tfidf function

tf-idf

term frequency, inverse document frequency

tfidf(x,normalize=TRUE)

Arguments

• x: A dgCMatrix or matrix of counts.
• normalize: Whether to normalize term frequency by document totals.

Returns

A matrix of the same type as x, with values replaced by the tf-idf

where $f_{ij}$ is $x_{ij}/m_i$ or $x_{ij}$, depending on normalize, and $d_j$ is the number of documents containing token $j$.

Author(s)

Matt Taddy taddy@chicagobooth.edu

Examples

data(we8there)
## 20 high-variance tf-idf terms
colnames(we8thereCounts)[
        order(-sdev(tfidf(we8thereCounts)))[1:20]]

See Also

pls, we8there