We wrote our square()
function like this:
func square(number: Int) -> Int {
return number * number
}
That names its parameter number
, so we can use number
inside the function to refer to it, but we must also use the name when running the function, like this:
let result = square(number: 8)
Swift lets us provide two names for each parameter: one to be used externally when calling the function, and one to be used internally inside the function. This is as simple as writing two names, separated by a space.
To demonstrate this, here’s a function that uses two names for its string parameter:
func sayHello(to name: String) {
print("Hello, \(name)!")
}
The parameter is called to name
, which means externally it’s called to
, but internally it’s called name
. This gives variables a sensible name inside the function, but means calling the function reads naturally:
sayHello(to: "Taylor")
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