Unwrapping optionals

Optional strings might contain a string like “Hello” or they might be nil – nothing at all.

Consider this optional string:

var name: String? = nil

What happens if we use name.count? A real string has a count property that stores how many letters it has, but this is nil – it’s empty memory, not a string, so it doesn’t have a count.

Because of this, trying to read name.count is unsafe and Swift won’t allow it. Instead, we must look inside the optional and see what’s there – a process known as unwrapping.

A common way of unwrapping optionals is with if let syntax, which unwraps with a condition. If there was a value inside the optional then you can use it, but if there wasn’t the condition fails.

For example:

if let unwrapped = name {
    print("\(unwrapped.count) letters")
} else {
    print("Missing name.")
}

If name holds a string, it will be put inside unwrapped as a regular String and we can read its count property inside the condition. Alternatively, if name is empty, the else code will be run.

SPONSORED From August 2nd to 8th you can join a FREE crash course for mid/senior iOS devs who want to achieve an expert level of technical and practical skills – it’s the fast track to being a complete senior developer!

Save your spot now

Sponsor Hacking with Swift and reach the world's largest Swift community!