Three Random Objects From Array Without Repeat

Questions & Answers
1

I’m trying to get three different objects to instantiate randomly in three locations so that every time I start the game the objects spawn in different places. As of right now, I was able to figure out how to get the objects to spawn at each location without any objects overlapping each other. However, the problem I have now is that the same object spawns three times.

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

public class RandomItemsThree : MonoBehaviour {

    public GameObject[] slideSpots;
    public GameObject[] objects;
    GameObject randomObjects;
    GameObject firstObject;
    GameObject secondObject;
    GameObject thirdObject;

    int objectCount;
    int spawnCount;

    private void Start()
    {
        MyMethod();
    }

    void MyMethod ()
    {
        int spawn = Random.Range(0, slideSpots.Length);
        int stuff = Random.Range(0, objects.Length);

        randomObjects = objects[stuff];

        firstObject = GameObject.Instantiate(randomObjects, slideSpots[0].transform.position, Quaternion.identity);
        secondObject = GameObject.Instantiate(randomObjects, slideSpots[1].transform.position, Quaternion.identity);
        thirdObject = GameObject.Instantiate(randomObjects, slideSpots[2].transform.position, Quaternion.identity);
    }
}
2

You’re picking a random number with

         int stuff = Random.Range(0, objects.Length);

Then assigning randomObjects as the index of stuff into the objects array

randomObjects = objects[stuff];

But because you only generate stuff as a random number once and assign randomObjects once it will always be the same random number and therefore same object. You’ll need to have a copy of that code between each spawn for a new random number and object each time.

As a side note, if you do not want duplicates you can do a while loop for the random number generator checking against the last numbers, or copy the array and do a Fisher-Yates shuffle then pick the first three, or randomly pick from a list and remove spawns/objects when chosen. Make sure you check there are more than three items in the array for these approachs though.