How to check object is nil or not in swift?

Question

Suppose I have String like :

var abc : NSString = \"ABC\"

and I want to check that it is nil or not and for that I try :

if         


        

Answer 1

The case of if abc == nil is used when you are declaring a var and want to force unwrap and then check for null. Here you know this can be nil and you can check if != nil use the NSString functions from foundation.

In case of String? you are not aware what is wrapped at runtime and hence you have to use if-let and perform the check.

You were doing following but without "!". Hope this clears it.

From apple docs look at this:

let assumedString: String! = "An implicitly unwrapped optional string."

You can still treat an implicitly unwrapped optional like a normal optional, to check if it contains a value:

if assumedString != nil {
    println(assumedString)
}
// prints "An implicitly unwrapped optional string."