phrase.matrix: Make matrix of where phrases appear in corpus.
Description
Construct a $n X p$ matrix of appearances for selected phrases out of textreg object.
$n$ is the number of documents, $p$ is the number of phrases selected in the result object `rules.'
Usage
phrase.matrix(rules, n)
Arguments
rules
Either a textreg.result object or the rules list from such an object.
n
(Optional) If giving a rules list, the number of documents in corpus.