How to find the Item with Minimum Number of Occurrences in a Vector in Java - Step by Step Examples

How to find the Item with Minimum Number of Occurrences in a Vector in Java ?

Answer

To find the item with the minimum number of occurrences in a Vector in Java, you can use a HashMap to count the occurrences of each item and then find the item with the minimum count.

✐ Examples

1 Find Item with Minimum Occurrences in a Vector of Strings

In this example,

We start by importing the necessary classes: java.util.Vector and java.util.HashMap.
We create a Vector named vec containing several string elements.
We create a HashMap named counts to store the occurrences of each string in the Vector. The keys of the HashMap will be the strings, and the values will be their counts.
We use a for loop to iterate through each element in the Vector. For each element, we increment its count in the HashMap using the getOrDefault method to handle missing keys.
We initialize two variables, minItem and minCount, to keep track of the item with the minimum occurrences and its count. minCount is initialized to Integer.MAX_VALUE to ensure any count will be lower initially.
We iterate through the HashMap to find the item with the lowest count. If we find an item with a count lower than minCount, we update minItem and minCount.
Finally, we print the item with the minimum number of occurrences to standard output using System.out.println.

Java Program

import java.util.Vector;
import java.util.HashMap;

public class Main {
    public static void main(String[] args) {
        // Step 2: Create a vector of strings
        Vector<String> vec = new Vector<>();
        vec.add("apple");
        vec.add("banana");
        vec.add("apple");
        vec.add("orange");
        vec.add("banana");
        vec.add("apple");
        vec.add("kiwi");
        
        // Step 3: Create a HashMap to count occurrences
        HashMap<String, Integer> counts = new HashMap<>();
        
        // Step 4: Count occurrences of each item in the vector
        for (String item : vec) {
            counts.put(item, counts.getOrDefault(item, 0) + 1);
        }
        
        // Step 5: Initialize variables to find the item with the minimum occurrences
        String minItem = "";
        int minCount = Integer.MAX_VALUE;
        
        // Step 6: Iterate through the HashMap to find the item with the lowest count
        for (HashMap.Entry<String, Integer> entry : counts.entrySet()) {
            if (entry.getValue() < minCount) {
                minItem = entry.getKey();
                minCount = entry.getValue();
            }
        }
        
        // Step 7: Print the item with the minimum occurrences
        System.out.println("Item with minimum occurrences: " + minItem);
    }
}

Output

Item with minimum occurrences: kiwi

2 Find Item with Minimum Occurrences in a Vector of Integers

In this example,

We start by importing the necessary classes: java.util.Vector and java.util.HashMap.
We create a Vector named vec containing several integer elements.
We create a HashMap named counts to store the occurrences of each integer in the Vector. The keys of the HashMap will be the integers, and the values will be their counts.
We use a for loop to iterate through each element in the Vector. For each element, we increment its count in the HashMap using the getOrDefault method to handle missing keys.
We initialize two variables, minItem and minCount, to keep track of the item with the minimum occurrences and its count. minCount is initialized to Integer.MAX_VALUE to ensure any count will be lower initially.
We iterate through the HashMap to find the item with the lowest count. If we find an item with a count lower than minCount, we update minItem and minCount.
Finally, we print the item with the minimum number of occurrences to standard output using System.out.println.

Java Program

import java.util.Vector;
import java.util.HashMap;

public class Main {
    public static void main(String[] args) {
        // Step 2: Create a vector of integers
        Vector<Integer> vec = new Vector<>();
        vec.add(1);
        vec.add(2);
        vec.add(3);
        vec.add(1);
        vec.add(2);
        vec.add(1);
        vec.add(4);
        vec.add(1);
        vec.add(5);
        vec.add(1);
        
        // Step 3: Create a HashMap to count occurrences
        HashMap<Integer, Integer> counts = new HashMap<>();
        
        // Step 4: Count occurrences of each item in the vector
        for (Integer item : vec) {
            counts.put(item, counts.getOrDefault(item, 0) + 1);
        }
        
        // Step 5: Initialize variables to find the item with the minimum occurrences
        int minItem = 0;
        int minCount = Integer.MAX_VALUE;
        
        // Step 6: Iterate through the HashMap to find the item with the lowest count
        for (HashMap.Entry<Integer, Integer> entry : counts.entrySet()) {
            if (entry.getValue() < minCount) {
                minItem = entry.getKey();
                minCount = entry.getValue();
            }
        }
        
        // Step 7: Print the item with the minimum occurrences
        System.out.println("Item with minimum occurrences: " + minItem);
    }
}

Output

Item with minimum occurrences: 3

Summary

In this tutorial, we learned How to find the Item with Minimum Number of Occurrences in a Vector in Java language with well detailed examples.

◀ Previous Next ▶

Java Tutorials

Java How-Tos

How to find the Item with Minimum Number of Occurrences in a Vector in Java - Step by Step Examples

How to find the Item with Minimum Number of Occurrences in a Vector in Java ?

Answer

✐ Examples

1 Find Item with Minimum Occurrences in a Vector of Strings

Java Program

Output

2 Find Item with Minimum Occurrences in a Vector of Integers

Java Program

Output

Summary

More Java Vectors Tutorials