Swift’s Nil Coalescing Operator AKA the “?? Operator” or “Double Question Mark Operator”

This last week I was introduced to quite a funky little operator in Swift called the Nil Coalescing operator. It is basically a shorthand for the ternary conditional operator when used to test for nil.

For example traditionally in many programming languages you could do something like this to check for nil/null…

stringVar != nil ? stringVar! : "a default string"

Here if the condition is not nil the value of stringVar will be returned otherwise the value “a default string” is returned.

This can be shortened in Swift by using the Nil Coalescing operator.

stringVar ?? "a default string"

This does exactly the same thing, if stringVar is not nil then it is returned, however if it is nil the value “a default string” is returned.

Love it.

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Long time no posts.

Woah just realised it’s been 4 years since I last did a techie post, and 2 since the last non-techie one.  I hope to start writing more regular posts again.

Well since 2010 I’ve been learning iOS development and so the blog will probably focus a bit more on that from now on.