[R] plotting every ith data point?
Jessi Brown
jessilbrown at gmail.com
Thu Feb 21 02:57:23 CET 2008
Thanks for the ideas so far, Gabor and Phil.
I was hoping to find a solution that didn't depend on building another
data frame, but if that's the easiest way, I can certainly do it
through that route. At least your solutions involve fewer lines of
code than I had devised for extracting the desired rows (am still a
newbie at data manipulation with R!).
cheers, Jessi
On Wed, Feb 20, 2008 at 7:08 PM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> Try this:
>
> ix <- seq(1, nrow(example.df), 5)
> with(example.df[ix,], {
> plot(DSR1 ~ StartDate, type = "b", ylim = c(0.3, 0.9))
> points(DSR2 ~ StartDate, type = "b", pch = 3)
> })
>
>
>
>
> On Wed, Feb 20, 2008 at 6:57 PM, Jessi Brown <jessilbrown at gmail.com> wrote:
> > Hello, fellow R enthusiasts.
> >
> > Ok, I've been racking my brain about this small issue, and between
> > searching the help archives and reading through the plot-related
> > documentation, I can't figure out how to achieve my desired endpoint
> > without some ugly, brute force coding.
> >
> > What I would like to do is make a plot in which only a subset of my
> > data are plotted, but in regular intervals, such as every 5th point
> > along the sequence. Is anyone aware of a built-in function in plot or
> > a related graphing family that can do this, or alternatively, a simple
> > way to extract the desired rows from my original dataframe? I want to
> > do this because I want to plot multiple series of points with their
> > confidence intervals (arrows), and even if I specify type="b," the
> > output ends up looking like just a series of crowded points.
> >
> > For example, if you try making the plot below, you will see how
> > crowded two lines look without error bars:
> >
> > > example.df<-data.frame(StartDate=(94:157), DSR1=seq(0.4, 0.8, length.out=64), DSR2=seq(0.3, 0.9, length.out=64))
> > > plot(example.df$StartDate, example.df$DSR1, type="b", ylim=c(0.3,0.9))
> > > points(example.df$StartDate, example.df$DSR2, type="b", pch=3)
> >
> > Any ideas for an elegant solution to my dilemma?
> >
> > Thanks in advance for any help.
> >
> > cheers, Jessi Brown
> >
> > Ph.D. student
> > Program in Ecology, Evolution, and Conservation Biology
> > University of Nevada, Reno
> >
> > ______________________________________________
> > R-help at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
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