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Paula Samuels
1,853 PointsWhat in the world does "unwrapping an optional" mean?
I've watched the "Swift Functions & Optionals" video twice, but I still don't understand this term.
1 Answer
Michael Hulet
47,912 PointsAn optional is a variable that could either contain a value or nil. In order to find out which one it is, you need to "unwrap" it. This is done in one of 2 ways. You could either unwrap it implicitly (also known as "if let" syntax), like this:
//This variable could either contain a String or nil. In this case, it will contain the string "Hello"
var optional: String? = "Hello"
//Because it could be nil, we have to check if it is before we can use it
if let validString = optional{
println(validString)
}
If you need to perform a quick operation and know the value won't be nil, you could explicitly unwrap it (using an exclamation point), like this:
//This is an optional, same as before
var optional: String? = "Hello"
//We're lazy and wanna save a couple lines, and we know it's not nil, so we can explicitly unwrap the optional variable
println(optional!)