Searching an element in Java ArrayList

This tutorial example will show you how to search an element in Java ArrayList in both case sensitive and case insensitive way.Case sensitive search

package com.roytuts.java.arraylist;

import java.util.ArrayList;
import java.util.List;

public class SearchInArrayList {

	public static void main(String[] args) {

		List<String> list = new ArrayList<>();
		list.add("A");
		list.add("B");
		list.add("C");
		list.add("D");
		list.add("E");

		boolean found = list.contains("a");
		System.out.println("element a : " + (found ? "found" : "not found"));

		found = list.contains("B");
		System.out.println("element B : " + (found ? "found" : "not found"));

		int index = list.indexOf("c");
		System.out.println("element c : "
				+ (index <= 0 ? "not found" : "found"));

		index = list.indexOf("C");
		System.out.println("element C : "
				+ (index <= 0 ? "not found" : "found"));

	}

}

Output

element a : not found
element B : found
element c : not found
element C : found

Case insensitive search

package com.roytuts.java.arraylist;

import java.util.ArrayList;
import java.util.List;

public class SearchInArrayListCaseInsensitive {

	private boolean contains(String str, List<String> list) {
		for (String s : list) {
			if (str.equalsIgnoreCase(s))
				return true;
		}
		return false;
	}

	private int indexOf(String str, List<String> list) {
		if (str != null) {
			for (int i = 0; i < list.size(); i++) {
				if (str.equalsIgnoreCase(list.get(i))) {
					return i;
				}
			}
		}
		return -1;
	}

	public static void main(String[] args) {
		SearchInArrayListCaseInsensitive insensitive = new SearchInArrayListCaseInsensitive();
		List<String> list = new ArrayList<>();
		list.add("A");
		list.add("B");
		list.add("C");
		list.add("D");
		list.add("E");

		boolean found = insensitive.contains("a", list);
		System.out.println("element a : " + (found ? "found" : "not found"));

		found = insensitive.contains("B", list);
		System.out.println("element B : " + (found ? "found" : "not found"));

		int index = insensitive.indexOf("c", list);
		System.out.println("element c : "
				+ (index <= 0 ? "not found" : "found"));

		index = insensitive.indexOf("C", list);
		System.out.println("element C : "
				+ (index <= 0 ? "not found" : "found"));

	}

}

Output

element a : found
element B : found
element c : found
element C : found

Thanks for reading.

Soumitra Roy Sarkar

I am a professional Web developer, Enterprise Application developer, Software Engineer and Blogger. Connect me on Roy Tutorials Twitter Facebook  Google Plus Linkedin

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