Why can't I replace ":)"

Question

I can't seem to replace a string of ":)" to something else, here is my code:

if(message.contains(":)")) message = message.replaceAll(":)", replacement);

This is the error:

Exception in thread "Listen" java.util.regex.PatternSyntaxException: Unmatched closing ')'
near index 0
:)
^

What should I do?

http://stackoverflow.com/questions/9279893/how-to-replace-brackets-in-strings — Suvarna Pattayil, Jan 12 '14 at 14:58

arshajii · Accepted Answer · 2014-01-12T15:03:08.050

8

Don't use replaceAll(); use replace() when you want to replace literal strings:

message.replace(":)", replacement)

replaceAll() deals with regular expressions, in which ) has a special meaning, hence the error.

edited Jan 12 '14 at 15:03

answered Jan 12 '14 at 14:57

arshajii

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+1 I hate when ppl do that, downvoting with no comment espcially when they are wrong! – giorashc Jan 12 '14 at 14:59
1

Why would someone downvote this? – Rohit Jain Jan 12 '14 at 15:00
thanks a lot, this worked! – FFlaser Jan 12 '14 at 15:04
@user3187526 Glad I could help. Don't forget to [accept an answer](http://meta.stackexchange.com/questions/5234/how-does-accepting-an-answer-work/5235#5235). – arshajii Jan 12 '14 at 15:04
BTW, `replace()` function is backed by Pattern class, not a normal loop append. – nhahtdh Jan 12 '14 at 17:18

score 2 · Answer 2 · answered Jan 12 '14 at 14:58

2

You must escape ) in regexen:

message = message.replaceAll(":\\)", replacement);

This is because ) has special meaning (capture groups), so you have to "tell" regex that you just want a literal ).

answered Jan 12 '14 at 14:58

tckmn

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Maroun · Answer 3 · 2014-01-12T15:01:58.210

1

Write:

message.replaceAll(Pattern.quote(":)"), replacement);

String#replaceAll accept a regex, not a regular String. ) has a special meaning in regex, using quote will cause treating :) as the String :) and not the regex.

If you don't want to use Pattern#quote, you should escape the ) by \\. Note that escaping a regex is done by \, but in Java, \ is written as \\.

If you don't like any of the mentioned, use String#replace that doesn't accept a regex, and you're fine.

edited Jan 12 '14 at 15:01

answered Jan 12 '14 at 14:57

Maroun

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@arshajii Fixed. Thanks. – Maroun Jan 12 '14 at 14:59
God.... give someone opportunity to fix his mistake................ – Maroun Jan 12 '14 at 15:01
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@DoorknobofSnow Using a `#` is a common way to separate a class name and a method/property name when referencing a method/property (typically in docs). – ajp15243 Jan 12 '14 at 15:03
@ajp15243 I know, but before the edit it was `message.replaceAll(Pattern#quote(":)"), replacement);` (now fixed) – tckmn Jan 12 '14 at 15:03
@DoorknobofSnow Ah I see, well the question went through so many edits I didn't catch that lol. – ajp15243 Jan 12 '14 at 15:04

Why can't I replace ":)"

3 Answers3