`clojure.core/re-matcher`¶

Type: function Added: Clojure 1.0 Examples: 2 Runnable: 0

([re s])

Returns an instance of java.util.regex.Matcher, for use, e.g. in re-find.

Examples¶

by dakrone on 2010-07-31 . May have evaluation errors.

by cloojure on 2021-06-05 . May have evaluation errors.

;
; Java supports named capture groups
;
; Define a phone number pattern with some named groups
(let [patt (re-pattern "(?<area>\\d{3})-(?<prefix>\\d{3})-(?<tail>\\d{4})")]
  ; `re-matches` will find the capturing groups and stick them in a vector
  ; after the full match The capture groups are numbered starting with 1.
  ; The full match is like group zero.
  (is= ["619-239-5464" "619" "239" "5464"] (re-matches patt "619-239-5464"))

; Construct a java.util.regex.Matcher.  Keep in mind that it is a mutable object!
  (let [matcher (re-matcher patt "619-239-5464")]
    ; Execute the Matcher via `re-find`. It returns all 4 groups and caches them
    (is= ["619-239-5464" "619" "239" "5464"] (re-find matcher))

; `re-groups` simply returns the cached result from the Matcher
    (is= ["619-239-5464" "619" "239" "5464"] (re-groups matcher))

; We need the instance function Matcher.group( <name> ) to
    ; extract the named group
    (is= "619" (.group matcher "area"))
    (is= "239" (.group matcher "prefix"))
    (is= "5464" (.group matcher "tail"))))

Note by r4um¶

17:44 < mearnsh> tsdh: re-matcher should be avoided because the Matcher object it returns mutates in a non-thread-safe way

Note by timmc¶

It's fine to use from a controlled context. For instance, if you have a let that creates a Matcher, pulls out groups, and returns the data, you're working in a single-threaded context and the mutable object never even escapes.

clojure.core/re-matcher¶

Examples¶

Note by r4um¶

Note by timmc¶

See also¶

`clojure.core/re-matcher`¶