[R] characters, mathematical expressions and computed values

[William Dunlap]

I think that bquote, with its .() operator, suffices for [almost?] any single title;
don't bother fiddling with expression(), substitute(), or parse().   (You can make
those work in many situations, but if you stick with just bquote then you can
spend your time on the title itself.)

E.g.,
  hist(new, main=bquote("Heart Attack (" * bar(X)==.(mean(new)) * ")"))
or, if you want to limit the number of digits after the decimal point,
  hist(new, main=bquote("Heart Attack (" * bar(X)==.(round(mean(new),1)) * ")"))

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> Of 1Rnwb
> Sent: Thursday, October 11, 2012 2:32 PM
> To: r-help at r-project.org
> Subject: [R] characters, mathematical expressions and computed values
> 
> Hello,
> 
> I have to add "Age (bar(x)=14.3) as a title on a chart. I am unable to get
> this to working. I have tried bquote, substitute and expression, but they
> are only doing a part of the job.
> 
> new<-
> c(14.3, 18.5, 18.1, 17.7, 18, 15.9, 19.6, 17.3, 17.8, 17.5, 15.4,
> 16.3, 15, 17.1, 17.1, 16.4, 15.2, 16.7, 16.7, 16.9, 14.5, 16.6,
> 15.8, 15.2, 16.2, 15.6, 15, 17.1, 16.7, 15.6, 15, 15.8, 16.8,
> 17, 15.2, 15.8, 15.7, 14.7, 17.3, 14.9, 16.8, 14.6, 19.3, 15.3,
> 14.7, 13.3, 16.5, 16, 14.2, 16.1, 15.2, 13.4, 17.7, 15.5, 14.5,
> 15.7, 13.6, 14.1, 20, 17.2, 16.5, 14.3, 13.7, 14.7, 15.4, 13.6,
> 17, 17.3, 15.4, 15.5, 16.6, 15.8, 15.7, 14.7, 14.2, 14.2, 14,
> 14.2, 19.1, 17.2, 18.3, 13.9, 16, 15.9, 14.9, 14.6, 15.9, 12.2,
> 14.1, 12, 12.8, 17.1, 17, 15, 15.8, 15.9, 16.1, 18, 14.7, 18.9
> )
> hist(new, xlab='30-day Death Rate',xlim=c(7,22),main=expression("Heart
> Attack(" * bar(X) * ")=" *
> mean(new)))
> 
> I would appreciate any pointers on getting this correct.
> Thanks
> 
> 
> 
> --
> View this message in context: http://r.789695.n4.nabble.com/characters-mathematical-
> expressions-and-computed-values-tp4645916.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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