If you like a challenge, then I suggest that you try the following: Try to get any pineapple juice in Lausanne, on a Saturday, after 18h00.

You might think: Oh, just try a petrol station.
No luck there, buddy. If you’re lucky they might just about have apple juice.

So, next stop the Aperto 24 in the train station. Surely they will have it, right?
Close, but no cigar, let alone pineapple juice. But if you want to buy wine or salad instead, then this is your place.

Ah, but what about the Coop Pronto? They even have different kinds of fresh bread, so they certainly should have pineapple juice.
Well, you can get your orange juice in three different size, from two different brands and from three different shelves, you can also get Kiwi-Apple juice or other multi-fruit juices containing traces of pineapple, but no pineapple juice itself.

The moral of the story:
If you plan to make cocktails (such as Piña Colada) with proper pineapple juice, then I suggest that you actually “plan” this more than 3 hours in advance.