[BioC] Affy: Present calls in an eset

[Arne.Muller at aventis.com]

Hello,

I'm quite new to Bioconductor/affy, and I was wondering if there's a simple
way to include the absent/present call for a gene in the outputfile generated
with write.exprs(eset, file='boo') in theaffy package.

the eset was generated with

eset <- expresso(cel, bgcorrect.method = 'rma', normalize.method =   
             'qspline', pmcorrect.method = 'pmonly', 
             summary.method='liwong')

For further analyses I'd like to exclude genes that are absent in all chips.

	thanks a lot for your help,

	Arne