# Re: [R] Question about 'text' (add lm summary to a plot)

From: Dan Bolser <dmb_at_mrc-dunn.cam.ac.uk>
Date: Fri 22 Jul 2005 - 04:55:16 EST

>Dear Dan
>
>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)
>

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)

Cheers,
Dan.

>
>Regards,
>
>Christoph Buser
>
>--------------------------------------------------------------
>Christoph Buser <buser@stat.math.ethz.ch>
>Seminar fuer Statistik, LEO C13
>ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND
>phone: x-41-44-632-4673 fax: 632-1228
>http://stat.ethz.ch/~buser/
>--------------------------------------------------------------
>
>
>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
> >
> >
> > text(x=3,
> > y=300,
> > paste(my.text.1,
> > my.text.2,
> > my.text.3,
> > sep="\n"),
> > cex=1)
> >
> > ______________________________________________
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> > https://stat.ethz.ch/mailman/listinfo/r-help