context-class: Context class.
In polmineR: Verbs and Nouns for Corpus Analysis

context-class

R Documentation

Context class.

Description

Class to organize information of context analysis.

Usage

## S4 method for signature 'context'
length(x)

## S4 method for signature 'context'
p_attributes(.Object)

## S4 method for signature 'context'
count(.Object)

## S4 method for signature 'context'
sample(x, size)

## S4 method for signature 'context'
enrich(
  .Object,
  s_attribute = NULL,
  p_attribute = NULL,
  decode = FALSE,
  stat = FALSE,
  verbose = TRUE,
  ...
)

## S4 method for signature 'context'
as.regions(x, node = TRUE)

## S4 method for signature 'context'
trim(
  .Object,
  s_attribute = NULL,
  positivelist = NULL,
  p_attribute = p_attributes(.Object),
  regex = FALSE,
  stoplist = NULL,
  fn = NULL,
  verbose = TRUE,
  progress = TRUE,
  ...
)

Arguments

`x`	A `context` object.
`.Object`	A `context` object.
`size`	An `integer` indicating sample size.
`s_attribute`	The s-attribute(s) to add to `data.table` in slot `cpos`.
`p_attribute`	The p-attribute(s) to add to `data.table` in slot `cpos`.
`decode`	A `logical` value, whether to convert integer ids to expressive strings.
`stat`	A `logical` value, whether to generate / update slot `stat` from the `cpos` table.
`verbose`	A `logical`, whether to be talkative.
`...`	To maintain backwards compatibility if argument `pAttribute` is still used.
`node`	A logical value, whether to include the node (i.e. query matches) in the region matrix generated when creating a `partition` from a `context`-object.
`positivelist`	Tokens that are required to be present to keep a match.
`regex`	A `logical` value, whether arguments `positivlist` / `stoplist` are interpreted as regular expressions.
`stoplist`	Tokens that are used to exclude a match.
`fn`	A function that will be applied on context tables splitted by match_id.
`progress`	A `logical` value, whether to show progress bar

Details

Objects of the class context include a data.table in the slot cpos. The data.table will at least include the columns "match_id", "cpos" and "position".

The length-method will return the number of hits that were achieved.

The enrich()-method can be used to add additional information to the data.table in the cpos-slot of a context-object.

Slots

query: The query examined (character).
count: An integer value, the number of hits for the query.
partition: The partition the context object is based on.
size_partition: The size of the partition, a length-one integer vector.
left: A length-one integer value, the number of tokens to the left of the query match.
right: An integer value, the number of tokens to the right of the query match.
size: A length-one integer value, the number of tokens covered by the context-object, i.e. the number of tokens in the right and left context of the node as well as query matches.
size_match: A length-one integer value, the number of tokens matches by the query. Identical with the value in slot count if the query is not a CQP query.
size_coi: A length-one integer value, the number of tokens in the right and left context of the node (excluding query matches).
size_ref: A length-one integer value, the number of tokens in the partition, without tokens matched and the tokens in the left and right context.
boundary: An s-attribute (character).
p_attribute: The p-attribute of the query (character).
corpus: The CWB corpus used (character).
stat: A data.table, the statistics of the analysis.
encoding: Object of class character, encoding of the corpus.
cpos: A data.table, with the columns match_id, cpos, position, word_id.
method: A character-vector, statistical test used.
call: Object of class character, call that generated the object.

Examples

# Keep matches for 'oil' only if first position to the left is 'crude'
.fn <- function(x) if (x[position == -1L][["word"]] == "crude") x else NULL
crude_oil <- context("REUTERS", "oil") %>%
  enrich(p_attribute = "word", decode = TRUE) %>%
  trim(fn = .fn)

polmineR documentation built on Nov. 2, 2023, 5:52 p.m.