[BioC] passing arguments to makeContrast

[rcaloger]

Hi,
I am trying to build a function in which I will pass the contrasts of a 
linear model as a parameter of the function.
The question is how can I pass the contrasts if they are inserted in a 
object:
if I do:
tmp=makeContrasts("ctrl-trt", levels=c("ctrl", "trt"))
works!

if instead I do
mycontrast="ctrl-trt"
tmp=makeContrasts(mycontrast, levels=c("ctrl", "trt"))
 it does not and I get the error:
Error in eval(expr, envir, enclos) : object "mycontrast" not found

There is any trick to pass my contrasts if they are inserted in an object?

Thanks
Raffaele

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Prof. Raffaele A. Calogero
Bioinformatics and Genomics Unit
Dipartimento di Scienze Cliniche e Biologiche
c/o Az. Ospedaliera S. Luigi
Regione Gonzole 10, Orbassano
10043 Torino
tel.   ++39 0116705420
Lab.   ++39 0116705408
Fax    ++39 0119038639
Mobile ++39 3333827080
email: raffaele.calogero at unito.it
www:   www.bioinformatica.unito.it