How to use Regex quantifiers - part 2 | Java Regex | Java Regular Expressions | Regex in java

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How to use Regex quantifiers - part 2 | Java Regex | Java Regular Expressions | Regex in java

RegexDemo1.java

import java.util.regex.Pattern;


public class RegexDemo1
{
    public static void main(String[] args)
    {
        System.out.println("X{n} = X occurs n times only");  
        /*
         * Parameters:
         * 
         * regex - The expression to be compiled
         * 
         * input - The character sequence to be matched
         * 
         * Returns:
         * 
         * whether or not the regular expression matches on the input
         * 
         */
        System.out.println(Pattern.matches("a{3}", "aaa"));//true (a should come 3 times)
        System.out.println(Pattern.matches("a{3}", "aaaaaa"));//false (a should come 3 times)
        System.out.println(Pattern.matches("a{3}", "aa"));//false (a should come 3 times) 
        System.out.println(Pattern.matches("a{3}", "a"));//false (a should come 3 times)
        System.out.println(Pattern.matches("a{3}", "bbb"));//false (a should come 3 times)
    }

}

Output

X{n} = X occurs n times only
true
false
false
false
false

RegexDemo2.java

import java.util.regex.Pattern;

public class RegexDemo2
{
    public static void main(String[] args)
    {
        System.out.println("X{n,} = X occurs n or more times");  
        /*
         * Parameters:
         * 
         * regex - The expression to be compiled
         * 
         * input - The character sequence to be matched
         * 
         * Returns:
         * 
         * whether or not the regular expression matches on the input
         * 
         */
        System.out.println(Pattern.matches("a{3,}", "aaa"));//true (a can come 3 times or more)
        System.out.println(Pattern.matches("a{3,}", "aaaaaa"));//true (a can come 3 times or more)
        System.out.println(Pattern.matches("a{3,}", "aa"));//false (a can come 3 times or more) 
        System.out.println(Pattern.matches("a{3,}", "a"));//false (a can come 3 times or more)
        System.out.println(Pattern.matches("a{3,}", "bbb"));//false (a can come 3 times or more)
    }

}

Output

X{n,} = X occurs n or more times
true
true
false
false
false

RegexDemo3.java

import java.util.regex.Pattern;

public class RegexDemo3
{
    public static void main(String[] args)
    {
        System.out.println("X{y,z} = X occurs at least y times but less than or equal to z times");  
        /*
         * Parameters:
         * 
         * regex - The expression to be compiled
         * 
         * input - The character sequence to be matched
         * 
         * Returns:
         * 
         * whether or not the regular expression matches on the input
         * 
         */
        System.out.println(Pattern.matches("a{3,6}", "aaa"));//true (a can come 3 times or <= 6 times)
        System.out.println(Pattern.matches("a{3,6}", "aaaaaa"));//true (a can come 3 times or <= 6 times)
        System.out.println(Pattern.matches("a{3,6}", "aaaaaaaaaaa"));//false (a can come 3 times or <= 6 times)
        System.out.println(Pattern.matches("a{3,6}", "aa"));//false (a can come 3 times or <= 6 times)
        System.out.println(Pattern.matches("a{3,6}", "a"));//false (a can come 3 times or <= 6 times)
        System.out.println(Pattern.matches("a{3,6}", "bbb"));//false (a can come 3 times or <= 6 times)
    }

}

Output

X{y,z} = X occurs at least y times but less than or equal to z times
true
true
false
false
false
false

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RegexDemo_Quantifier_number_of_times.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RegexDemo_Quantifier_number_of_times

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/950c9f162cb72194a90be45ab9293fca2b84f41c/BasicJava/RegexDemo_Quantifier_number_of_times/?at=master

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