First off, Zurich is a village compared to London but it does have a busy night life, loads of clubs and bars. Going out will be more expensive than London but it is much safer.
It's difficult to make close friends with the locals unless you have been here and known them for a few years but personally, I have more friends now than I ever had in the UK. There's a great FB group for people younger than me wanting to socialise in Zurich called Zurich People Alive
and it's very busy with both day and night events. I suggest you join that and post an intro.