Conflating categories
On 12/14/2007 7:39 AM, Peter Paul wrote:
Hi, I think this is a pretty basic question. I still couldn#t find the answer to it, though. I have some data loaded into R, which looks like this:
data()
... 38358 Advice Article 38359 Advice Article 38360 GeneralInfo List 38361 GeneralInfo Article 38362 Purchase Paragraphs 38363 Purchase List 38364 Purchase Paragraphs ... I now would like to edit the data in such a way that every "Advice" is changed into "GeneralInfo". Is there some easy way how I can do this?
This is a little tricky, because R has probably converted those columns into factors. Let's assume that column 2 is named Type and the dataset is named dat. Then you replace it as dat$Type[dat$Type == "Advice"] <- "GeneralInfo" You'd think the following would work: dat$Type <- ifelse(dat$Type == "Advice", "GeneralInfo", dat$Type) but it doesn't, because ifelse() loses the factor levels. Factors are one of the most error-prone features of the S language. Duncan Murdoch