We can use different built-in properties to help us understand information about specific collection types, like sets or arrays, in our programs!

For example, we can use .count to find out how many elements are contained within a set:

setName.count

We learned about using .count with arrays. .count returns an Int value that represents the number of values stored inside of a specified set.

For example, we can create a set to store the items we found in our lunchbox:

var lunchbox: Set = ["Apple", "Sandwich"]

Then, we could use .count to find out how many items we have in lunchbox:

print("I have \(lunchbox.count) items in my lunchbox!")

// Prints: I have 2 items in my lunchbox!

If we want to find out if our set is empty, we can use the .isEmpty property to check if there are values contained within our set.

setName.isEmpty

• If there are no values in the set, the expression will return true.
• If there are values, the expression will return false.

Let’s revisit the set instruments and place instruments.isEmpty in the conditional of an if statement:

var instruments = Set<String>()

if instruments.isEmpty {
  print("Let's sign up for piano lessons!")
}
// Prints: Let's sign up for piano lessons!