Change sprite color on GameObjects from a list.

Hi, I’m trying to change the color on some sprites so they’re transparent.
I’m doing it with this code:

     public List<GameObject> redFloorList;

    for(int i = 0; i < redFloorList.Count; i++)
    {
        //Trying to change the color here
    	redFloorList*.collider.isTrigger = false;*

}
Does anyone know how to do this?

Try:

 redFloorList*.GetComponent<SpriteRenderer>().color = new Color(1.0f, 1.0f, 1.0f, 0.35f);*

Note that if any of the entries on the redFloorList are not sprites, this line will cause a null reference exception. If you want them to be completely transparent, then it would be better to disable the renderer:
redFloorList*.renderer.enabled = false;*