Java replaceAll function of string does not replace [duplicate]

This question already has answers here: Closed 11 years ago.

Possible Duplicate:

Wrong output using replaceall

If I have string:

String test = "replace开发者_如何学C()thisquotes";

test = test.replaceAll("()", "");

the test result is still: test = "replace()thisquotes"

so () is not replaced.

Any ideas?

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You don't need regex, so use:

test.replace("()", "")

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As others have pointed out, you probably want to use String.replace in this case as you don't need regular expressions.

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For reference however, when using String.replaceAll, the first argument (which is interpreted as a regular expression) needs to be quoted, preferably by using Pattern.quote:

String test = "replace()thisquotes";

test = test.replaceAll(Pattern.quote("()"), "");
//                     ^^^^^^^^^^^^^

System.out.println(test);  // prints "replacethisquotes"

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The first argument of replaceAll function is a regular expression. "(" character is a special character in regular expressions. Use this :

public class Main {

   public static void main(String[] args) {
      String test = "replace()thisquotes";
      test = test.replaceAll("\\(\\)", "");
      System.out.println(test);
   }
}

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You have to escape () as these are characters reserved for regular exressions:

String test = "replace()thisquotes";
test = test.replaceAll("\\(\\)", "");

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test = test.replaceAll("\\(\\)", "").

Java replace all uses regular expressions so in your example "()" is an empty group, use escape character '\".

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You have to quote your String first because parenthesis are special characters in regular expressions. Have a look at Pattern.qutoe(String s).

test = test.replaceAll(Pattern.quote("()"), "");