R: Create a capture group

capture {rex} | R Documentation

## Create a capture group

### Description

Used to save the matched value within the group for use later in the regular expression or to extract the values captured. Both named and unnamed groups can later be referenced using `capture_group`.

### Usage

    capture(..., name = NULL)

    capture_group(name)

### Arguments

`...` | `shortcuts`, R variables, text, or other rex functions.
`name` | of the group. Unnamed capture groups are numbers starting at 1 in the order they appear in the regular expression. If two groups have the same name, the leftmost group is the used in any reference.

### See Also

`group` for grouping without capturing. Perl 5 Capture Groups http://perldoc.perl.org/perlre.html#Capture-groups

Other rex: `%or%`, `character_class`, `counts`, `group`, `lookarounds`, `not`, `rex`, `shortcuts`, `wildcards`

### Examples

    # Match paired quotation marks
    re <- rex(
      # first quotation mark
      capture(quotes),

      # match all non-matching quotation marks
      zero_or_more(except(capture_group(1))),

      # end quotation mark (matches first)
      capture_group(1)
    )

    #named capture - don't match apples to oranges
    re <- rex(
      capture(name = "fruit", or("apple", "orange")),
      "=",
      capture_group("fruit")
    )

[Package rex version 1.1.1 Index]