CODEWITHSUNDEEP
javalistarraylist
pMpC
pMpC

Reputation: 257

Can't remove element from list because out of boundsexception

I have a List<Integer> nums = new ArrayList<>() and I do this:

for(int i=1;i<=9;i++)
    nums.add(i);

Here I have the list {1,2,3,4,5,6,7,8,9} .

What i want to do is given another List, if I receive the number 8, I want to remove the 8 from nums list. I'm doing that like this : shuffle.remove(genNumber-1);

The problem is If i already removed 3 numbers ({1,2,3} for instances) and the genNumber I receive is 9 it will try to remove at the index 9-1 = 8 which doesn't exist already because the current list is {4,5,6,7,8,9} <-> index=6, therefore didn't remove the number that i wanted that was the 9.

Thanks guys

Upvotes: 1

Views: 248

Answers (4)

user3480805
user3480805

Reputation: 31

nums.remove((Integer)9 ); should fix it; You could be passing an int into it, so it assumes you're calling the remove by index method remove(int index). By explicitly specifying 9 as an object you are using the remove(Object o) method of a list. References to documentation for list

Upvotes: 0

Mr Zorn
Mr Zorn

Reputation: 1913

Do not use an int, as that is going to remove whatever is at the index, not the matching object. You will need to use something of type Integer, which has a constructor that takes in an int and should be a quick fix.

int toRemove = 9;

nums.remove(new Integer(toRemove));

Upvotes: 1

Jay
Jay

Reputation: 2686

This question is strangely worded.
So the two solutions could be as followed.

  1. Remove by index
  2. remove by value.

1) If you want to remove by index then you are going to have to add some logic to how you generate your numbers to never exceed the list.size()

2) If you want to remove by value then you can just iterate through the list and remove the value you want to. Now you have to figure out what you want to do with that extra space in the array. (lets say you never deal with negative values you can add a "placeholder" of -1)

   for(int i = 0; i < list.size(); i++){
       if(list[i] == toMatchValue) list[i] = -1;
   }

Upvotes: 0

James
James

Reputation: 195

Pass in an Integer rather than an int. This will ensure that List#remove(Object) is used rather than List#remove(int).

Upvotes: 2

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