I am trying to get through this tutorial on micrarray data analysis by daniel swan. I am however, getting stuck at the annotation part, when I try to annotate the probeset ids with the gene symbols. Here's what I'm getting
> gene.symbols <- getSYMBOL(probeset.list, "hgu133plus2")
Error in unlist(lookUp(x, data, "SYMBOL")) :
error in evaluating the argument 'x' in selecting a method for function 'unlist': Error in .checkKeysAreWellFormed(keys) :
keys must be supplied in a character vector with no NAs
Also, the following command gives me a NULL result.
So the problem is that there is no 'ID' column right ? How do I get around this ?