How to use map() with an optional value

Swift version: 5.1

Paul Hudson    @twostraws    May 28th 2019

The map() method of optionals allows you to transform the optional if it has a value, or do nothing if it is empty. This makes for shorter and more expressive code than doing a regular unwrap, and doesn’t require you to change your data type.

For example, if you had an optional string like this one:

let name: String? = "twostraws"

You could use the map() method to transform it safely, without having to check and unwrap it – if it were nil, the map() call would do nothing.

For example:

let twitterName = name.map { "@\($0)" }
print(twitterName)

That will print @twostraws.

Available from iOS – learn more in my book Pro Swift

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