[R] format numbers without leading or trailing 0s

[William Dunlap]

You may also want to deal with a possible
leading negative sign:

  > lambda <- c(0, 0.005, 0.01, 0.02, 0.04, 0.08,
               -0.005, -0.01, -0.02, -0.04, -0.08, 1000)
  > gsub("^0(\\..*[^0])0*$","\\1", lambda)
   [1] "0"      ".005"   ".01"    ".02"    ".04"    ".08"   
   [7] "-0.005" "-0.01"  "-0.02"  "-0.04"  "-0.08"  "1000"  
  > gsub("^(-)?0(\\..*[^0])0*$","\\1\\2", lambda) # -0. -> .
   [1] "0"     ".005"  ".01"   ".02"   ".04"   ".08"   "-.005"
   [8] "-.01"  "-.02"  "-.04"  "-.08"  "1000"

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 Bert Gunter
> Sent: Tuesday, November 29, 2011 9:57 AM
> To: Sarah Goslee
> Cc: R-help; Michael Friendly
> Subject: Re: [R] format numbers without leading or trailing 0s
> 
> .. and if you want to simultaneously handle possible multiple trailing
> zeros (not sure whether this could even happen)
> 
> (somewhat but not completely tested)
> 
> > lambda <- c(0, 0.005, 0.01, 0.02, 0.04, 0.08)
> > gsub("^0(\\..*[^0])0*$","\\1",lambda)
> [1] "0"    ".005" ".01"  ".02"  ".04"  ".08"
> 
> Note that the as.character() coercion is done automatically (and is
> documented to be).
> 
> If you do much of this, it's worth going through one of the many web
> tutorials on regular expressions. And if you're a minimalist like me,
> you may even find R's man page, ?regexp), suffices.
> 
> Cheers,
> Bert
> 
> 
> 
> On Tue, Nov 29, 2011 at 9:09 AM, Sarah Goslee <sarah.goslee at gmail.com> wrote:
> > Here's one way to get rid of leading zeros before the
> > decimal point:
> >
> >> gsub("^0\\.", "\\.", as.character(lambda))
> > [1] "0"    ".005" ".01"  ".02"  ".04"  ".08"
> >
> > Sarah
> >
> > On Tue, Nov 29, 2011 at 12:04 PM, Michael Friendly <friendly at yorku.ca> wrote:
> >> A simple question, but I can't find something to do what I want:
> >>
> >> Given: a vector of numbers, like
> >>
> >> lambda <- c(0, 0.005, 0.01, 0.02, 0.04, 0.08)
> >>
> >> Desired: format them in minimal space for use as plot labels, ie, without
> >> leading or tailing 0s. For this example:
> >>
> >> lambdaf <- c("0", .005", ".01", ".02", ".04", ".08")
> >>
> >> --
> >
> >
> > --
> > Sarah Goslee
> > http://www.functionaldiversity.org
> >
> > ______________________________________________
> > R-help at 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.
> >
> 
> 
> 
> --
> 
> Bert Gunter
> Genentech Nonclinical Biostatistics
> 
> Internal Contact Info:
> Phone: 467-7374
> Website:
> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
> 
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.