All Questions
1,092
questions
1
vote
3
answers
77
views
Can an object belong to both an array and arraylist simultaneously in Java?
I am struggling to write a code sample where an object can belong to an array and arraylist simultaneously and where modifying in arraylist or the array changes the object? See example where I was ...
- 13
-1
votes
1
answer
44
views
Why is the second instantiation of the Player object rewriting the first in this Java program?
I am attempting to write a program that will allow a user to input four characteristics of a "Player" object and add that object to an array list of other Player objects. However, it seems ...
0
votes
1
answer
61
views
Mooc.fi Java 1 -Part07_07 Recipes
(Apologies for the formatting this is my first post)
I am looking at teaching myself Java through mooc.fi Java from the university of Helsinki,
I have been attempting this problem for 4 days straight ...
-1
votes
2
answers
77
views
Adding Coin Objects to Wallet Objects
I want to create a program where you're able to add and remove coins to a wallet, as well as show the total amount of money in the wallet. All through OOP. I've created a while loop where there are ...
- 7
1
vote
2
answers
160
views
C# Add List class to new List class without looping
I have a list of users returned in a class
My Class: List
public class EmployeeList
{
public int Emp_No { get; set; }
public string Sys_Prefix { get; set; }
public short Company_No { get; ...
0
votes
4
answers
109
views
Do I need unique names for all my objects in a list?
I am a first year Comp Sci student. For part of an assignmentI have for my Java class. I need to create a deck class that is an ArrayList containing Card objects.
Here is an example of a card object I ...
1
vote
0
answers
17
views
Can't add elements of another class (same package, public) to Array list. I was doing it before(im sure about it, can send code) but now i cant
I can create new Task object, ArrayList of the Task, but when I'm trying to add (early created or to create it when adding) Task object to List, it says that "Cannot access todo.Task."
I was ...
- 23
-1
votes
1
answer
76
views
How can i make a container of objects and how can i use it in other file
I basicly have an array list in my main class
public static void main(String[] args) {
List escenariosLi = new ArrayList<Escenario>();
String a = "";
escenariosLi.add(0,new ...
2
votes
3
answers
65
views
Split an List of objects based caseNumber into a new List of objects
I have an List of Messages objects. My message object consist of sender and CaseNumber. A SQL query is pulls all the messages into a list. In this list I have multiple of the same CaseNumber.
What ...
- 35
-1
votes
1
answer
57
views
How to add objects to list without having array brackets
I have a for loop in which I add some attributes to the object and at the end I need to have a string (to pass it as a query parameter)
I need
{"items":[{"itemsCode":"item1&...
- 17
0
votes
0
answers
25
views
Serialization and deserialization a list
I'm trying to write ArrayList to a file, and then read a random string from the ArrayList.
In the code, I'm trying to output at least the entire ArrayList from the file (in order to select a random ...
0
votes
5
answers
126
views
How to print a name by a given ID
var people = [
{name: 'John', id: [34, 44, 77]},
{name: 'Jose', id: [43, 54, 65]},
{name: 'Hanna', id: [56, 34, 98]}
];
var peopleFinder = people.filter(function(b){
return b.id === ...
0
votes
4
answers
550
views
Difference between Array and ArrayList<> in Java in terms of memory allocation?
I came accross an article which had a question-
Contiguous memory locations are usually used for storing actual values in an array but not in ArrayList. Explain.
https://www.geeksforgeeks.org/java-...
- 670
0
votes
1
answer
18
views
Trying to Compute the differences in two different ArrayLists of Objects with Instance Fields of Type Integer[JAVA]
package pckg;
import java.util.ArrayList;
import java.util.HashMap;
public class Tester
{
public static void main(String[] args)
{
ArrayList<TesterObj> my_first_objects = new ...
- 35
1
vote
1
answer
65
views
Flutter: How do I iterate a nullable table and add each row object to my object list
Problem: The method 'query' can't be unconditionally invoked because the receiver can be 'null'.
1 - I already checked that the _database is not null. How do I get around this?
2 - I'm not sure how to ...
- 113
-2
votes
2
answers
99
views
How to parse an objects with array index to object array with key value pairs
Convert this object Students object to one Students array
{"SubmitBy":"SK", "Students[0].name":"Jhon", "Students[0].age":"15", "...
-2
votes
1
answer
2k
views
How to display a list of objects as a JList in java swing?
We are asked to build a system in Java Swing no drag and drop and I cannot understand how to display a list of objects in a JList.
I have a GUI class that creates a JFrame, JPanel, and an empty JList ...
- 3
0
votes
3
answers
744
views
How to get data from List<Object[]> using java 8
Trying to get a data from DB using JPA. My Data format was like [[John,Wick,New York],[Walter,White,New Mexico]]
And am using below code the get the data from List<Object[]> and with iteration ...
- 233
0
votes
1
answer
77
views
Referencing an interface from ArrayList
I am having trouble understanding ((Edible)objects[i]).howToEat() at line 7 in the java code example given below. Edible is an interface which contains abstract method howToEat() and I understand that ...
2
votes
3
answers
204
views
Group an array of objects based on multi keys in Javascript?
I would like to share with you an existence problem
I have array as follows
const data = [
{
"countries": ["France", "USA", "Canada"],
"city": &...
- 95
-1
votes
2
answers
76
views
Java - from Array to linked ArrayList why it doesn't affect all int values?
I am studing Java, i have simple Array linked to ArrayList, it is fixed size i can change values inside array or list without change length.
So i tried to change all elements of the Array to see ...
- 25
0
votes
1
answer
38
views
how to return numbers by column from objects that have array list attribute
I have a class where I am creating different "Processes", an attribute of this class is an linked list of Integers. I have created different class objects and to make it easy to loop through ...
- 13
0
votes
2
answers
317
views
Java.lang.NumberFormatException when trying to read in a file, so I can use the data with my objects
I keep getting this error when I'm trying to read in a file and add the data to my objects. Can someone please help me? Here is the error:
Exception in thread "main" java.lang....
-1
votes
1
answer
24
views
I'm doing an assignment for my class where I need to create the functions below for a Path. I'm having trouble on the functions, am I overthinking it?
import java.awt.Point;
import java.util.ArrayList;
import java.util.Scanner;
public class Path
{
ArrayList<Point> pointOne;
ArrayList<Point> pointTwo;
public Path() {
...
0
votes
1
answer
53
views
JAVA Attribute of ArrayList<Object> not returning values
Class Hospital
package app;
import java.util.ArrayList;
import app.Department;
public class Hospital {
String hospitalId;
String hospitalName;
int departmentCount;
ArrayList<...
- 83
0
votes
2
answers
164
views
How to create an object from a file?
I've a file with a line that looks like this "Room,home,You are in your home"
I wanna read the file and then create an object (I have created a class called Room), what I wanna do now is ...
- 13
0
votes
2
answers
28
views
How to join the objects that have the name in common and do the sum of the values of the key value1 and value2. Javascript
I have an array with the following objects:
const arrayData = [
{name: 'John', car:'BMW', value1: 500, value2: 350},
{name: 'Paul', car: 'AUDI', value1: 290, value2: 200},
{name: 'John', car:'BMW', ...
- 7
1
vote
2
answers
63
views
Javscript/TypeScript: Find the key and append value as an array
I have an object which is like
[{
Date: 01/11/2022,
Questionnaire: [
{Title: 'Rating', Ans: '5' },
{Title: 'Comment', Ans: 'Awesome' }
]
},
{
Date: 01/11/2022,
Questionnaire: [
...
- 19
0
votes
2
answers
447
views
How do I return a specific object from an ArrayList?
So I'm trying to implement a method in a Grid class that returns the tile (which is an instance of the tile class) specified by two coordinates the user inputs. But I have no idea how to go about ...
- 3
-1
votes
1
answer
46
views
deleting duplicate objects from an arraylist
I have an array list consisting of objects defined in the class Result(date, name, grade). I have managed to sort the dataset. However I want there to be no duplicates, only the object with that has ...
- 1