Consider the following snippet of code:

 for _, tt := range a {
 for _, word := range strings.Fields(tt.FullText) {
 wordID, ok := p.single(word)
 if ok {
 tt.ids = append(tt.ids, wordID)
 }
if word == "rt" {
 tt.isRT = true
 }
 }
 p.tfidf.Add(tt)
 }

What it says is after we've preprocessed every single word, we simply add that word to the TFIDF.