So I have two sets of data (of different length) that I am trying to group up and display the density plots for:

```
dat <- data.frame(dens = c(nEXP,nCNT),lines = rep(c("Exp","Cont")))
ggplot(dat, aes(x = dens, group=lines, fill = lines)) + geom_density(alpha = .5)

```

when I run the code it spits an error about the different lengths, i.e. 
"arguments imply different num of rows: x, y"

I then augment the code to:

```
dat <- data.frame(dens = c(nEXP,nCNT),lines = rep(c("Exp","Cont"),X))

```

Where X is the length of the longer argument so the lengths of "lines" will match that of dens.

Now the issue is that when when I go to plot the data I am only getting ONE density plot.... I know there should be two, since plotting the densities with plot/lines, is clearly two non-equal overlapping distributions, so I am assuming the error is with the grouping...

hope that makes sense.