ios - Using if statements in Swift? -

whats best way execute code if optional isn't nil? clearly, obvious way directly check if value nil:

if optionalvalue != nil {      //execute code } 

i've seen following:

if let _ = optionalvalue {     //execute code } 

the second 1 seems more in line swift since it's using optional chaining. there advantages using 1 method on other? there better way it? better mean "more in line swift", whatever means.

optional binding should used if need unwrapped value. shortcut longer expression, , think should thought in terms. in fact, in swift 1.2 optional binding expression:

if let unwrapped = optional {     println("use unwrapped value \(unwrapped)") } 

is syntactic sugar code (remember optionals are, under hood, instances of optional<t> enumeration):

switch optional { case .some(let unwrapped):     println("use unwrapped value \(unwrapped)") case .none:     break } 

using optional binding , not assigning unwrapped value variable having box may contain tv inside. don't remove tv box if purpose verify whether box empty or not - open box , inside.

so, if need execute code if variable not nil, don't need nor use actual value contained in optional variable, not-nil check is, in opinion, best way it.