Object.operator !=

Description

Compares if two objects refer to a different object.

    var target : Transform;
    function Update () {
        // the target object does not refer to the same object as our transform
        if (target != transform) {
            print("Another object");
        }
    }

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public Transform target;
    void Update() {
        if (target != transform)
            print("Another object");
        
    }
}