CODEWITHSUNDEEP
stringclojure
Sergey
Sergey

Reputation: 11918

clojure remove last entrance of pattern in string

I have a string and some pattern at the end of the string. How can I remove this pattern exactly at the end of the word but nothing more even if it exists in the beginning or in the middle. For example, the string is

PatternThenSomethingIsGoingOnHereAndLastPattern

and I need to remove the "Pattern" at the end so that result would be

PatternThenSomethingIsGoingOnHereAndLast

How can I do that?

Upvotes: 5

Views: 5184

Answers (3)

sloth
sloth

Reputation: 101122

You can use replaceAll

=> (.replaceAll "PatternThenSomethingIsGoingOnHereAndLastPattern" "Pattern$" "")
"PatternThenSomethingIsGoingOnHereAndLast"

or clojure.string/replace

=> (clojure.string/replace "PatternThenSomethingIsGoingOnHereAndLastPattern" #"Pattern$" "") "PatternThenSomethingIsGoingOnHereAndLast"

Upvotes: 8

topcat3
topcat3

Reputation: 2642

Everything you need here I do believe

(def string "alphabet")
(def n 2)
(def m 4)
(def len (count string))

;starting from n characters in and of m length;
(println
 (subs string n (+ n m)))              ;phab
;starting from n characters in, up to the end of the string;
(println
 (subs string n))                      ;phabet
;whole string minus last character;
(println
 (subs string 0 (dec len)))            ;alphabe
;starting from a known character within the string and of m length;
(let [pos (.indexOf string (int \l))]
  (println
   (subs string pos (+ pos m))))     ;lpha
;starting from a known substring within the string and of m length.
(let [pos (.indexOf string "ph")]
  (println
   (subs string pos (+ pos m))))      ;phab

Upvotes: 0

Michiel Borkent
Michiel Borkent

Reputation: 34840

Your question doesn't specify if the pattern has to be a regex or a plain string. In the latter case you could just use the straightforward approach:

(defn remove-from-end [s end]
  (if (.endsWith s end)
      (.substring s 0 (- (count s)
                         (count end)))
    s))

(remove-from-end "foo" "bar") => "foo"
(remove-from-end "foobarfoobar" "bar") => "foobarfoo"

For a regex variation, see the answer of Dominic Kexel.

Upvotes: 10

Related Questions