I am trying to understand what happens inside the IDF part of the TFIDF vectorizer.
The official sci-kit Learn page says that the shape is (4,9) for a corpus of 4 documents having 9 unique features.
I get the Term Frequency (TF) part, it makes sense to me that ( for every unique feature(9), for each document(4) we calculate each term's frequency, so we get a matrix of shape (4,9)
But what doesn't make sense to me is the IDF part the formula for IDF is
So applying this formula, for every feature (9) we calculate the log ( total no.of documents / no.of docs having the term or feature in it) I think This will result in a shape of (1,9) , please correct my understanding here.