Originally Posted by
Rob Phillips Welcome to iMore! Your Snapchat friends should have nothing to do with your removing and then reinstalling the app. They’re tied to your account so as long as you use the same username and password as before you should be fine. If you’re 100% sure that you’re signed in correctly and your friends have somehow disappeared (which I’ve never heard of before) then your only choice is to add them back manually.
This. Make sure you're using the same login credentials and everything should resolve itself.