Pattern pattern() method in Java with Examples

The 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 used to get the same source expression.

Syntax:

public String pattern()

Parameters: This method does not accepts anything as parameter.

Return Value: This method returns the pattern’s source regular expression.

Below programs illustrate the pattern() method:
Program 1:

// Java program to demonstrate 
// Pattern.pattern() method 
  
import java.util.regex.*; 
  
public class GFG { 
    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 expressio of pattern 
        String RegularExpression = pattern1.pattern(); 
  
        System.out.println("Pattern's RegularExpression = "
                           + RegularExpression); 
    } 
} 

Output:

Pattern's RegularExpression = (.*)(for)(.*)?

Program 2:

// Java program to demonstrate 
// Pattern.compile method 
  
import java.util.regex.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a REGEX String 
        String REGEX = "(.*)(ee)(.*)?"; 
  
        // create the string 
        // in which you want to search 
        String actualString 
            = "geeks"; 
  
        // create pattern 
        Pattern pattern1 = Pattern.compile(REGEX); 
  
        // find the regular expressio of pattern 
        String RegularExpression = pattern1.pattern(); 
  
        System.out.println("Pattern's RegularExpression = "
                           + RegularExpression); 
    } 
} 

Output:

Pattern's RegularExpression = (.*)(ee)(.*)?

References:
https://docs.oracle.com/javase/10/docs/api/java/util/regex/Pattern.html#pattern()

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