .5663, .0, .3961, .0696, .1180, .0, .0) tab<-rbind(l,r) plot<-barplot(tab, beside=TRUE, axisnames=FALSE, main = 'Time Spent Left vs. Right', sub = 'Female 2c', xlab= 'Days After Entry', ylab = 'Proportion of Time Spent', col=c('blue', 'red'), ylim = c(0,1)) legend('topleft', .8, c('Left' , 'Right'), pch=c(.8), col=c('blue', 'red')) names.arg = jd2c$d.in.p names.arg=c(3,4,5,6,6,7,10,11) #listed for informational purposes, same as jd2c$d.in.p 

jd2c $ d.in.p is also listed above .. For some reason, the names.arg function does not seem to do what I expect. Even if I put it in the parenthesis of the bar plot () function.

What am I doing wrong?

Thanks!

Answer 1

Using your data and settings names.arg respectively and axisnames=TRUE , I get a reasonable result. I changed a couple of other things (set las=1 to rotate the axes horizontally, use fill , not col in the legend, got rid of pch=0.8 ).

 par(las=1) bnames <- c(3,4,5,6,6,7,10,11) #listed for informational purposes, same as jd2c$ plot<-barplot(tab, beside=TRUE, axisnames=TRUE, main = 'Time Spent Left vs. Right', sub = 'Female 2c', xlab= 'Days After Entry', ylab = 'Proportion of Time Spent', col=c('blue', 'red'), ylim = c(0,1), names.arg=bnames) legend('topleft', cex=1, c('Left' , 'Right'), fill=c('blue', 'red')) 

Answer 2

You define names.arg not as an argument to the barplot function, but as a completely separate variable - it is outside the parentheses. It:

 plot<-barplot(tab, beside=TRUE, axisnames=FALSE, main = 'Time Spent Left vs. Right', sub = 'Female 2c', xlab= 'Days After Entry', ylab = 'Proportion of Time Spent', col=c('blue', 'red'), ylim = c(0,1)) legend('topleft', .8, c('Left' , 'Right'), pch=c(.8), col=c('blue', 'red')) names.arg = jd2c$d.in.p 

it should be:

 plot<-barplot(tab, beside=TRUE, axisnames=FALSE, main = 'Time Spent Left vs. Right', sub = 'Female 2c', xlab= 'Days After Entry', ylab = 'Proportion of Time Spent', col=c('blue', 'red'), ylim = c(0,1), names.arg = jd2c$d.in.p) legend('topleft', .8, c('Left' , 'Right'), pch=c(.8), col=c('blue', 'red')) 

You must also set axisnames=TRUE for the names to appear.