swift - How to prevent a 'Array index out of range' error? -

is there way, similar using if let and/or optionals, test whether index empty buffer in swift?

define own:

extension array {   func ref (i:int) -> t? {     return 0 <= && < count ? self[i] : nil   } } 

the ref() function returns optional, can nil, , can use if let syntax access returned value ref() when exists. use such:

var mya = [10,20,30] if let val = mya.ref(index) {   // use 'val' if index < 3 } else {   // if index high }