On Sun, Aug 15, 2010 at 2:04 PM, James Toll <ja...@jtoll.com> wrote: > 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
xblocks is part of zoo, not xts. Try this: z <- as.zoo(xtsPR)[, 1] plot(z) xblocks(z > 0.05, col = "red") You have passed a logical vector to xblocks whereas you should have passed a time series. See help(xblocks) > > 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.
