[R] multiple line plots

[sosman]

Marc Schwartz wrote:
 > On Wed, 2005-10-05 at 22:19 +1000, sosman wrote:
 >
 >>I have some data in a CSV file:
 >>
 >>time,pos,t,tl
 >>15:23:44:350,M1_01,4511,1127
 >>15:23:44:350,M1_02,4514,1128
 >>15:23:44:350,M1_03,4503,1125
 >>...
 >>15:23:44:491,M2_01,4500,1125
 >>15:23:44:491,M2_02,4496,1124
 >>15:23:44:491,M2_03,4516,1129
 >>...
 >>15:23:44:710,M3_01,4504,1126
 >>15:23:44:710,M3_02,4516,1129
 >>15:23:44:710,M3_03,4498,1124
 >>...
 >>
 >>Each pos (eg M1_01) is an independent time series.  I would like to plot
 >>each time series as lines on a single plot and I wondered if there was
 >>something more straight forward than I was attempting.
 >>
 >>I got as far as:
 >>
 >>fname = 't100.csv'
 >>t = read.csv(fname)
 >>tpos = split(t, t$pos)
 >>plot(tpos[["M1_01"]]$t, type='l')
 >>for (p in names(tpos)) {
 >>     lines(tpos[[p]]$t)
 >>}
 >>
 >>which seems to work but then I got stuck on how to make each line a
 >>different colour and figured that there might a be a one liner R command
 >>to do what I want.
 >>
 >>Any tips would be appreciated.
 >
 >
 >
 > See the examples in ?plot.ts for some approaches.
 >
 > You will need to review ?ts to create time series objects from your data
 > to be used in plot.ts().
 >
 > Another approach, which is not specific to time series, is ?matplot.

The matplot example looks like the go.

The example data didn't really show the grouping and even though I
mentioned time series, simply plotting the t values as an ordered
sequence is fine for this application (sorry about the red herring).

The dataset below is what I should have shown:

     pos    t
1 M1_01 4511
2 M1_02 4514
3 M1_03 4503
4 M1_01 4500
5 M1_02 4496
6 M1_03 4516
7 M1_01 4504
8 M1_02 4516
9 M1_03 4498

So what I ended up with was:

# Make a wide data set
tw = unstack(t, t ~ pos)
# Results in a list since not all series the same length
# Find the shortest dataset
len = min(sapply(tw, length))

setlen = function(l, newlen) { length(l) = newlen }
# Not sure why this did not work
#sapply(tw, setlen, len)

for (n in names(tw)) {
     length(tw[[n]]) = len
}
matplot(data.frame(tw), type='l')

Apart from flying a bit blind, I obtained the plot I was after.

thanks