Map function is quite a convenience method that often used in functional(mainly) programming.
In Swift, all collection types(Array,Dictionary,Set...) support map. It take a closure that take element type from T and output type U then transform from [T] to [U].

In most case, you will see :
in short hand:
How convenience is that to old NSArray.
In real world case, things are more complicating.
Let's say you have a type A, which can init from another type B.
Now you have an array of [B], you would like to transform it to another array [A]. How would you do?
Typically, you may use the following code:
Solid?
Actually you make it better :
Sweet.

If you want to make it look more functional, you can declare a operator for example <<< in this case.
Then you can:
Clean and clear.
There are still many other small but interesting skills in Swift that can help us code in a better way.
We will only observe them if we can free our mind from Objective-C age.

 

Original post from my previous site: http://povoq.blogspot.com/2017/04/blog-post.html

and the original post is originally from my linked.in account...