[R] String replacement in an expression

[Caroline Bazzoli]

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


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