Try matching on word boundaries as well: > gsub("\\bCl\\b","(Cl+beta)",as.character(form)) [1] "((Cl+beta) - (V * ka)) + (V * Vm * exp(-(Clm/Vm) * t))"
See ?regexp On Thu, May 28, 2009 at 11:41 AM, Caroline Bazzoli <caroline.bazz...@inserm.fr> wrote: > Dear R-experts, > > I need to replace in an expression the character "Cl" by "Cl+beta" > > But in the following case: > > form<-expression((Cl-(V *ka) ) +(V *Vm *exp(-(Clm/Vm) *t))) > > gsub("Cl","(Cl+beta)",as.character(form)) > > We obtain: > > [1] "((Cl+beta) - (V * ka)) + (V * Vm * exp(-((Cl+beta)m/Vm) * t))" > > > the character "Clm" has been also replaced. > > > How could I avoid this unwanted replacement ? > > > Thank you in advance for any help. > > -- > --------------------------------- > Caroline BAZZOLI > > > INSERM U738 - Université PARIS 7 > UFR de Medecine - Site Bichat > 16 rue Henri Huchard > 75018 PARIS, FRANCE > email: caroline.bazz...@inserm.fr > > www.biostat.fr PFIM: www.pfim.biostat.fr > > ______________________________________________ > R-help@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. > ______________________________________________ R-help@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.