clojure.string/replace

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Type: function Added: Clojure 1.2 Examples: 9 Runnable: 8

([s match replacement])

Replaces all instance of match with replacement in s.

match/replacement can be:

string / string char / char pattern / (string or function of match).

See also replace-first.

The replacement is literal (i.e. none of its characters are treated specially) for all cases above except pattern / string.

For pattern / string, $1, $2, etc. in the replacement string are substituted with the string that matched the corresponding parenthesized group in the pattern. If you wish your replacement string r to be used literally, use (re-quote-replacement r) as the replacement argument. See also documentation for java.util.regex.Matcher's appendReplacement method.

Example: (clojure.string/replace "Almost Pig Latin" #"\b(\w)(\w+)\b" "$2$1ay") -> "lmostAay igPay atinLay"

Examples

by rustem.suniev on 2010-09-13 ▶

(clojure.string/replace "The color is red" #"red" "blue") ;=> "The color is blue"

by JD Huntington on 2011-01-15 ▶

(clojure.string/replace "The color is red." #"[aeiou]" #(str %1 %1)) ;=> "Thee cooloor iis reed."

by jafingerhut on 2011-12-21 . May have evaluation errors. ▶

;; Note: When replace-first or replace have a regex pattern as their ;; match argument, dollar sign ($) and backslash (\) characters in ;; the replacement string are treated specially. ;; Example: first substring that the pattern matches is "fodder", with ;; (o+) matching "o" and (\S+) matching "dder". Replacement string ;; says to replace the entire match "fodder" with $2, the string ;; matched by the second parenthesized group, "dder", followed by $1, ;; "o". (str/replace "fabulous fodder foo food" #"f(o+)(\S+)" "$2$1") ;=> "fabulous ddero oo doo" ;; To avoid this special treatment of $ and \, you must escape them with ;; \. Because it is in a Clojure string, to get one \ we must escape ;; *that* with its own \. (str/replace "fabulous fodder foo food" #"f(o+)(\S+)" "\\$2\\$1") ;=> "fabulous $2$1 $2$1 $2$1" ;; To ensure the replacement is treated literally, call ;; java.util.regex.Matcher/quoteReplacement on it. A shorter name ;; like re-qr can be handy. (import '(java.util.regex Matcher)) ;=> java.util.regex.Matcher (defn re-qr [replacement] (Matcher/quoteReplacement replacement)) ;=> #'user/re-qr (str/replace "fabulous fodder foo food" #"f(o+)(\S+)" (re-qr "$2$1")) ;=> "fabulous $2$1 $2$1 $2$1" ;; Since 1.5, re-qr can be replaced by clojure.string/re-quote-replacement (str/replace "fabulous fodder foo food" #"f(o+)(\S+)" (str/re-quote-replacement "$2$1")) ;=> "fabulous $2$1 $2$1 $2$1"

by dansalmo on 2012-08-12 ▶

;; replaces all a's with 1 and all b's with 2 (clojure.string/replace "a b a" #"a|b" {"a" "1" "b" "2"}) ;=> "1 2 1"

by jafingerhut on 2013-09-13 ▶

;; Note: See clojure.core/subs for discussion of behavior of substrings ;; holding onto references of the original strings, which can ;; significantly affect your memory usage in some cases.

by Corin on 2014-04-11 ▶

;; To title case (clojure.string/replace "hello world" #"\b." #(.toUpperCase %1)) "Hello World" ;; Note that a vector is passed to your replacement function ;; when pattern contains capturing groups (see re-groups) (clojure.string/replace "hello world" #"\b(.)" #(.toUpperCase (%1 1))) "Hello World"

by alexbispo on 2016-05-31 ▶

;; Note that the s "Vegeta" is returned as is, because there is no matching. (clojure.string/replace "Vegeta" #"Goku" "Gohan") "Vegeta"

by wdhowe on 2021-11-12 ▶

;; Removing characters, while ignoring case. (clojure.string/replace "Hello hello!" #"(?i)[h!]" "") ;=> "ello ello"

by wdhowe on 2025-12-31 ▶

;; Remove the last character in a string (clojure.string/replace "/my/dir/path/" #".$" "") ;=> "/my/dir/path"

Note by TejasBhatt

How can i replace "." with #"\s"

See also

• clojure.core/subs (3)
• clojure.string/split (4)
• clojure.string/replace-first (3)
• clojure.string/re-quote-replacement

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