dfm_subset: Extract a subset of a dfm

In quanteda: Quantitative Analysis of Textual Data

Extract a subset of a dfm

Description

Returns document subsets of a dfm that meet certain conditions, including direct logical operations on docvars (document-level variables). dfm_subset functions identically to subset.data.frame(), using non-standard evaluation to evaluate conditions based on the docvars in the dfm.

Usage

dfm_subset(
  x,
  subset,
  min_ntoken = NULL,
  max_ntoken = NULL,
  drop_docid = TRUE,
  verbose = quanteda_options("verbose"),
  ...
)

Arguments

x	dfm object to be subsetted.
subset	logical expression indicating the documents to keep: missing values are taken as false.
min_ntoken, max_ntoken	minimum and maximum lengths of the documents to extract.
drop_docid	if TRUE, docid for documents are removed as the result of subsetting.
verbose	if TRUE print a summary of the object returned by the function: the number of documents and, depending on the object, the number of characters, tokens and types, or features and occurrences. The number of tokens includes paddings, but the number of features excludes them.
...	not used

Details

To select or subset features, see dfm_select() instead.

Value

dfm object, with a subset of documents (and docvars) selected according to arguments

Examples

corp <- corpus(c(d1 = "a b c d", d2 = "a a b e",
                 d3 = "b b c e", d4 = "e e f a b"),
               docvars = data.frame(grp = c(1, 1, 2, 3)))
dfmat <- dfm(tokens(corp))
# selecting on a docvars condition
dfm_subset(dfmat, grp > 1)
# selecting on a supplied vector
dfm_subset(dfmat, c(TRUE, FALSE, TRUE, FALSE))

quanteda documentation built on Oct. 21, 2026, 5:07 p.m.