How To Use ArrayList With Array
Jun 2, 2014Something like ArrayList<Object>[] = new ArrayList<Object>[]();
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How To Use Array Instead Of ArrayList
Apr 3, 2014I'm making a program for my class's chapter on classes. I need to make a program that makes a grocery list using an array. Here's the assignment from the book.
Write a class named GroceryList that represents a list of items to buy from the market, and another class named
GroceryItemOrder that represents a request to purchase a particular item in a given quantity (example: four boxes
of cookies). The GroceryList class should use an array field to store the grocery items and to keep track of its size
(number of items in the list so far). Assume that a grocery list will have no more than 10 items. A GroceryList
object should have the following methods:
public GroceryList()
Constructs a new empty grocery list.
public void add(GroceryItemOrder item)
Adds the given item order to this list if the list has fewer than 10 items.
public double getTotalCost()
Returns the total sum cost of all grocery item orders in this list.
The GroceryItemOrder class should store an item quantity and a price per unit. A GroceryItemOrder object
should have the following methods:
public GroceryItemOrder(String name, int quantity, double pricePerUnit)
Constructs an item order to purchase the item with the given name, in the given quantity, which costs the given price
per unit.
public double getCost()
Returns the total cost of this item in its given quantity. For example, four boxes of cookies that cost 2.30 per unit
have a total cost of 9.20.
public void setQuantity(int quantity)
Sets this grocery item’s quantity to be the given value.
I have the assignment mostly done, but the JUnit test case our teacher gave us to test it tests add() an array instead of an array list. For this reason, I need to change my program to use an array. My code is below.
import java.util.*;
public class GroceryList {
private ArrayList<GroceryItemOrder> list;
int num;
public GroceryList() {
list = new ArrayList<GroceryItemOrder>(10);
[Code] .....
Cast 2D Array To ArrayList
Jan 23, 2014I ve got a 2d array and I want to cast it in an 2d arraylist. I ve create a function that cast an array to arraylist. My problem arises, when I tried to parse the whole 2d matrix to the arraylist. I use the following code:
Java Code: double sums[][] = computeSums(lab, projections);
ArrayList<ArrayList<Double>> lists = new ArrayList<ArrayList<Double>>();
ArrayList<Double> nu = new ArrayList<Double>();
System.out.println(sums[0].length);
for (int i = 0; i < sums.length; i++) {
ArrayList<Double> tt = toList(sums[i], nu);
lists.add(tt);
} mh_sh_highlight_all('java');
The problem is that only the first matrix sums[0] is copied to the 2d arraylist sums.length times. How is is possible to store all the different sums matrices to the arraylist??
Adding Element From Arraylist To Array
Sep 11, 2014So I'm trying to write a method which returns the number of vowel characters in arraylist. My idea is to convert the arraylist element by element to array each time iterating through the array counting the vowels of that element. When I started I immediately got an error(surprise, surprise). Excuse me if the problem is too simple, but I am very new to programming.
At line 9 I get the following error "Type mismatch: cannot convert from String to int". I want to get the element at this position, not to convert to int..
ublic class One {
public static void main(String[] args) {
ArrayList<String> bla = new ArrayList<String>();
bla.add("aaa");
bla.add("brr");
bla.add("unn");
}
public static ArrayList<String> averageVowels (ArrayList<String> list){
String[] arrListWord = list.toArray(new String[list.get(0)]);
return list;
}
}
Copy ArrayList Object Into Array
May 29, 2014package com.practice;
public class Car {
private String name; //name of the car
private String modelName; //Name of the model
private int year; //The year car was made in
private int speed=0;
[Code] ...
It wont let me copy it into a array is there any solution to this.
Copy Array Content To Arraylist
Apr 27, 2015I have a text file which contains to integer values I need to retrieve for each item (total of 56 items in the file). One is an item number, the other the weight ("Item: " + number + "Weight: " + weight). I am trying to build an array list that will add each set of data to it. I know that when I add the item array to the arraylist it is storing the array variable and not its contents, so is there a way to easily copy that data array to the array list?
ArrayList newInventory = new ArrayList();
int[] item = new int[2];
while(sc.hasNext()) {
String itemVal = br.readLine();
if(sc.hasNextInt()) {
item.add(sc.nextInt());
}
}
Creating ArrayList And Adding Item To Array
Nov 27, 2014Creating an Arraylist and adding item to that array, refer below code
ArrayList<String> sjarr = new ArrayList<String>();
Statement1:
String arritem1 = new String("First array item");
sjarr.add(arritem1);
Statement2:
String num = "text will decide";
sjarr.add(num);
Both adds the String item to array list but puzzling what makes the difference....
Add JPanels To ArrayList To Form Grid Like 2D Array
Sep 10, 2014i am to add jpanels to an arraylist such that it forms a grid like a 2d array. when i add the first colunm and have to iterate and store the next sequence of jpanels it still stores it in get(0), instead of get(1).
[/ temp.add(jPanel9);
temp.add(jPanel10);
temp.add(jPanel11);
temp.add(jPanel12);
temp.add(jPanel13);
temp.add(jPanel14);
temp.add(jPanel15);
[Code]...
ArrayList - Scan Array For Largest Number
Mar 24, 2014I need to create a program that uses ArrayList to store integers the user inputs, then scan the array for the largest number. I would also like the user to be able to exit this loop if the number 0 is entered.
As you can see below, I'm not sure how to correctly exit the do-while loop. I found this on another forum, but it does not work.
Java Code:
import java.util.*;
public class array {
public static void main(String [] args){
ArrayList<Integer> list = new ArrayList<Integer>();
[Code] ....
How To Randomly Assign Specific Values In Array Or ArrayList
Apr 3, 2015I'm trying to build a monopoly like game, and atm I'm trying to find way how to build the Community and Chance chest cards. so far, my logic is
1-create an ArrayList of cards with a given order
2-for a given number of times(for loop) generate 2 random numbers ,which will be the parameters for Collection.swap().
3-swap.
here's the code for the shuffler Button
shuffler.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
for(int i=0;i<shuffeledMessages.length;i++){
int randoma=(int)(Math.random()*4);
int randomb=(int)(Math.random()*4);
Collections.swap(myMessages,randoma,randomb);
}
}
});
For now things seem to work pretty ok, but I'm wondering if this is a good and efficient way to shuffle a card chest especially in case of large number of cards. plus, I'm not sure what would be a good loop count for effective shuffling, in my case I used i<arraylist.size
File Reading Values To Draw Image (java Graphics DrawString / ArrayList / Array)
Sep 13, 2014//compiler error I'm receiving
J:CS3Student Folder Review Lab #2APlusImage.java:41: error: cannot find symbol
xcor.add(read.nexInt());
[Code].....
Java Array Update Without Using ArrayList - Add Values And Update Size?
Feb 9, 2015I am trying to create an array list without using the built in arrayList class that java has. I need to start the array being empty with a length of 5. I then add objects to the array. I want to check if the array is full and if not add a value to the next empty space. Once the array is full I then need to create a second array that starts empty and with the length of the first array + 1.
The contents of the first array are then copied into the new array without using the built in copy classes java has and then the new array ends up containing 5 elements and one null space the first time round. The first array is then overwritten with the new array containing the 5 elements and the null space. The process then starts again adding values until the array is full which will be 1 more value then recreating the second array empty and the length of the first array + 1. This is my attempt at creating this but I have run into multiple problems where I get only the last value I added and the rest of the values are null:
public class MyArrayList {
public Object arrayList[];
public MyArrayList(Object[] arrayList) {
this.arrayList = arrayList;
[code]...
Create Own ArrayList Using Collection Without Implementing ArrayList Itself
Feb 28, 2014I'm trying to create my own arraylist using Collection. My program doesn't do anything. Obviously, I haven't a clue.
import java.util.Collection;
import java.util.Iterator;
public class MyArrayList<T> implements java.util.Collection<T> {
private int size = 4;
private T[] mArray;
public MyArrayList(String[] args) {
[Code] ....
Populating ArrayList Object With Nested ArrayList Object
Jul 8, 2014I have stumbled onto a problem with ArrayLists (not sure if nested ArrayList objects would be a more accurate description) ....
As simply put as I can describe it, I have an Inventory class which creates an ArrayList of a Product superclass, which has two subclasses, PerishableProduct and ItemisedProduct.
By default, the program is meant to have a starting inventory, which is why I have added them in the constructor
public class Inventory {
private List<Product> products;
public Inventory() {
addProduct(new Product("Frying pan", 15, 20));
addProduct(new PerishableProduct("Apple", 5.8, 30, 7));
addProduct(new ItemisedProduct("Cereal", 5.8, 0));
// this is where I am having problems. Wanting to add
// objects to the ItemisedProduct's ArrayList for cereal.
}
Within the ItemisedProduct subclass is yet another ArrayList which is meant to hold serial numbers.
public class ItemisedProduct extends Product {
private ArrayList<String> serialNumbers = new ArrayList();
public ItemisedProduct(String name, double price, int qty) {
super(name, price, qty)
[Code] .....
My problem is that I do not know how to populate the serialNumbers ArrayList from the Inventory class' constructor. Because technically, quantity is defined by how many serial numbers are created.
If Then For ArrayList?
Feb 26, 2015I think it's a problem with my if then else statements but I'm not sure?
package Hw1;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
public class ScrapWork {
public static void main(String[] args){
String[]Dalton={"Joe","William","Jack","Averell"};
[Code] .....
run:
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - illegal start of type
at Hw1.ScrapWork.main(ScrapWork.java:16)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)
Max And Min In ArrayList
Nov 14, 2014I have an ArrayList with String, String, Double.
From another class I would like to print minimum and maximum including the first String name.
I have tried with import java.util.Collections; but that didn't work.
Java Code:
ArrayList<List>list = new ArrayList<List>();
list.add(new List("Abc","Cba",1));
list.add(new List("Bca","Bca",5));
list.add(new List("Cba","AcB",2)); mh_sh_highlight_all('java');
I would like the result to look like:
Minimum: Abc 1
Maximum: Bca 5
How To Order Two ArrayList In One
Feb 14, 2015I have an ArrayList of employee and ArrayLsit of bosses, and I want to keep those people in a temporary ArrayList , then ordain alphabetically by name, to sort I use the interface comparator.
The problem comes when I will order 2 ArrayList(workers and bosses), because every time I call I use these functions or not is ordered (sortByNameAlphabetical())
public class Employee {
private String name;
public String getName() {
return name;
}
@Override
public String toString() {
return name ;
[Code]...
How To Add In Arraylist Of Object
Apr 7, 2015I'm creating a card game assignment... so i have an arraylist called cards that has 20 cards and every card has contains 2 objects, suit and the point Value.
I shuffled the deck, now i want to add half of it to player 1 and the rest of the cards goes to the bot or computer.
how can i add the cards to the player one arraylist and have all the information of the cards?
here is my Deck class code :-
public class Deck {
private ArrayList cards;
private int size;
private ArrayList player1;
private ArrayList bot;
[code]....
the problem i have is this one doesn't work
size = cards.size() / 2;
for (int i = 0; i < size - 1; i++) {
player1.add(cards.get(i));
}
for (int s = size; s < cards.size() - 1; s++) {
bot.add(cards.get(s));
}
Using GUI With Buttons And ArrayList
Sep 18, 2014Right now, i'm trying to do is when a user clicks on my GUI button, it would display a text of information on the button they selected. I'm using an arraylist of objects and i'm trying to input the function inside the mouse click function. But I'm not sure how to properly display that information. Here is my GUI code. I'm working on the raven button. I have animal interface, with a parent class of Bird, and child class of Raven. How I could display this correctly...
public class AnimalJF extends JFrame {
private JPanel contentPane;
private JTextArea textArea = new JTextArea();
/**
* Launch the application.
*/
public static ArrayList<Bird> Birdlist = new ArrayList<Bird>();
public static void main(String[] args) {
Birdlist.add(new Eagle());
[Code] .....
Reading From TXT To ArrayList?
Nov 21, 2014I am currently working on a program that will read from a .txt file to create an arraylist. I will be working with the objects in the list to perform computations and display the data. The .txt file is in the following format: lastName firstName hoursWorked hourlyRate
With no delimiters. I've messed with this thing way too much in the last 12 hours (only day off for the week ) so variable names etc have changed often. At present the error I am receiving is "error: constructor GrossPayService in class GrossPayService cannot be applied to given types".
import java.util.*;
import java.io.*;
import java.text.*;
class AryListObjects
{
public static void addEmployee(String firstName, String lastName, double hoursWorked, double hourlyRate)
{
ArrayList<GrossPayService> employees = new ArrayList<GrossPayService>();
[code]....
Delete From ArrayList
Dec 7, 2014I've this "program" that shall manage to register a dog, show a list of all registerd dogs and delete dogs from the list.. And I'm stuck at the latter one. So I've to classes, one for the dog and one for register/program. This is my main program
package hundRegister;
import java.util.Scanner;
import java.util.ArrayList;
public class HundProgram {
private static Scanner tangentbord = new Scanner (System.in);
private static ArrayList<Hund> hundlista = new ArrayList<>();
[Code] ......
So, when I enter a name on a dog that exist on my list, it just jumps down to } else { and write that dog can't be found even if I write the exact name on the dog.
I can't see what I'm doing wrong, been trying out different methods now.
How To Sort ArrayList
Jun 30, 2014How can i sort my ArrayList, which contains cars, with year and used year, i want to sort them first from year, and then from used year . what should i use?
View Replies View RelatedUsing Iterator To Add To Arraylist
Nov 12, 2014I am trying to add the contents of the iterator to an arraylist so I can do other stuff to it, however I am getting an error when I actually try adding it to the list, stating that
"The method add(Map.Entry<String,myObject>) in the type ArrayList<Map.Entry<String,myObject>> is not applicable for the arguments (myObject)"
Here is what I have tried doing:
Iterator<Map.Entry<String, myObject>> iterator = hash.entrySet().iterator();//hash is my HashMap object
ArrayList<Map.Entry<String, myObject>> list = new ArrayList<Map.Entry<String, myObject>>();
while(iterator.hasNext()){
Map.Entry<String, myObject> entry = iterator.next();
list.add(entry.getValue());//error here
}
Everything In ArrayList Written Twice
Mar 1, 2014I am trying to read a file into an array list, change some things about it, and then write it to another file. Files are getting written with what was read repeating a second time. I've tested the read method by having it print everything which goes into the ArrayList object. I then did the same with the write method which seems to write everything twice, as if everything is in the ArrayList twice, but I'm not sure how this is possible, since the read clearly did everything only once. Perhaps the ArrayList isn't the best collection to use for this purpose.
The read method:
Java Code:
private ArrayList<String> read(File in) {
String line;
ArrayList<String> data = new ArrayList<String>();
try {
BufferedReader r = new BufferedReader(new FileReader(in));
[code]....
Sorting Out ArrayList
Nov 26, 2014I have to sort out my ArrayList but cannot make it work. Here is
Java Code:
Collections.sort(this.users);
User poor = this.users.get(0);
User ritch = this.users.get((this.users.size()-1));
System.out.println("Poorest user has" + poor.getUsername() + poor.getBalance() );
System.out.println("Ritches user has " + ritch.getUsername() + poor.getBalance() + "
"); mh_sh_highlight_all('java');
The Collections.sort(this.users); does not work.
Compare All Objects In ArrayList To All Others But Not Self
Mar 15, 2015I have a ArrayList of objects of class called HockeyPlayer (ArrayList<HockeyPlayer>). A HockeyPlayer has a String name and int number of goals.
This is my current work for comparing each object in the list to every other and printing them to screen:
Iterator<HockeyPlayer> it = hockeyPlayersList.iterator();
while (it.hasNext()) {
HockeyPlayer singleHockeyPlayer = it.next(); //the first one encountered
// HockeyPlayer nextHockeyPlayer = it.next(); //the next one encountered
[Code]...
This of course produces some duplication in the print-out: These are the equal hockey players: Who Ever wears jersey. This type of employee is paid: true. This employee has post-secondary education: false. This employee's work is to play. This hockey player has scored 0 goals.
Jason Harrison wears jersey. This type of employee is paid: true. This employee has post-secondary education: false. This employee's work is to play. This hockey player has scored 0 goals.
These are the equal hockey players: Jason Harrison wears jersey. This type of employee is paid: true. This employee has post-secondary education: false. This employee's work is to play. This hockey player has scored 0 goals.
Who Ever wears jersey. This type of employee is paid: true. This employee has post-secondary education: false. This employee's work is to play. This hockey player has scored 0 goals.
How do I remove the duplication in the print-out?