How to use map() with an optional value

Paul Hudson    February 12th 2018    @twostraws

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

Did this solution work for you? Please pass it on!

Tweet

Other people are reading…

• What is a nib?
• When to use a set rather than an array
• What are implicitly unwrapped optionals?
• Why is immutability important?
• How to convert Data to a String

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.