Hi,

I am running fitZig for differential abundance testing. When I place:

treatment=pData(obj)$Treatment

Before=pData(obj)$Time

normFactor=normFactors(obj)

normFactor=log2(normFactor/median(normFactor)+1)

mod = model.matrix (Treatment + Before + normFactor), the answer is:

Error: $ operator is invalid for atomic vectors

Based on internet there is  an error when applying $ to a vector. But how can I fix the problem in the script? 

Thanks!!

PJ

Missing '~' in the formula specification?

mod = model.matrix(~Treatment+Before+normFactor)