R: Combine documents in corpus by a grouping variable

corpus_group {quanteda} | R Documentation

## Combine documents in corpus by a grouping variable

### Description

Combine documents in a corpus object by a grouping variable, by concatenating their texts in the order of the documents within each grouping variable.

### Usage

    corpus_group(x, groups = docid(x), fill = FALSE, concatenator = " ")

### Arguments

`x` | corpus object
`groups` | grouping variable for sampling, equal in length to the number of documents. This will be evaluated in the docvars data.frame, so that docvars may be referred to by name without quoting. This also changes previous behaviours for `groups`. See `news(Version >= "3.0", package = "quanteda")` for details.
`fill` | logical; if `TRUE` and `groups` is a factor, then use all levels of the factor when forming the new documents of the grouped object. This will result in a new "document" with empty content for levels not observed, but for which an empty document may be needed. If `groups` is a factor of dates, for instance, then `fill = TRUE` ensures that the new object will consist of one new "document" by date, regardless of whether any documents previously existed with that date. Has no effect if the `groups` variable(s) are not factors.
`concatenator` | the concatenation character that will connect the grouped documents.

### Value

a corpus object whose documents are equal to the unique group combinations, and whose texts are the concatenations of the texts by group. Document-level variables that have no variation within groups are saved in docvars. Document-level variables that are lists are dropped from grouping, even when these exhibit no variation within groups.

### Examples

    corp <- corpus(c("a a b", "a b c c", "a c d d", "a c c d"),
                   docvars = data.frame(grp = c("grp1", "grp1", "grp2", "grp2")))
    corpus_group(corp, groups = grp)
    corpus_group(corp, groups = c(1, 1, 2, 2))
    corpus_group(corp, groups = factor(c(1, 1, 2, 2), levels = 1:3))

    # with fill
    corpus_group(corp, groups = factor(c(1, 1, 2, 2), levels = 1:3), fill = TRUE)

[Package quanteda version 3.0.0 Index]