R: Locate a pattern in a tokens object

index {quanteda} | R Documentation

## Locate a pattern in a tokens object

### Description

Locates a pattern within a tokens object, returning the index positions of the beginning and ending tokens in the pattern.

### Usage

    index(
      x,
      pattern,
      valuetype = c("glob", "regex", "fixed"),
      case_insensitive = TRUE
    )

    is.index(x)

### Arguments

`x` | an input tokens object
`pattern` | a character vector, list of character vectors, dictionary, or collocations object. See pattern for details.
`valuetype` | the type of pattern matching: `"glob"` for "glob"-style wildcard expressions; `"regex"` for regular expressions; or `"fixed"` for exact matching. See valuetype for details.
`case_insensitive` | logical; if `TRUE`, ignore case when matching a `pattern` or dictionary values

### Value

a data.frame consisting of one row per pattern match, with columns for the document name, index positions `from` and `to`, and the pattern matched.

`is.index` returns `TRUE` if the object was created by `index()`; `FALSE` otherwise.

### Examples

    toks <- tokens(data_corpus_inaugural[1:8])
    index(toks, pattern = "secure*")
    index(toks, pattern = c("secure*", phrase("united states"))) %>% head()

[Package quanteda version 3.0.0 Index]