On Aug 15, 2010, at 10:40 AM, Gabor Grothendieck wrote: > On Sun, Aug 15, 2010 at 12:21 PM, James Toll wrote: >> Hi, >> >> I am trying to add a rectangular colored background area to a plot of a time >> series of relative price changes. I believe that what I'm trying to do is >> very similar to the question and example given here: >> >> http://www.mail-archive.com/r-h...@stat.math.ethz.ch/msg73948.html >> http://www.mayin.org/ajayshah/KB/R/html/g5.html >> >> My problem/difference is that my time series looks like so: >> >>> library(quantmod) >>> getSymbols("^GSPC", from="2008-01-01") >>> xtsPR <- diff(log(Ad(GSPC))) >>> head(xtsPR) >> GSPC.Adjusted >> 2008-01-02 NA >> 2008-01-03 0.000000000 >> 2008-01-04 -0.024857950 >> 2008-01-07 0.003218041 >> 2008-01-08 -0.018522677 >> 2008-01-09 0.013532064 >> >> So my dates along the x-axis are in the format "2008-01-02" rather than >> "2008", as in the example. >> >> To keep things simple, I've simply been trying to plot the time series using >> the plot command: >> >> plot(xtsPR) >> >> and then adding either a polygon, or preferably, a rect: >> >> rect(2009-01-02, -0.10, 2009-12-31, 0.10, border = 0, col = "blue") >> >> But nothing is added to the plot when I try to add the rectangle, but I >> don't get an error message either. >> >> My question is how do I specify my x coordinates to draw the polygon or >> rect, given that my scale is of the form "2008-01-02" rather than simply >> "2008"? >> >> Additionally, do I have to use polygon, even if I'm trying to drawing a >> rectangle, as was the case in the examples linked above? >> >> I'd like to be able to use this with chartSeries, rather than plot, but I >> thought it would be easiest to figure it out using plot first. Clearly that >> hasn't helped me. >> > > Try this for several examples: > > library(zoo) > example(xblocks)
Thank you for the suggestion. I couldn't get it to work with my time series, but I did try some of the examples from ?xblocks which is pretty interesting, and I'll probably end up using that elsewhere. Trying to apply xblocks to my time series, I get the error: > xblocks(xtsPR < 0.05, col = rgb[1]) Error in rle(y) : 'x' must be an atomic vector Even if I could get xblocks to work, I don't think it would do exactly what I'm looking for. I get the feeling that I need to find a way to get either rect or polygon to work with my time series. The question is how to define the coordinates of a rect or polygon in terms of time along the x-axis? Thanks James ______________________________________________ R-help@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.
