NullReferenceException: Object reference not set to an instance of an object

Hi, apologies in advance, I know I'm making some basic error here, but...

I'm trying to instantiate and destroy gameobjects referenced in an array.

It works fine when I do it with a single reference like this...

Code (CSharp):

1.    public void NextButton()
2.     {
3.         Destroy(instance);
4.         instance = Instantiate(prefabs[whichPrefab], parentTransforms[1]);
5.     }

So I expected it to be simple to do the same with an array like this

Code (CSharp):

1.    public void NextButton()
2.     {
3.         for (int i = 0; i < parentTransforms.Length; i++)
4.         {
5.             Destroy(instances[i]);
6.             instances[i] = Instantiate(prefabs[whichPrefab], parentTransforms[i]);
7.         }
8.     }

But this give a "NullReferenceException: Object reference not set to an instance of an object"

Can anyone explain what I'm misunderstanding please?
Thanks in advance

 

Did you try this...

Code (CSharp):

1.     public void NextButton()
2.     {
3.         for (int i = 0; i < parentTransforms.Length; i++)
4.         {
5.             if (instances[i] == null) continue;
6.             Destroy(instances[i]);
7.             instances[i] = Instantiate(prefabs[whichPrefab], parentTransforms[i]);
8.         }
9.     }