[R] trajectory plot (growth curve)

[Gabor Grothendieck]

On Mon, Aug 23, 2010 at 4:16 PM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> On Mon, Aug 23, 2010 at 3:58 PM, Lei Liu <liulei at virginia.edu> wrote:
>> Hi there,
>>
>> I want to make trajectory plots for data as follows:
>>
>> ID      time    y
>> 1       1       1.4
>> 1       2       2.0
>> 1       3       2.5
>> 2       1.5     2.3
>> 2       4       4.5
>> 2       5.5     1.6
>> 2       6       2.0
>>
>> ...
>>
>> That is, I will plot a growth curve for each subject ID, with y in the y
>> axis, and time in the x axis. I would like to have all growth curves in the
>> same plot. Is there a simple way in R to do it? Thanks a lot!
>>
>
> Try this.
>
> Lines <- "ID      time    y
> 1       1       1.4
> 1       2       2.0
> 1       3       2.5
> 2       1.5     2.3
> 2       4       4.5
> 2       5.5     1.6
> 2       6       2.0"
>
> library(zoo)
>
> # z <- read.zoo("myfile.dat", header = TRUE, split = 1, index = 2)
> z <- read.zoo(textConnection(Lines), header = TRUE, split = 1, index = 2)
>
> plot(z) # each in separate panel
> plot(z, col = 1:2) # all on same plot in different colors
>

or better:

plot(na.approx(z))
plot(na.approx(z), col = 1:2)