Introduction

Java List interface is one of the most important members of the Java collection framework. The List index starts with 0 like usual arrays in Java. The List interface allows the addition of duplicates and nulls to the list. We can import the List using the following  statement:

import java.util.List;

Sample Listing

Below is a sample java program to capture strings of some length in a list and return the list of strings to the main program.

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

/*-------------------------------------------
 * Program description:
 * To learn how to write a java method that
 * processes a list of strings and returns
 * a sub list of string of specified length
 *
 ---------------------------------------------*/
public class ListOperationsExample {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // Emily Dickenson's poem two lines of
        // first stanza....
        List<String> list= new ArrayList<String>();
        list.add("I");
        list.add("will");
        list.add("tell");
        list.add("you");
        list.add("How");
        list.add("the");
        list.add("Sun");
        list.add("rose");
        list.add(",");
        list.add("A");
        list.add("ribbon");
        list.add("at");
        list.add("a");
        list.add("time");
        
        //Print list
        printList(list,"List");
        //Find string of length 4 in the stanza
        List<String> subList=stringsOfLength(list,4);
        
        //Print sub list
        printList(subList,"SubList");
    }

    /*-------------------------------------------
     * Method description:
     * stringsOfLength method returns a sub list
     * of strings that match the length specified
     * in the method call.
     ---------------------------------------------*/
    public static List<String> stringsOfLength(List<String> list,int n){
        List<String> returnList= new ArrayList<String>();
        int numberOfStrings = list.size();

        for(int i=0;i<numberOfStrings;i++){
            String listString = list.get(i);
            if(listString.length()== n){
                returnList.add(listString);
            }
        }
        return returnList;
    }
    
    /*-------------------------------------------
     * Method description:
     * printList method prints the list
     ---------------------------------------------*/
    public static void printList(List<String> list,String name){
        int numberOfStrings = list.size();
        System.out.print(name + " = [");
        for(int i=0;i<numberOfStrings;i++){
            System.out.print(" " + list.get(i));
        }
        System.out.println("]");
    }
}

Screenshot

 

 

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Java Tutorials

Java Tutorial on this website:

https://www.testingdocs.com/java-tutorial/

For more information on Java, visit the official website :

https://www.oracle.com/java/