Q:

Plotting multiple lines from multiple data frames

I'm a very beginner to R. So I have 2 data files, A.dat and B.dat like:
1   101203
2   3231233  
3   213213
...

So I did 
A <- read.table("A.dat", col.names = c("time","power"))
B <- read.table("B.dat", col.names = c("time","power"))

And I want to do line plot for A and B in the same system (Sorry, i can't upload image yet). Any suggestions on how to go about?

A:

I prefer using ggplot2 (package can be downloaded from CRAN). This first requires a little data processing:
A$group = "A"
B$group = "B"
dat = rbind(A,B)

and then plotting the figure:
ggplot(aes(x = time, y = power, color = group), data = dat) + geom_line()

For base graphics, something like this should work:
plot(power~time, A)
lines(power~time, B)

