I am using R's quanteda package and the latest versions for both R and the package. I have a corpus of documents which number in the millions.
Let's suppose I have a DFM generated from quanteda with each document having a docvar of the date. There are thousands of documents generated in a given day, but I want to obtain the DFMs applied to the documents by day (so that I have total word counts for each term by day). I know that quanteda is built using data.table, so it should be possible to do this, but I have found little in the "Getting Started with Quanteda" or on StackOverflow that gives a clean way of doing this.
Any suggestions?
You want the 'groups' argument to dfm:
> # Add some random dates to an existing corpus
> docvars(data_corpus_inaugural)$date <- rep(as.Date(runif(19, 1, 18000), origin='1970-01-01'), 3)
> dfm_inaugural <- dfm(data_corpus_inaugural, groups='date')
> head(dfm_inaugural)
Document-feature matrix of: 19 documents, 9,215 features (80.8% sparse).
(showing first 6 documents and first 6 features)
features
docs fellow citizens i appear before you
1970-12-27 4 7 39 2 10 17
1972-04-25 8 13 29 1 8 8
1973-08-22 1 3 48 1 6 1
1973-10-11 2 4 25 0 3 5
1974-01-05 3 9 57 0 7 2
1975-04-12 7 21 63 4 6 16