Richard, Thank you for a clear example, it works. I tried to play with superpose.polygon before to no avail, this clarifies things.
Another question: would you know how to add gridlines to the plot? I'd like to have a few horizontal gridlines on my barchart plot for better readability. Do I have to write a wrapper for panel.barchart? Thanks Alex On Tue, Sep 16, 2008 at 10:49 AM, <[EMAIL PROTECTED]> wrote: > > I have a basis question regarding the use of color in the lattice > package. I > > read the ?barchart help page and searched the R archives but could not > > understand how to do it. > > > > I just need to plot a barchart using specific colors for my groups, e.g. > > green and red instead of the default lattice colors. How do I do that? > > > > If I say: > > barchart(x ~ a_factor, groups=my_groups, data=my_data, > col=c('green', > > 'red'), auto.key=TRUE) > > > > then my barplot has the correct colors, but the legend does not. What is > the > > correct approach to set colors in barchart? > > Two possibilities: > 1. Manually specify the colours of the rectangles in the key by using the > key argument instead of auto.key > > my_cols <- c("green", "red", "blue") > barchart(yield ~ site, > groups=variety, > data = barley, > col=my_cols, > key=list(text=list(levels(barley$variety)), > rectangles=list(col=my_cols))) > > 2. Set superpose.polygon$col in the plot settings instead of using the col > argument, e.g. > > barchart(yield ~ site, > groups=variety, > data = barley, > auto.key=TRUE, > par.settings=list(superpose.polygon=list(col=my_cols))) > > Regards, > Richie. > > Mathematical Sciences Unit > HSL > > > ------------------------------------------------------------------------ > ATTENTION: > > This message contains privileged and confidential information intended > for the addressee(s) only. If this message was sent to you in error, > you must not disseminate, copy or take any action in reliance on it and > we request that you notify the sender immediately by return email. > > Opinions expressed in this message and any attachments are not > necessarily those held by the Health and Safety Laboratory or any person > connected with the organisation, save those by whom the opinions were > expressed. > > Please note that any messages sent or received by the Health and Safety > Laboratory email system may be monitored and stored in an information > retrieval system. > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------ > Scanned by MailMarshal - Marshal's comprehensive email content security > solution. Download a free evaluation of MailMarshal at www.marshal.com > ------------------------------------------------------------------------ > [[alternative HTML version deleted]] ______________________________________________ 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.