Add Multidimensinal array to an array list using Java

Question

I am having a method(function) that is supposed to add a (8*6)Array to an Array list. Function is called several times.

int [][] KeySelection = new int [8][7];

  for(int i=0;i<KeySelection.length;i++){
  for(int j=0;j<KeySelection[0].length;j++){
      KeySelection[i][j] = (int) (Math.random () * 2);

     }
  }

Each time this function is called a totally new KeySelection Array is done. What i need now is to declare an array list so that it could store all the KeySelection Arrays in that list.

So that when i need the first KeySelection Table i could find it in the first index of the Array list. Could somebody Help

Rohit Jain · Accepted Answer · 2012-11-17 12:29:39Z

2

Create an ArrayList of type int[][]: -

List<int[][]> list = new ArrayList<int[][]>();

And then, add your array to this list after creation: -

list.add(keySelection);

NOTE: - Variable name should start with lowercase letters.

answered Nov 17, 2012 at 12:29

Rohit Jain

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7 Comments

user1111726 Over a year ago

OK perfect.. now Assume the list is full, when I need to call ,Lets say the first KeySelection Table,, what is the exact syntax

JB Nizet Over a year ago

int[][] firstMatrix = list.get(0); Read the Java tutorial on collections and the List javadoc

user1111726 Over a year ago

One More question..Does the "(Math.random () * 2)" add the exact same values to the exact same locations.. so if the function runs twice to i get same KeySelection Tables

Rohit Jain Over a year ago

@user1111726.. What do you exactly want to add in those arrays?

user1111726 Over a year ago

I dont think I really get u there.. but what i am asking.. is that normal to have the two tables identical.. because thats what i wasnt and thats what is happening.. or is it just a conicedence

|

Juvanis · Accepted Answer · 2012-11-17 12:29:44Z

1

Since arrays in Java are special type of objects, you can use an ArrayList of objects to hold your arrays. Declare your list like that and populate it via for loop etc.

ArrayList<int[][]> list = new ArrayList<int[][]>();

edited Nov 17, 2012 at 12:29

answered Nov 17, 2012 at 12:16

Juvanis

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4 Comments

Juvanis Over a year ago

@user1111726 if you don't have such a class, so how your code uses this class ???

JB Nizet Over a year ago

The code doesn't use a KeySelection class, but a variable named KeySelection.

user1111726 Over a year ago

I edited the question for better understanding.. the method intializes a new 2-D array called "KeySelection" every time the function is called, new values in the KeySelection table.. What i need is to add them to an array list each time the function is called so at the end I could have a list contating all Arrays of KeySelection

user1111726 Over a year ago

@JB Nizet.. Yes u got me.. is there a way to add those KeySelection Varaiable to the Arraylist each time the function is called

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