How to make different things happen when you collide with something in unity code example

Example: how to make colliders collide with some things but not other in unity

//ignores all collisions between the object collided with and the 
	//gameobject that this script is attached to

Physics.IgnoreCollision(
	collision.gameObject.GetComponent<SphereCollider>(), 
	gameObject.GetComponent<SphereCollider>());