How to make a variadic function
Swift version: 5.2
Variadic functions are functions that accept any number of parameters. The most common one in Swift is print() – most people use it to print a single value, but you can actually pass as many as you want, like this:
print(1, 2, 3, 4, 5)To make a variadic function of your own, just add ... after any parameter. For example, we could write a sum() function that accepts any number of integers and adds them together, like this:
func sum1(_ numbers: Int...) -> Int {
var total = 0
for number in numbers {
total += number
}
return total
}Or if you wanted to write that functionally, you would use reduce():
func sum2(_ numbers: Int...) -> Int {
return numbers.reduce(0, +)
}Notice how we specify Int... rather than Int – that means this function can be called using no integers, one integer, or even a hundred integers, and Swift will automatically convert them to be an array of integers inside the function.
So, it would be called like this:
let total = sum2(1, 2, 3, 4, 5)
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