Iterate Over ArrayList Elements

In the previous post, we have seen how to find the size of ArrayList.In this post, we will see how to iterate over ArrayList elements.

There are 4 ways to iterate over the ArrayList.

• For Loop
• For each loop
• While loop
• Itearator

Let’s understand them one by one. We use get method to fetch the value.

For Loop:

import java.util.ArrayList;

public class ArrayListEx {

	public static void main(String[] args) {
		ArrayList<String> cityList = new ArrayList<String>();
		cityList.add("Bangalore");
		cityList.add("Delhi");
		cityList.add("Pune");
		cityList.add("Noida");
		
		int totalSize = cityList.size();
		
		for(int i=0;i<totalSize;i++){
			System.out.println(cityList.get(i));
		}
	}
}

Output:

For Each Loop:

Syntax:

for(DataType variable : collections)

Example:

import java.util.ArrayList;

public class ArrayListEx {

	public static void main(String[] args) {
		ArrayList<String> cityList = new ArrayList<String>();
		cityList.add("Bangalore");
		cityList.add("Delhi");
		cityList.add("Pune");
		cityList.add("Noida");
				
		for(String city : cityList){   //For each loop
			System.out.println(city);   
		}
	}
}

Output: 

While Loop:

import java.util.ArrayList;

public class ArrayListEx {

	public static void main(String[] args) {
		ArrayList<String> cityList = new ArrayList<String>();
		cityList.add("Bangalore");
		cityList.add("Delhi");
		cityList.add("Pune");
		cityList.add("Noida");
		
		int count =0;
		
		while(cityList.size() > count){
			System.out.println(cityList.get(count));
			count++;
		}
	}
}

Output:

Iterator:

It uses method ‘hasnext()‘ to check the element existence and ‘next()‘ to display the element.

import java.util.ArrayList;
import java.util.Iterator;

public class ArrayListEx {

	public static void main(String[] args) {
		ArrayList<String> cityList = new ArrayList<String>();
		cityList.add("Bangalore");
		cityList.add("Delhi");
		cityList.add("Pune");
		cityList.add("Noida");
		
		Iterator iter = cityList.iterator();
		
		while(iter.hasNext()){
			System.out.println(iter.next());
		}
	}
}

Output: