Java Pattern pattern() Method
Last Updated :
10 Jan, 2025
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pattern() method of the Pattern class in Java is used to get the regular expression which is compiled to create this pattern. We use a regular expression to create the pattern and this method is used to get the same source expression.
Example 1: Using the pattern() method to check the regex pattern passed for pattern matching.
// Java program to demonstrate
// Pattern.pattern() method
import java.util.regex.*;
public class Geeks
{
public static void main(String[] args)
{
// create a REGEX String
String REGEX = "(.*)(for)(.*)?";
// create the string in which you want
// to search
String actualString = "code of Machine";
// create pattern
Pattern pattern1 = Pattern.compile(REGEX);
// find the regular expression of pattern
String RegularExpression = pattern1.pattern();
System.out.println("Pattern's RegularExpression = "
+ RegularExpression);
}
}
Output
Pattern's RegularExpression = (.*)(for)(.*)?
Syntax
public String pattern()
- Parameters: This method does not accepts anything as parameter.
- Return Value: This method returns the pattern's source regular expression.
Example 2: Using the pattern() method in conjunction with a Matcher.
// Java program to demonstrate the usage of
// regular expressions in pattern matching
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Geeks
{
public static void main(String[] args)
{
// Input strings to match the regex against
String input1 = "The quick brown fox jumps over the lazy dog";
String input2 = "The quick red fox jumps over the lazy dog";
// Regex pattern to match case-insensitive 'the'
String regex = "(?i)the";
// Compile the regex pattern
Pattern pattern = Pattern.compile(regex);
// Create matchers for both input strings
Matcher matcher1 = pattern.matcher(input1);
Matcher matcher2 = pattern.matcher(input2);
// Find and print all matches in input1
while (matcher1.find()) {
System.out.println("Match 1: " + matcher1.group());
}
// Find and print all matches in input2
while (matcher2.find()) {
System.out.println("Match 2: " + matcher2.group());
}
}
}
Output
Match 1: The Match 1: the Match 2: The Match 2: the
