`clojure.string/trim`¶

Type: function Added: Clojure 1.2 Examples: 3 Runnable: 0

([s])

Removes whitespace from both ends of string.

Examples¶

by gstamp on 2010-10-01 . May have evaluation errors.

by cljlc on 2018-02-21 . May have evaluation errors.

;; trim might not do what you expect
;; if your string starts/ends with 'separator' ascii control codes.

;; This is because these characters are treated as
;; whitespace in trim (and trimr and triml), but
;; non-whitespace in the regex #"\s" (and \S).

;; In other words either you believe they are whitespaces or not whitespaces,
;; you can be surprised when using trim/trimr/triml or when using #"\s" or #"\S":
;; "whitespace" for trim is NOT the same as
;; "whitespace" for \s.

(use 'clojure.string)

(trim "a \u001F")
=> "a"

but

(split "a \u001F" #"\s+")
=> ["a" "\u001F"]
;; instead of ["a"], that could be expected based on trim's behaviour

;; The exact list of these special "characters":
;; Dec Hex (UTF-8)  Unicode (UTF-16BE)  Clojure   Name             Abbreviation
;; 28  1C           U+001C              '\u001C'  File separator   FS
;; 29  1D           U+001D              '\u001D'  Group separator  GS
;; 30  1E           U+001E              '\u001E'  Record separator RS
;; 31  1F           U+001F              '\u001F'  Unit separator   US

;; Background: Clojure's trim uses Java Character's isWhitespace,
;; that has its own definition of whitespace,
;; that differs from the definition of whitespace in the \s
;; "whitespace character class" of Java regex.

;; References:
;; Clojure trim's source: 
;; https://clojure.github.io/clojure/clojure.string-api.html#clojure.string/trim
;; Java Character's isWhitespace: 
;; https://docs.oracle.com/javase/8/docs/api/java/lang/Character.html#isWhitespace-char-
;; Java's \s whitespace character class: 
;; https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html

by saitouena on 2019-11-13 . May have evaluation errors.

clojure.string/trim¶

Examples¶

See also¶

`clojure.string/trim`¶