Accessing Values From ArrayList
Nov 27, 2014
I'm a total newbie to Java, and until now all I've done was draw some shapes and flags. I'm struggling to understand the code I've been given. I need to access values stored in an ArrayList within another class. Here are the two classes Seat and Mandate:
package wtf2;
import java.util.*;
public class Seat {
public int index;
public String place;
public int electorate;
[Code] ....
The main class contains code that feeds data from 2 text files into Seat and Mandate. From there I managed to access the date in Seat (at the end):
package wtf2;
import java.io.*;
import java.util.*;
public class CW2 {
public static void main(String[] args)throws Exception {
[Code] ....
Now,instead of getting just the mp for Edinburgh South I need to get the vote values, compare them to each other, take the second biggest and display the associate party value. How to access data from that Array to get started at least.
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Oct 19, 2014
What I want to do is this, this is my first class:
public class Footballer {
int goals;
String surname= "";
String team="";
private static int counter=0;
private int dres;
}
(this is just the header of the class... And this is my second class, which contains an ArrayList of the first class:
public class FootballTeam{
String teamname="";
String league="";
ArrayList<Footballer> f;
}
And this is my third class which contains an ArrayList of the second class:
public class FootballLeague{
String leaguename="";
ArrayList<FootballTeam> ft;
}
What I want to do is, know how many of footballers are there in the league? Meaning how many of "f"s are in the "ft"... I remember from C++ it was easy, you just did it something like this: ft.f[i]; (where i is a position), then you'd go through each of them, if you wanted to do something with them, or just ask for it's length, if you needed to know how much footballers are there.
I'm trying this method to get the size of the array in the 2nd class, from the 3rd class (containing an ArrayList of classes of 2nd class, but no luck:
int counter=0;
for(int i=0;i<this.ft.size();i++) {
counter+=this.ft[i].f.size();
}
I'm getting this: Array required, but ArrayList<FootballTeam> found ---
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Oct 19, 2014
What I want to do is this, this is my first class:
Java Code:
public class Footballer {
int goals;
String surname= "";
String team="";
private static int counter=0;
private int dres;
} mh_sh_highlight_all('java');
(this is just the header of the class, just how it looks)...
And this is my second class, which contains an ArrayList of the first class:
Java Code:
public class FootballTeam{
String teamname="";
String league="";
ArrayList<Footballer> f;
} mh_sh_highlight_all('java');
And this is my third class which contains an ArrayList of the second clas:
Java Code: public class FootballLeague{
String leaguename="";
ArrayList<FootballTeam> ft;
} mh_sh_highlight_all('java');
What I want to do is, know how many of footballers are there in the league? Meaning how many of "f"s are in the "ft"... I remember from C++ it was easy, you just did it something like this: ft.f[i]; (where i is a position), then you'd go through each of them, if you wanted to do something with them, or just ask for it's length, if you needed to know how much footballers are there.
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Oct 14, 2014
Scanner in = new Scanner(System.in);
ArrayList<rand> selectedRand = new ArrayList<Rand>();
selectedRand.add(new Rand(in.nextLine()));
I have created the most minimal code for creating an array list. I was wondering what the basic syntax of accessing objects methods that are within an Array List. So if I was to trying and get a method such as [.returnValue,] how would this look within a Rand object that is declared in a Array List Since you cannot simply declare a new Rand object and say:
newRandObject.returnValue();
And you must go through the actual slotted portion of the array list. I have searched the web and my text book for an example however none are provided.
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Mar 4, 2014
I 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++;
}
...
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Apr 15, 2013
I am trying to create a method in BlueJ which needs the values from a Map to be copied into a List so I can use the List methods min() and max(). Here is the method I have created so far:
public String findNamesInPageRange()
{
int minOfRange = Integer.parseInt(OUDialog.request("Input number for start of range"));
int maxOfRange = Integer.parseInt(OUDialog.request("Input number for end of range"));
String foundIt = null;
for(String eachKey : bookIndex.keySet()) {
List<Integer> pageList = new ArrayList<>(); //Cannot access values from a map using this List
if((minOfRange >= Collections.min(pageList)) && (maxOfRange <= Collections.max(pageList))) {
foundIt = eachKey;
}
}
return foundIt;
}
As can be seen there is a comment showing where my problem lies.
The Map is coded as Map<String, Set<Integer>> bookIndex = new TreeMap<>();
Ive tried using bookIndex.values() as the argument of the List but I get an incompatible type error
So, how can this problem I am having be resolved?
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Apr 22, 2013
I am trying code a method where each key in a Map is iterated through keySet in a for-each loop but while each key is being accessed I need to also access its values where the values are of the type Set<Integer>. The Map is named bookIndex and I have tried using bookIndex.values() but this accesses all the values of the Map and not just the values of the key being presently accessed. Ive tried using a List to do this but was advised that this was not needed in another thread (Accessing Map values through a List). Ive tried creating a Set to contain these values but bookIndex.values() does not do it.
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Feb 24, 2014
I've tried a couple ways to do it, and they don't work. I'm aiming for functionality like I got with the regular for loop, but from an enhanced for loop. Is this simply beyond the scope of an enhanced for loop, or am I just not getting the right syntax?
TestObject to1 = new TestObject("first", 11);
TestObject to2 = new TestObject("second", 12);
TestObject to3 = new TestObject("third", 13);
TestObject to4 = new TestObject("fourth", 14);
TestObject to5 = new TestObject();
List<TestObject> testList;
testList = new ArrayList<TestObject>();
[code]....
The TestObject class is simply an int and a String, with getters getInt and getString. It all works fine with the regular for loop.
edit: I should probably mention that I know what I have in the enhanced for loop now will only display the class name and the hash. I've tried adding the .getString and .getInt, and tried a few other ways to make it work. I just reverted to this because it compiles and runs
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Nov 4, 2014
I am trying to create a method for my "ticketmachine" object that counts ticket objects in an arraylist of "ticket" objects with a specified field "route". The method works if i change the field type of the ticket class to public, however according to the homework task "route" of the ticket class needs to remain a private field.
Here is my code for the method.
public int countTickets(String route) //HAD TO CHANGE Ticket class FIELD "ROUTE" TO PUBLIC!!!!
{
int index = 0; //returns the number of Ticket objects in the machine with the specified "route".
int ticketCounter = 0;
while (index < tickets.size())
[Code] ....
Is my general approach to the problem wrong? also is there a way to access a private field?
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Apr 9, 2014
What does the line Console[] conList mean? How am I going to access the string values in class consolelist?
class ConsoleInfo
{
private String conTitle;
private double conPrice;
private int conQty;
private String conPic;
[Code] .....
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Apr 27, 2015
This code currently just prints out the memory for the objects. What I am doing that it obviously wrong?
import java.util.ArrayList;
import java.util.List;
public class deck extends Card {
public final String[] SUITS = { "Heart", "Diamond", "Clubs", "Spade" };
ArrayList<Card> deck = new ArrayList<Card>();
[Code] .....
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Jun 12, 2014
I declared an arraylist in doPost method and i passed it to the another jsp. The problem is arraylist contains old values for every new request.
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Mar 23, 2015
I am facing difficulties in identifying the proper way to add the selected colors of cards into an arraylist. I am having an arraylist which is:
Java Code: private List<String> selectedCars = new ArrayList<String>(); mh_sh_highlight_all('java'); And one more for the carColors:
Java Code: private List<String> carColors = new ArrayList<String>(); mh_sh_highlight_all('java');
The selectedCards array will store the selected cars ['TOYOTA','MAZDA','NISSAN'] as per the selection from the user.For certain types, there is one default color which is 'Black', however for some of them, the user can select different colors.(ex. if selection is 'Toyota')
Java Code:
String carColor="";
String toyotaColor=""; // The value will be retrieved from the form once the user selected the color
if (selectedCars.contains("MAZDA"))
{
carColor="Black";
}
else if (selectedCars.contains("TOYOTA"))
{
carColor=toyotaColor;
[code]....
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May 5, 2014
I'm having an issues with adding integer values to a string list. The question is asking me "the method should iterate over runners, and for each runner generate a random number between 90 and 180 (inclusive) which should be used to set the time (in minutes) for that runner."
I have been able to get the random number and iterating over the runner arraylist but I haven't been able to figure out how to add the values generated into the runners list. I am also using BlueJ.
Here's the whole code I have at the moment:
import java.util.*;
import java.io.*;
import ou.*;
import java.util.Random;
/**
* Write a description of class MarathonAdmin here.
*/
public class MarathonAdmin {
// instance variables - replace the example below with your own
[Code] .....
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Nov 4, 2014
I am creating a shopping list, with each element and object called product from the Item attribute class. Each product object has a description, price, and priority. From user input, I am able to create each product object, and then .add to my arraylist. I know that it successfully adds because I have it printed in each iteration of the do-while loop. Once the user indicates they want to quit, the loop ends. I then want to print each description, price, and quantity but this for loop will only print the last element over and over. Here is what I have:
ArrayList <ItemAttribute> list = new ArrayList<ItemAttribute>();
Scanner keyboard = new Scanner(System.in);
ItemAttribute product = new ItemAttribute();
public void findDescrPrice() {
/**
* Get the item name (description) for each list item
[code]...
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Apr 6, 2014
I am working on the Kevin Bacon - 6 degrees of bacon problem. I want to take my Array List and use the index and Values that I have saved in it as the Key and Value of a Hashmap. Below is my code.
HashMap<Integer, ArrayList<String>> actors =
new HashMap<Integer, ArrayList<String>>();
ArrayList array = new ArrayList();
try (BufferedReader br = new BufferedReader(
new FileReader("actors.txt"));)
[code]...
saving each one in it's own spot. I want to use the index of each one as the key to find it in the Hashmap....
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Apr 3, 2015
I'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
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Apr 2, 2015
I need assigning the selected hashmap values into a list and to display the values in a jsf page. The user will select certificates and will be stored in the below list:
private List<String> selectedCertificates = new ArrayList<String>();
The selectedCertificates will have the values ("AA","BB"). Now I will be passing the list into a hashmap in order to get the names and to display them on the jsf page.
My code is below:
Map<String, String> CertificatesNames =
new HashMap<String,String>(selectedCertificates.size());
CertificatesNames.put("AA", "Certificate A");
CertificatesNames.put("BB", "Certificate B");
CertificatesNames.put("CC", "Certificate C");
for(String key1: selectedCertificates) {
System.out.println(CertificatesNames.get(key1));
}
I want to display in my jsf page :
Certificate A
Certificate B
Now my issue is that is how to display all the values of the CertificatesNames.get(key1) in the jsf page as I tried to do the below and it printed all the values when I used the #{mybean.beans} using the :
List beans =
new ArrayList(CertificatesNames.values());
So how to do this?
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Feb 18, 2015
I am trying to write a program that will take any comma separated data set and return the values in an arraylist without any commas. Like if I input "hello, world, program, java" it would output an arraylist [hello,world,program,java].
public void run(){
String line = readLine("Enter a CSV-formatted line of data: ");
int lowerBound = 0;
String entry = new String("");
ArrayList<String> string = new ArrayList<String>();
[Code] .....
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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].....
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Feb 9, 2015
I 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]...
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Feb 28, 2014
I'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] ....
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Aug 29, 2014
I need a way to store the pixels values currently on the screen and compare them to the values on the first frame. Right now I'm using glreadpixels as follows:
currentBuffer= BufferTools.reserveByteData(mapSize);
glReadPixels(mapStartX, mapStartY, mapWidth, mapHeight, GL_BLUE, GL_UNSIGNED_BYTE, currentBuffer);
for (int i = 0; i < mapSize; i++) {
if (currentBuffer.get(i) != baseBuffer.get(i)) {
//Do nothing
continue;
}
//Do something
}
This works perfectly fine but turns out to be a real bottleneck, dropping the fps to a third of what it was. Is there any quicker way? All I'm after is speed, I don't even need to show it on the screen if the comparison is made "behind the scene".
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Feb 27, 2015
I have a question in mind that this is my registration form. I am sending these values from HTML form to server and database. I have question that in my case if I click next to Add Another Mobile no in HTML.then a block is genereated and each time a new name is generated.
My Question is if I click 6 times then 6 name attribute are generated. How can I send and differentiate them on my server side.
Because at their I will use something request.getAttribute("Attr_Name");
But they are same. How to do this?.
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Dec 7, 2014
I have GameConsole class with gamePlay(). There are two objects in this class that I want to access from a class in another package.
package blackjackControls;
public class GameConsole {
Player dealer; //both of these objects I am trying to bring over into the blackjackGUI package
Deck playingDeck;
public void gamePlay(){
[code].....
The dealer and playingDeck objects are giving me an error of unresolved. the way it is written I also get a static error on line 37. I know that I have not yet written in the actionEvent statement in the button constructor.
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Feb 18, 2015
I've created a method to calculate the ratio of one vowel to another, but I was hoping to get some feedback on another way I could approach the problem. The first bit of code is to find the vowels and assign them to an array ( for me, it seemed the easier thing to do in order to easily access the data). In the other bit of code, I have a method with two arguments (the vowels) to calculate the ratio.
public void findVowels(StringBuilder message, String delimiter) {
subString = message.toString().toLowerCase().split(delimiter);
vowelCounter = new int[5][subString.length];
// Remove all whitespace
for (int index = 0; index < subString.length; index++) {
subString[index] = subString[index].replaceAll("s", "");
[code]....
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