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legend + expression

2 messages · Pedro Mardones, Marc Schwartz

#
Dear all;

A simple? question.

I'm having a problem with a math expression in the legend of a plot
and I haven't found the way to get this to work, so any help will be
appreciate. Basically I want to include in the plot is the R-squared
and its numerical value, so I tried this:

R2c<-0.82879 # R-squared of calibration model
plot(1:10,1:10)
legend("topleft", legend=c(expression(R[c]^2==format(R2c,nsmall=2))))

Thanks for any hint

PM
#
On Fri, 2007-06-08 at 17:27 -0400, Pedro Mardones wrote:
Try this:

  R2c <- 0.82879

  plot(1:10,1:10)

  R2c.2 <- sprintf("%.2f", R2c)

  legend("topleft", legend = bquote(R[c]^2 == .(R2c.2)))


See ?bquote and if you search the list archives, there are more complex
examples of using 'plotmath' in legends.

Note also that 'nsmall' in format() does not fix the number of digits
after the decimal:
[1] "0.82879"

See ?formatC and ?sprintf for better options.

HTH,

Marc Schwartz