regex
Regular expression match group example
This is an example of how to use a regular expression match group. Using a regular expression to group matches of a String with a pattern implies that you should:
- Compile a String regular expression to a Pattern, using
compile(String regex)
API method of Pattern. - Use
matcher(CharSequence input)
API method of Pattern to create a Matcher that will match the given String input against this pattern. - Use
find()
API method of Matcher to get the matches of the input with the pattern. - Use
group(int group)
API method to get the input subsequence captured by the given group during the previous match operation.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.core; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * REmatch -- demonstrate RE Match -> group() * */ public class MatchGroup { public static void main(String[] argv) { String pattern = "Q[^u]\d+\."; Pattern reg = Pattern.compile(pattern); String str = "Order QT300. Now!"; Matcher matcher = reg.matcher(str); if (matcher.find()) { System.out.println(pattern + " matches "" + matcher.group(0) + "" in "" + str + """); } else { System.out.println("NO MATCH"); } } }
Output:
Q[^u]d+. matches "QT300." in "Order QT300. Now!"
This was an example of how to use a regular expression match group in Java.