R: Simple Corpora

SimpleCorpus {tm} | R Documentation

## Simple Corpora

### Description

Create simple corpora.

### Usage

    SimpleCorpus(x, control = list(language = "en"))

### Arguments

`x` | a `DataframeSource`, `DirSource` or `VectorSource`.
`control` | a named list of control parameters. `language` a character giving the language (preferably as IETF language tags, see language in package NLP). The default language is assumed to be English (`"en"`).

### Details

A simple corpus is fully kept in memory. Compared to a `VCorpus`, it is optimized for the most common usage scenario: importing plain texts from files in a directory or directly from a vector in R, preprocessing and transforming the texts, and finally exporting them to a term-document matrix. It adheres to the `Corpus` API. However, it takes internally various shortcuts to boost performance and minimize memory pressure; consequently it operates only under the following contraints:

- only `DataframeSource`, `DirSource` and `VectorSource` are supported,

- no custom readers, i.e., each document is read in and stored as plain text (as a string, i.e., a character vector of length one),

- transformations applied via `tm_map` must be able to process character vectors and return character vectors (of the same length),

- no lazy transformations in `tm_map`,

- no meta data for individual documents (i.e., no `"local"` in `meta`).

### Value

An object inheriting from `SimpleCorpus` and `Corpus`.

### See Also

`Corpus` for basic information on the corpus infrastructure employed by package tm.

`VCorpus` provides an implementation with volatile storage semantics, and `PCorpus` provides an implementation with permanent storage semantics.

### Examples

    txt <- system.file("texts", "txt", package = "tm")
    (ovid <- SimpleCorpus(DirSource(txt, encoding = "UTF-8"),
                          control = list(language = "lat")))

[Package tm version 0.7-8 Index]