So far, we learned different functions with some examples for each. Let's see if we can combine them to solve problems that we may encounter in our day-to-day application development.

Let's assume that we need to receive an object from a backend system as follows:

struct User {
    let name: String
    let age: Int
}

let users = [
    User(name: "Fehiman", age: 60),
    User(name: "Negar", age: 30),
    User(name: "Milo", age: 1),
    User(name: "Tamina", age: 6),
    User(name: "Neco", age: 30)
]

Then we need to calculate the total of ages in the users array. We can use a combination of the map and reduce functions to calculate totalAge as follows:

let totalAge = users.map { $0.age }.reduce(0) { $0 + $1 }

We were able to chain the map and reduce methods to achieve this.