# [R] plot

Barry Rowlingson B.Rowlingson at lancaster.ac.uk
Fri Dec 9 13:05:51 CET 2005

```Rhett Eckstein wrote:
> Dear R users:
>
>
>>C1
>
>    time        X1
> 1   0.5  6.296625
> 2   1.0 10.283977
> 3   1.5 12.718610
> 4   2.0 14.112740
> 5   3.0 15.053917
> 6   4.0 14.739725
> 7   6.0 12.912230
> 8   8.0 10.893264
> 9   0.5  6.289166
> 10  1.0 10.251247
> 11  1.5 12.651346
> 12  2.0 14.006958
> 13  3.0 14.870618
> 14  4.0 14.487026
> 15  6.0 12.555566
> 16  8.0 10.474695
>
>>plot(C1,type="l")
>
> In the plot, there is a straight line between time=0.5 and time=8,
> If I do not want the straight line, what should I do?

What do you want? Looking at your data makes me think you want two
separate lines, in which case you probably want to do a plot() followed
by a lines(), or better still with a slight rearrangement of your data
you can use matplot() which is designed for doing several lines (or sets
of points) in one plot.

Something like:

matplot(C1\$time[1:8], cbind(C1\$X1[1:8], C1\$X1[9:16]), type='l')

but you may also want to rearrange your dataframe. Try:

C2 = data.frame(time=C1\$time[1:8], X1=C1\$X1[1:8], X2=C1\$X1[9:16])

so it looks something like this (with random numbers):

C2
time          X1        X2
1  0.5 0.754514622 0.2571699
2  1.0 0.006056693 0.7252758
3  1.5 0.694433716 0.5532185
4  2.0 0.201020796 0.4590972
5  3.0 0.114225055 0.8226671
6  4.0 0.569609820 0.9712040
7  6.0 0.306018526 0.6795705
8  8.0 0.142492724 0.3452476

then matplot becomes:

matplot(C2\$time, cbind(C2\$X1,C2\$X2),type='l')

- sticking an NA in the middle (as suggested just now) seems a bit kludgy!

Baz

```