str_match {stringr}

Extract components (capturing groups) from a match

Description

Extract any number of matches defined by unnamed, (pattern), and named, ⁠(?<name>pattern)⁠ capture groups.

Use a non-capturing group, ⁠(?:pattern)⁠, if you need to override default operate precedence but don't want to capture the result.

Usage

str_match(string, pattern)

str_match_all(string, pattern)

Arguments

string

Input vector. Either a character vector, or something coercible to one.

pattern

Unlike other stringr functions, str_match() only supports regular expressions, as described vignette("regular-expressions"). The pattern should contain at least one capturing group.

Value

• str_match(): a character matrix with the same number of rows as the length of string/pattern. The first column is the complete match, followed by one column for each capture group. The columns will be named if you used "named captured groups", i.e. ⁠(?<name>pattern')⁠.

• str_match_all(): a list of the same length as string/pattern containing character matrices. Each matrix has columns as descrbed above and one row for each match.

See Also

str_extract() to extract the complete match, stringi::stri_match() for the underlying implementation.

Examples

strings <- c(" 219 733 8965", "329-293-8753 ", "banana", "595 794 7569",
  "387 287 6718", "apple", "233.398.9187  ", "482 952 3315",
  "239 923 8115 and 842 566 4692", "Work: 579-499-7527", "$1000",
  "Home: 543.355.3679")
phone <- "([2-9][0-9]{2})[- .]([0-9]{3})[- .]([0-9]{4})"

str_extract(strings, phone)
str_match(strings, phone)

# Extract/match all
str_extract_all(strings, phone)
str_match_all(strings, phone)

# You can also name the groups to make further manipulation easier
phone <- "(?<area>[2-9][0-9]{2})[- .](?<phone>[0-9]{3}[- .][0-9]{4})"
str_match(strings, phone)

x <- c("<a> <b>", "<a> <>", "<a>", "", NA)
str_match(x, "<(.*?)> <(.*?)>")
str_match_all(x, "<(.*?)>")

str_extract(x, "<.*?>")
str_extract_all(x, "<.*?>")