I am going to make a coconut/pineapple cake. It calls for 1 cup water or milk. Can I substitute pineapple juice instead?

I've used pineapple juice in place of my water in my pineapple upside down cake and it turned out awesome!!!

Don't see why you couldn't. I have used fruit juices before in place of the water and have had no trouble. Gives the cake a better flavor as well.

just curious about this would you have to watch the sugar content of the juice that you would be using instead of milk or water?