R: Read Document-Term Matrices

foreign {tm} | R Documentation

## Read Document-Term Matrices

### Description

Read document-term matrices stored in special file formats.

### Usage

    read_dtm_Blei_et_al(file, vocab = NULL)
    read_dtm_MC(file, scalingtype = NULL)

### Arguments

`file` | a character string with the name of the file to read.
`vocab` | a character string with the name of a vocabulary file (giving the terms, one per line), or `NULL`.
`scalingtype` | a character string specifying the type of scaling to be used, or `NULL` (default), in which case the scaling will be inferred from the names of the files with non-zero entries found (see Details).

### Details

`read_dtm_Blei_et_al` reads the (List of Lists type sparse matrix) format employed by the Latent Dirichlet Allocation and Correlated Topic Model C codes by Blei et al (http://www.cs.columbia.edu/~blei).

MC is a toolkit for creating vector models from text documents (see http://www.cs.utexas.edu/users/dml/software/mc/). It employs a variant of Compressed Column Storage (CCS) sparse matrix format, writing data into several files with suitable names: e.g., a file with ‘_dim’ appended to the base file name stores the matrix dimensions. The non-zero entries are stored in a file the name of which indicates the scaling type used: e.g., ‘_tfx_nz’ indicates scaling by term frequency (t), inverse document frequency (f) and no normalization (x). See ‘README’ in the MC sources for more information.

`read_dtm_MC` reads such sparse matrix information with argument `file` giving the path with the base file name.

### Value

A document-term matrix.

### See Also

`read_stm_MC` in package slam.

[Package tm version 0.7-5 Index]