When writing code, less is more. Programmers often try to keep their code as concise as possible to make their programs readable and efficient.

Using type inference, the compiler can automatically determine the data type of a Swift expression. We can use type inference to declare dictionaries with less code.

When we first learned how to declare a dictionary, our code looked like this:

var fruitStand: [String: Int] = [
  "Apples": 12,
  "Bananas": 20
]

With type inference, we can initialize fruitStand with this syntax:

var fruitStand = [
  "Apples": 12,
  "Bananas": 20
]

We eliminated the type annotation [String: Int] from the initialization.

With type inference, the compiler deduces that the keys are type String and the values are type Int.

To learn more about type inference, check out Swift’s Language Guide.