IndexOutOfRangeException: Array index is out of range

Questions & Answers
1

I have a GameObject called walkways and it’s giving me an “Array index is out of range” error code despite the fact that I have the call maximum as “walkways.Length.”

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class spawnwalkway : MonoBehaviour {
	public GameObject[] walkways;
	public int plat_num_random;
	// Use this for initialization
	void Start () {
        StartCoroutine(spawnBlock());
	}
	
	// Update is called once per frame
	void Update () {
		
	}

    IEnumerator spawnBlock()
    {
		walkways = GameObject.FindGameObjectsWithTag("walkway");
        for (int z = 1; z < 100; z++)
		{
			Instantiate(walkways[Random.Range(0,walkways.Length)], new Vector3(-1.42637f, -0.4771186f, 2 * z + 8.574288f), Quaternion.identity);
            yield return new WaitForSeconds(0.5f);
        }

    }
}
2

@DatTardisDoh

I think that was the problem.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class spawnwalkway : MonoBehaviour
{
    public GameObject[] walkways;
    public int plat_num_random;
    // Use this for initialization
    void Start()
    {
        StartCoroutine(spawnBlock());
    }

    IEnumerator spawnBlock()
    {
        walkways = GameObject.FindGameObjectsWithTag("walkway");
        for (int z = 1; z < 100; z++)
        {
            //Changed from walkways[Random.Range(0, walkways.Length)]
            //to walkways[Random.Range(0, walkways.Length - 1)]
            Instantiate(walkways[Random.Range(0, walkways.Length - 1)], new Vector3(-1.42637f, -0.4771186f, 2 * z + 8.574288f), Quaternion.identity);
            yield return new WaitForSeconds(0.5f);
        }

    }
}
3

Even though you use walkways.Length when calling Random.Range, there is a case you haven’t handled: What if walkways does not contain any element? Then, Random.Range would return 0. However, walkways[0] does not exist since the array is empty.

So, make sure walkways has element before calling your function.

     walkways = GameObject.FindGameObjectsWithTag("walkway");
     if( walkways.Length > 0 )
     {
         for (int z = 1; z < 100; z++)
         {
             Instantiate(walkways[Random.Range(0, walkways.Length)], new Vector3(-1.42637f, -0.4771186f, 2 * z + 8.574288f), Quaternion.identity);
             yield return new WaitForSeconds(0.5f);
         }
     }
     else
         Debug.LogError("No walkway found! Are you sure the objects are correctly tagged?");