Question

How to find occurrences of a substring in a string in Java

Answer 1

public class MyClass
{
    public static boolean isEmpty(String s) {
        return s == null || s.length() == 0;
    }
 
    public static int GetOccurrences(String str, String sub) {
        if (isEmpty(str) || isEmpty(sub)) {
            return 0;
        }
 
        return str.split(sub, -1).length - 1;
    }
 
    public static void main(String[] args)
    {
        String str = "DDEEAABCAEEEFDDAAEFFEEEEBA";
        String sub = "EE";
 
        int count = GetOccurrences(str, sub);
        
        System.out.println(count);
    }
}




/*
run:

4

*/

 

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Answer 2

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MyClass
{
    public static boolean isEmpty(String s) {
        return s == null || s.length() == 0;
    }
 
    public static int GetOccurrences(String str, String sub) {
        if (isEmpty(str) || isEmpty(sub)) {
            return 0;
        }
 
        Matcher matcher = Pattern.compile(sub).matcher(str);
 
        int count = 0;
        while (matcher.find()) {
            count++;
        }
 
        return count;
    }
 
    public static void main(String[] args)
    {
        String str = "DDEEAABCAEEEFDDAAEFFEEEEBA";
        String sub = "EE";
 
        int count = GetOccurrences(str, sub);
        
        System.out.println(count);
    }
}




/*
run:

4

*/

 

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Answer 3

public class MyClass
{
    public static boolean isEmpty(String s) {
        return s == null || s.length() == 0;
    }
 
    public static int GetOccurrences(String str, String sub) {
        if (isEmpty(str) || isEmpty(sub)) {
            return 0;
        }
 
        return (str.length() - str.replace(sub, "").length()) / sub.length();
    }
 
    public static void main(String[] args)
    {
        String str = "DDEEAABCAEEEFDDAAEFFEEEEBA";
        String sub = "EE";
 
        int count = GetOccurrences(str, sub);
        
        System.out.println(count);
    }
}




/*
run:

4

*/

 

70+ SQL courses for beginners and professionals