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TextReuseCorpus

Source: R/TextReuseCorpus.R
TextReuseCorpus.Rd

This is the constructor function for a TextReuseCorpus, modeled on the virtual S3 class Corpus from the tm package. The object is a TextReuseCorpus, which is basically a list containing objects of class TextReuseTextDocument. Arguments are passed along to that constructor function. To create the corpus, you can pass either a character vector of paths to text files using the paths = parameter, a directory containing text files (with any extension) using the dir = parameter, or a character vector of documents using the text = parameter, where each element in the characer vector is a document. If the character vector passed to text = has names, then those names will be used as the document IDs. Otherwise, IDs will be assigned to the documents. Only one of the paths, dir, or text parameters should be specified.

Usage

TextReuseCorpus(
  paths,
  dir = NULL,
  text = NULL,
  meta = list(),
  progress = interactive(),
  tokenizer = tokenize_ngrams,
  ...,
  hash_func = hash_string,
  minhash_func = NULL,
  keep_tokens = FALSE,
  keep_text = TRUE,
  skip_short = TRUE
)

is.TextReuseCorpus(x)

skipped(x)

Arguments

paths

A character vector of paths to files to be opened.

dir

The path to a directory of text files.

text

A character vector (possibly named) of documents.

meta

A list with named elements for the metadata associated with this corpus.

progress

Display a progress bar while loading files.

tokenizer

A function to split the text into tokens. See tokenizers. If value is NULL, then tokenizing and hashing will be skipped.

...

Arguments passed on to the tokenizer.

hash_func

A function to hash the tokens. See hash_string.

minhash_func

A function to create minhash signatures of the document. See minhash_generator.

keep_tokens

Should the tokens be saved in the documents that are returned or discarded?

keep_text

Should the text be saved in the documents that are returned or discarded?

skip_short

Should short documents be skipped? (See details.)

x

An R object to check.

Details

If skip_short = TRUE, this function will skip very short or empty documents. A very short document is one where there are two few words to create at least two n-grams. For example, if five-grams are desired, then a document must be at least six words long. If no value of n is provided, then the function assumes a value of n = 3. A warning will be printed with the document ID of each skipped document. Use skipped() to get the IDs of skipped documents.

This function will use multiple cores on non-Windows machines if the "mc.cores" option is set. For example, to use four cores: options("mc.cores" = 4L).

See also

Accessors for TextReuse objects.

Examples

dir <- system.file("extdata/legal", package = "textreuse")
corpus <- TextReuseCorpus(dir = dir, meta = list("description" = "Field Codes"))
# Subset by position or file name
corpus[[1]]
#> TextReuseTextDocument
#> file : /github/home/R/x86_64-pc-linux-gnu-library/4.5/textreuse/extdata/legal/ca1851-match.txt 
#> hash_func : hash_string 
#> id : ca1851-match 
#> minhash_func : 
#> tokenizer : tokenize_ngrams 
#> content : § 4. Every action shall be prosecuted in the name of the real party
#> in interest, except as otherwise provided in this Act.
#> 
#> § 5. In the case of an assignment of a thing in action, the action by
#> the as
names(corpus)
#> [1] "ca1851-match"   "ca1851-nomatch" "ny1850-match"  
corpus[["ca1851-match"]]
#> TextReuseTextDocument
#> file : /github/home/R/x86_64-pc-linux-gnu-library/4.5/textreuse/extdata/legal/ca1851-match.txt 
#> hash_func : hash_string 
#> id : ca1851-match 
#> minhash_func : 
#> tokenizer : tokenize_ngrams 
#> content : § 4. Every action shall be prosecuted in the name of the real party
#> in interest, except as otherwise provided in this Act.
#> 
#> § 5. In the case of an assignment of a thing in action, the action by
#> the as