java.util.regex.Matcher.replaceFirst() Method


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Description

The java.util.regex.Matcher.replaceFirst(String replacement) method replaces the first subsequence of the input sequence that matches the pattern with the given replacement string.

Declaration

Following is the declaration for java.util.regex.Matcher.replaceFirst(String replacement) method.

public String replaceFirst(String replacement)

Parameters

  • replacement − The replacement string.

Return Value

The string constructed by replacing the first matching subsequence by the replacement string, substituting captured subsequences as needed.

Example

The following example shows the usage of java.util.regex.Matcher.replaceFirst(String replacement) method.

package com.tutorialspoint;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MatcherDemo {
   private static String REGEX = "dog";
   private static String INPUT = "The dog says meow " + "All dogs say meow.";
   private static String REPLACE = "cat";

   public static void main(String[] args) {
      Pattern pattern = Pattern.compile(REGEX);
      
      // get a matcher object
      Matcher matcher = pattern.matcher(INPUT); 
      INPUT = matcher.replaceFirst(REPLACE);
      System.out.println(INPUT);
   }
}

Let us compile and run the above program, this will produce the following result −

The cat says meow All dogs say meow.
javaregex_matcher.htm
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