Method To Rearrange Elements In ArrayList?
Feb 24, 2015how to read and understand the API's. I've got an array list and I was wondering if there was a method that can randomly re arrange the elements in terms of their index positions.
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Method To Take Array Of Integers And Rearrange Numbers From Least To Greatest Using For Loops
Apr 22, 2014I'm making a method to take an array of integers and rearrange the numbers from least to greatest, using for loops.
I'm getting the error "java. lang. ArrayIndexOutOfBoundsException: 8,
Portion of the ArrayMethods class with the sorting method
Java Code:
public static Integer[] sortArray (Integer[] a)
{
int swap;
for (int i = 0; i < a.length; i++)
[code]....
Removing Elements From ArrayList
Aug 24, 2014Referring Code 1, the book says line 16 of the code removes the element "Three" but line 17 does not remove the element "Four" because of Statement 1. The question is does remove(Object o) method invoke the == or the equals method because statement 1 and 2 seem to be in conflict
Statement 1:
Two objects are equal if their object references point to the same object. (which is nothing but definition of ==)
Statement 2:
The author refers to Statement 1 and says "As mentioned earlier, the method remove compares the objects for equality before removing it from ArrayList by calling method equals."
Java Code:
import java.util.ArrayList;
public class DeleteElementsFromArrayList {
public static void main(String args[]) {
ArrayList<StringBuilder> myArrList = new ArrayList<>();
StringBuilder sb1 = new StringBuilder("One");
[Code] ....
2D Arraylist Replace Specified Elements
May 11, 2015I have a 2D arraylist, named as adjLists, which contains arraylists, containing values like these. Each two values are a "pair" and each third is a "flag" for the pair.
[278, 106, 0, 397, 36, 0, 59, 208, 0, 366, 221, 0]
[366, 221, 0, 397, 36, 0, 132, 390, 0, 278, 106, 0, 295, 0, 0]
I use code above to search for specified value pairs in these lists. vertexnum is the number of "sub arraylists" in adjLists.
for (int l = 0; l < vertexnum; l++) {
if (adjLists.get(l).get(0) == p.x && adjLists.get(l).get(1) == p.y) {
for (int h = 0; h < adjLists.get(l).size(); h += 3) {
for (int g = 0; g < vertexnum; g++) {
if ((vertexSprite[g].getX() + vertexSprite[g].getWidth() / 2) == adjLists.get(l).get(h)
[Code] ....
This code is to search exact values and replace their flag in every occurences. It can not find all the occurences of the values/pair in the lists, it replaces flag value only a few time. Value of score should be incremented with plus 1 after each found occurence, but this code increments it more than the number of matches.
Remove Multiple Elements From ArrayList?
Dec 27, 2014I have an ArrayList of tens of thousands of elements, and want to remove the items at a given set of sorted indices like {1,5,29,318,499,583}. It seems like this operation could be performed in linear time and space by first finding a cumulative sum of the shifts needed to move everything to their right positions and then shifting every item. On the other hand, removing and shifting one by one would seem to require many more shifts. Is there a way to do this in Java's ArrayList?
View Replies View RelatedHow To Print Out All Elements Inside ArrayList
Oct 5, 2014When this program runs it gives me
workbook.Contact@46e5590e
Number of contact: 1
The number of Contact that I input is just one when I run the program so the Number of contacts: 1 is correct, but it gives me workbook.Contact@46e5590e instead of printing out all the contacts stored inside the Contact class. Yes I do loop through the ArrayList and I also have a method inside the Contact class, the printNameAndPhone(), which prints out the name as well as the phone number but how do I incorporate the printNameAndPhone() method (located in the Contact class) inside the print() method (located inside the AddressBook class)???
Basically I'm asking how to access all the elements in the ArrayList<Contact> addressBook = new ArrayList<>();??My main class AddressBook
package addressbook;
import java.util.Scanner;
import java.util.ArrayList;
public class AddressBook {
[code]....
Methods For Partitioning Elements Of ArrayList
Feb 18, 2014I'm new to object oriented programming, my previous experiences have been in C. I was given an assignment to implement an operation to transform a list of data by creating a partitioning algoritm.
import java.util.*;
public class Partition {
public static void partitionWithSetGet ( List<String> theCollectionOfData ) {
int i, j;
while(i <= j){
int Result = theCollectionOfData.get(i).compareTo(pivot);
int Result = theCollectionOfData.get(j).compareTo(pivot);
[code]....
I want to grasp the this concept in greater detail, then I can use the Java API to figure out the syntax!
Accessing ArrayList Elements (Integer / String) And Put Them Into Hashtable
Mar 4, 2014I have a data structure such as: ArrayList<ArrayList<Integer,String>
The data looks as [[1,2,3] [3,4] [99,98,40,32,45,65,1]]
I am trying to access each element and put them into a hashtable such as:
Hashtable<Integer,String>
With what I am doing below I am getting an out of bound error but can't see any other way of accessing the element
public static void hash(ArrayList<ArrayList<String>> list)
{
for(int i = 0; i < list.size(); i++)
{
int cnt = 0;
for(int y = 0; y < list.size(); y++)
{
if (! hashMap.containsValue(list.get(i).get(y)))
{
hashMap.put(cnt, list.get(i).get(y));
cnt++;
}
...
Interpret Array Of Integers And Rearrange It
Nov 6, 2014This code is designed to interpret an array of integers and rearrange it so that the even numbers come before the odd. But it fails when I run it against my test?
public void evensLeft(int[] array) {
int myFun[] = new int[array.length];
int k = 0;
for (int i = 0; array.length-1 > i; i ++) {
if (array[i]%2==0) {
myFun[k] = array[i];
k++;
[Code] ....
JavaFX 2.0 :: How To Rearrange Components / Panes In SceneBuilder
Jun 26, 2014I am wondering how one rearranges an existing complex UI using scene builder. I have tried, for example, to add a scrollpane around another pane that was already nested deep in my layout and did not find a way to do this. Is this not supported or am I just not getting how it's done? Typical practical examples of this would be that one introduces a split pane around an existing part of the layout and moves existing controls/panes including all their configuration (resource keys, bindings etc.) into one part of the split pane to add more functionality into another.
View Replies View RelatedJava Recursion Method Is Not Working - Summing Elements In Array
Feb 2, 2015I am trying to sum up the elements of an array. When I test my code the sum is always off by one. For example if I input: 20, 40,30 it gives me 89 instead of 90.
This is what I have so far:
public static void main(String[args]){
int size = kbd.nextInt();
int [] myArray = new int [size]
//user inputs the elements of array
[Code]....
Declare Array Of 50 Elements Of Type Double - Print Output 10 Elements Per Line
Feb 5, 2015import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class array
{
public static void main(String[] args)
[Code] ...
Is there a way to write this, where, alpha is one array.
Write a program that declares an array "alpha" of 50 elements of type "double". Initialize the array so that the first 25 elements are equal to the square of the index variable and the last 25 elements are equal to three times the index variable. Output the array so that 10 elements per line are printed.
If I have an array of 50 integers, can I break that to read in lines of 10?
How To Create ArrayList Method
Jan 28, 2015Okay so here are the requirements.
Java Code:
/**
*The method creates an array list of integers and then prompts the user
* for an integer. As long as the user continues to enter anything other
* than -999, add the number to the array list.
*
* @return the array list of numbers
*/ mh_sh_highlight_all('java');
I've attempted this several times but am still struggling.
Add Elements To 2D Array Without Losing Elements
Jan 12, 2015I am trying to make a 2d array that keeps track of comparison counts. what I have so far works ok but writes over the previous elements with 0. can't seem to find where I am re-initializing the previous elements.
//this is one of my fill sort arrays
public void fillSelectionArray(int index, long countSum) {
//rand = new Random( );
//for ( int i = 0; i < listsize; i++) {
selectionList[ index -1] = countSum;
// }
[Code] ....
I know I am missing something just not sure what.
Creating A Method That Resembles ArrayList
Jan 21, 2015I'm writing a program that acts as a 'pocket' where the user is able to enter a kind of coin, such as, a quarter and the amount of quarters it has. I was assigned to do 3 different class, the Coin Class in which the coins and their values can be instatiated from, a Pocket Class, where I have to write a method that can add the coins of the user (basically the method would act like ArrayList .add() ) and the PocketClass tester. I have already written most of the code, but I am stuck as to how I could write the following method:
Java Code:
public void addCoin(String s, int i) {
// s is type of coin, you are using s to instantiate a Coin and get value
// i is number of coins, you are using i to keep adding value to the totalValuefor
} mh_sh_highlight_all('java');
Would I use a for-loop in order to keep track of the number of coins? I would use ArrayList but the assignment calls for creating a method similar to that of .add()
Using Java Arraylist With Menu Method
Apr 12, 20152 problems with this code:
How do I code this so that after the user has added to the arraylist 'theFruit' if they then press 'V' to view all fruit it includes the default fruit as well as the fruit they've added?
Also in the method 'AddFruit' it only allows me to add 2 fruit before printing. Why is this?
import java.util.ArrayList;
import java.util.Scanner;
public class StkOv {
public static void main(String[] args) {
TheMenu();
[Code] ....
How To Call On Arraylist That Is Passed In By A Method
Oct 11, 2014my arraylist is declared in my main method. A string that i will be calling on is declared in my main method as well. The arraylist and string is passed to a method outside the main. I am to search for the beginning of a string and end of the string, remove those items. Then i am to pass the string with the removed items to arraylist that is called in my main with an enhanced for loop. The for loop then displays what is needed from the string and the method i created. I will posting an example of my main and method that is used in my program.
public class ExampleUrl {
public static void main(String[] args) throws MalformedURLException, IOException {
ArrayList<String> urlList = new ArrayList();
String url = "";
[Code].....
Method Rectangle - Loop With ArrayList
Jan 14, 2014I have created a method Rectangle and added a loop in my class Resizer (MouseAdapter) but impossible to resize the rectangles of the arraylist independantly !
class Rectangle extends Rectangle2D.Float{
private String name;
public Rectangle(float x, float y, float width, float height, String name) {
setRect(x, y, width, height);
this.name = name;
[Code] .....
Searching ArrayList - Cannot Find Symbol For Search Method
Mar 30, 2014This is the code fragment I have for searching my ArrayList. Now, each contact is stored in the ArrayList with five elements (first name, last name, etc.) and they're Strings. The error I get when I try to compile my program lies within this code fragment. It says it cannot find the symbol for the search method. I'm not quite sure what to do with this error.
int foundIndex = SAAddressBook.search(aBook);
System.out.println();
if (foundIndex > -1)
aBook.get(foundIndex).displayContact();
else {
System.out.println("No Entry Found");
}
ArrayList Contains Method Does Not Work On User-defined Data Types
Sep 1, 2014I am trying to remove the duplicate elements from ArrayList using .contains() if elements are primitive datatype it works but user-defined datatype does not work.
public class UserBean {
String name;
String address;
public String getName() {
return name;
[code]....
Code Java Method That Accepts ArrayList Of Integers And Integer
Mar 18, 2014How do I code this without having the need to use iterator? Code a Java method that accepts an ArrayList of integers and an integer. The method should delete all elements in the array list exactly divisible by the integer and return the number of remaining elements.
View Replies View RelatedQuick Sort Method For ArrayList Of Strings - Compiler Error
Sep 14, 2014So I'm trying to implement a quick sort method for an ArrayList of Strings and right now I'm getting the compiler error message: Exception in thread "main" java.lang.OutOfMemoryError: Java heap space. I don't know what that error means nor how to fix it. I've marked in my code where the error seems to be occurring.
import java.util.ArrayList;
public class quickSort
{
// constructor
public quickSort()
[code]....
How To Implement Collections Binary Search Method On ArrayList Of Custom Objects
May 11, 2012I'm doubted regarding the implementation of Collections.binarySearch() method on an ArrayList of objects of a custom class Movie.
Here is the movie class :
public class Movie implements Comparable<Movie> {
String movieName;
String rating;
String director;
String theme;
[Code] .....
The sort/binarySearch in searchByMovieName function is done with natural sorting (and Comparable Interface in Movie class). I mean no comparators involved here. And the comparator that I used for sorting/binarySearching on Movies Director attribute in searchByMovieDirector function is :
public class MovieDirectorComparator implements Comparator<Movie> {
public int compare(Movie movie1, Movie movie2) {
return movie1.getDirector().compareToIgnoreCase(movie2.getDirector());
}
}
But I was not able to implement binarySearch ?? How to implement the binarySearch here. I have google to see only binarySearch working on Arrays or probably ArrayList of String only, but not on ArrayList of custom objects.
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] ....
How To Add Elements To A Map
Mar 13, 2015I have a requirement to add elements to a map. But for, First iteration it inserts fine and for next iteration elements are overrided.
I am just wondering if there were append() in map or in any collections?
Why Not Getting All The Elements In TreeSet
Aug 1, 2014public void createPersons() {
Random rand = new Random();
for(int index = 0; index < persons.length; index++) {
Person person = new Person(rand.nextInt(maxAge), persons[index]);
setOfPersons.add(person);
[Code] ....
setOfPersons is a TreeSet, persons[] is an array of strings that contains 10 names. Why printPersons() prints only the half names of setOfPersons?
Note. I do get the size of the TreeSet as 10...