The code is this:
gset <- ReadAffy()
pData(gset)
b1<-log2(exprs(gset))
boxplot(b1, col = 2:4)
str(exprs(gset))
List of 1
$ : symbol gset
At the third line, I get this error"Error in log2(exprs(gset)): non-numeric argument to mathematical function".
I used the same code and the same data a few days ago without any problem but now I don't know what's wrong. I haven't changed anything.