On Thu, 21 Jul 2005, Marc Schwartz (via MN) wrote: >[Note: the initial posts have been re-arranged to attempt to maintain >the flow from top to bottom] > >> >Dan Bolser writes: >> > > >> > > I would like to annotate my plot with a little box containing the slope, >> > > intercept and R^2 of a lm on the data. >> > > >> > > I would like it to look like... >> > > >> > > +----------------------------+ >> > > | Slope : 3.45 +- 0.34 | >> > > | Intercept : -10.43 +- 1.42 | >> > > | R^2 : 0.78 | >> > > +----------------------------+ >> > > >> > > However I can't make anything this neat, and I can't find out how to >> > > combine this with symbols for R^2 / +- (plus minus). >> > > >> > > Below is my best attempt (which is franky quite pour). Can anyone >> > > improve on the below? >> > > >> > > Specifically, >> > > >> > > aligned text and numbers, >> > > aligned decimal places, >> > > symbol for R^2 in the text (expression(R^2) seems to fail with >> > > 'paste') and +- >> > > >> > > >> > > >> > > Cheers, >> > > Dan. >> > > >> > > >> > > dat.lm <- lm(dat$AVG_CH_PAIRS ~ dat$CHAINS) >> > > >> > > abline(coef(dat.lm),lty=2,lwd=1.5) >> > > >> > > >> > > dat.lm.sum <- summary(dat.lm) >> > > dat.lm.sum >> > > >> > > attributes(dat.lm.sum) >> > > >> > > my.text.1 <- >> > > paste("Slope : ", round(dat.lm.sum$coefficients[2],2), >> > > "+/-", round(dat.lm.sum$coefficients[4],2)) >> > > >> > > my.text.2 <- >> > > paste("Intercept : ", round(dat.lm.sum$coefficients[1],2), >> > > "+/-", round(dat.lm.sum$coefficients[3],2)) >> > > >> > > my.text.3 <- >> > > paste("R^2 : ", round(dat.lm.sum$r.squared,2)) >> > > >> > > my.text.1 >> > > my.text.2 >> > > my.text.3 >> > > >> > > >> > > ## Add legend >> > > text(x=3, >> > > y=300, >> > > paste(my.text.1, >> > > my.text.2, >> > > my.text.3, >> > > sep="\n"), >> > > adj=c(0,0), >> > > cex=1 > > >> On Thu, 21 Jul 2005, Christoph Buser wrote: >> >> >Dear Dan >> > >> >I can only help you with your third problem, expression and >> >paste. You can use: >> > >> >plot(1:5,1:5, type = "n") >> >text(2,4,expression(paste("Slope : ", 3.45%+-%0.34, sep = "")), pos = 4) >> >text(2,3.8,expression(paste("Intercept : ", -10.43%+-%1.42)), pos = 4) >> >text(2,3.6,expression(paste(R^2,": ", "0.78", sep = "")), pos = 4) > >> >I do not have an elegant solution for the alignment. > > >On Thu, 2005-07-21 at 19:55 +0100, Dan Bolser wrote: >> Cheers for this. >> >> I was trying to get it to work, but the problem is that I need to replace >> the values above with variables, from the following code... >> >> >> dat.lm <- lm(dat$AVG_CH_PAIRS ~ dat$CHAINS) >> dat.lm.sum <- summary(dat.lm) >> >> my.slope.1 <- round(dat.lm.sum$coefficients[2],2) >> my.slope.2 <- round(dat.lm.sum$coefficients[4],2) >> >> my.inter.1 <- round(dat.lm.sum$coefficients[1],2) >> my.inter.2 <- round(dat.lm.sum$coefficients[3],2) >> >> my.Rsqua.1 <- round(dat.lm.sum$r.squared,2) >> >> >> Anything I try results in either the words 'paste("Slope:", my.slope.1, >> %+-%my.slope.2,sep="")' being written to the plot, or just >> 'my.slope.1+-my.slope2' (where the +- is correctly written). >> >> I want to script it up and write all three lines to the plot with >> 'sep="\n"', rather than deciding three different heights. > > >> Thanks very much for what you gave, its a good start for me to figure out >> how I am supposed to be telling R what to do! >> >> Any way to just get fixed width fonts with text? (for the alignment >> problem) > > >Dan, > >Here is one approach. It may not be the best, but it gets the job done. >You can certainly take this and encapsulate it in a function to automate >the text/box placement and to pass values as arguments. > >A couple of quick concepts: > >1. As far as I know, plotmath cannot do multiple lines, so each line in >your box needs to be done separately. > >2. The horizontal alignment is a bit problematic when using expression() >or bquote() since I don't believe that multiple spaces are honored as >such after parsing. Thus I break up each component (label, ":" and >values) into separate text() calls. The labels are left justified. > >3. The alignment for the numeric values are done with right >justification. So, as long as you use a consistent number of decimals in >the value outputs (2 here), you should be OK. This means you might need >to use formatC() or sprintf() to control the numeric output values on >either side of the +/- sign. > >4. In the variable replacement, note the use of substitute() and the >list of x and y arguments as replacement values in the expressions. > > > ># Set your values >my.slope.1 <- 3.45 >my.slope.2 <- 0.34 > >my.inter.1 <- -10.43 >my.inter.2 <- 1.42 > >my.Rsqua <- 0.78 > > ># Create the initial plot as per Christoph's post >plot(1:5, 1:5, type = "n") > > >#------------------------------------- ># Do the Slope >#------------------------------------- > >text(1, 4.5, "Slope", pos = 4) >text(2, 4.5, ":") >text(3, 4.5, substitute(x %+-% y, > list(x = my.slope.1, > y = my.slope.2)), > pos = 2) > > >#------------------------------------- ># Do the Intercept >#------------------------------------- > >text(1, 4.25, "Intercept", pos = 4) >text(2, 4.25, ":") >text(3, 4.25, substitute(x %+-% y, > list(x = my.inter.1, > y = my.inter.2)), > pos = 2) > > >#------------------------------------- ># Do R^2 >#------------------------------------- > >text(1, 4.0, expression(R^2), pos = 4) >text(2, 4.0, ":") >text(3, 4.0, substitute(x, list(x = my.Rsqua)), > pos = 2) > > >#------------------------------------- ># Do the Box >#------------------------------------- > >rect(1, 3.75, 3, 4.75) > > >You can adjust the x,y coordinates for the various text elements as you >may require and can also calculate them based upon the xlim, ylim of >your actual plot. You can also modify the 'cex' argument to text() for >adjusting the sizes of the fonts in use.
I have been trying many different combinations of the suggestions so far... bquote, substitute, expression, paste, etc. Also I was trying to use the 'expression' part of the 'legend' function to make thing easier (make new lines, make columns, make rectangles)... So far all in vain. I am sure a fairly neat solution is possible using 'legend' and 'expression', but I cant get a legend which contains a variable substituted value *and* a special symbol. Can anyone show me an example of this simple step, and then I can try to build on that. Thanks all for suggestions, its one of those 'it seems so easy' problems (for me). P.S. Whats with the documentation for bquote? >BTW, to use a monospaced font, you can set par(family = "mono"). >See ?par for more information. > >HTH, > >Marc Schwartz > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html