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Java program to search a pattern with case insensitive flag into the string using regular expression

Given a string, we have to search a pattern with case insensitive flag using regular expression.
Submitted by Nidhi, on June 12, 2022

Problem statement

In this program, we will create a string and search a pattern into the string using the regular expression with a case insensitive flag. Here, we used the compile() method of the Pattern class.

Source Code

The source code to search a pattern with a case insensitive flag into the string using regular expression is given below. The given program is compiled and executed successfully.

// Java program to search a pattern with flags into 
// the string using regular expression

import java.util.regex.*;

public class Main {
  public static void main(String[] args) {
    String str = "This is a string.";
    String regex = ".*IS.*";

    Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(str);

    boolean result = matcher.matches();

    if (result)
      System.out.println("Pattern matched in string.");
    else
      System.out.println("Pattern did not match in string.");
  }
}

Output

Pattern matched in string.

Explanation

In the above program, we imported the "java.util.regex.*" package to use the Pattern and Matcher classes. Here, we created a public class Main.

The Main class contains a main() method. The main() method is the entry point for the program. And, created a string str, initialized with "This is a string". Then we used the compile() and matcher() method to search the pattern with case insensitive flag into the string and printed the appropriate message.

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