[BioC] variable as argument to makeContrasts (limma)

[Georg Otto]

Hi,

maybe this is a more general R programming question, but I first try it
here, because the problem occured to me with limma:

I use the function makeContrasts

makeContrasts(...,levels=design)

like this

makeContrasts(B-A,C-B,C-A,levels=design)


now instead of giving explicitely "B-A,C-B,C-A" I would like to replace
this by a variable, eg:

a<-c("B-A","C-B","C-A")

makeContrasts(a,levels=design)

unfortunately, this does not work.

So my question is: how can I make this work, and - more generally - how
can I replace the "..." option in a function by a variable?

Thanks,

Georg