dfm: Create a document-feature matrix

In quanteda: Quantitative Analysis of Textual Data

Create a document-feature matrix

Description

Construct a sparse document-feature matrix from a tokens or dfm object.

Usage

dfm(
  x,
  tolower = TRUE,
  remove_padding = FALSE,
  verbose = quanteda_options("verbose"),
  ...
)

Arguments

x	a tokens or dfm object.
tolower	convert all features to lowercase.
remove_padding	logical; if TRUE, remove the "pads" left as empty tokens after calling tokens() or tokens_remove() with padding = TRUE.
verbose	display messages if TRUE.
...	not used.

Value

a dfm object

Changes in version 3

In quanteda v4, many convenience functions formerly available in dfm() were removed.

See Also

as.dfm(), dfm_select(), dfm

Examples

## for a corpus
toks <- data_corpus_inaugural |>
  corpus_subset(Year > 1980) |>
  tokens()
dfm(toks)

# removal options
toks <- tokens(c("a b c", "A B C D")) |>
    tokens_remove("b", padding = TRUE)
toks
dfm(toks)
dfm(toks) |>
 dfm_remove(pattern = "") # remove "pads"

# preserving case
dfm(toks, tolower = FALSE)

quanteda documentation built on Sept. 11, 2024, 6:08 p.m.