How to forward functions with variadic parameters?

by

This has nothing to do with tuples. Anyway, it isn’t possible to convert from an array to a tuple in the general case, as the arrays can have any length, and the arity of a tuple must be known at compile time.

However, you can solve your problem by providing overloads:

// This function does the actual work
func sumOf(_ numbers: [Int]) -> Int {
    return numbers.reduce(0, +) // functional style with reduce
}

// This overload allows the variadic notation and
// forwards its args to the function above
func sumOf(_ numbers: Int...) -> Int {
    return sumOf(numbers)
}

sumOf(2, 5, 1)

func averageOf(_ numbers: Int...) -> Int {
    // This calls the first function directly
    return sumOf(numbers) / numbers.count
}

averageOf(2, 5, 1)

Maybe there is a better way (e.g., Scala uses a special type ascription to avoid needing the overload; you could write in Scala sumOf(numbers: _*) from within averageOf without defining two functions), but I haven’t found it in the docs.

More Related Contents:

  1. how to check if there is any string from index 0 to 5 in an array of type Any [closed]
  2. remove an index number from array
  3. How to check if an element is in an array
  4. How to sort an array of custom objects by property value in Swift
  5. How to find index of list item in Swift?
  6. Swift: Creating an Array with a Default Value of distinct object instances
  7. Two-dimensional array in Swift
  8. How do I insert an element at the correct position into a sorted array in Swift?
  9. Making my function calculate average of array Swift
  10. Converting a C char array to a String
  11. Shorthand to test if an object exists in an array for Swift?
  12. How to get list of common elements of 2 array in Swift?
  13. Swift sort an array with strings and numbers [duplicate]
  14. Flatten [Any] Array Swift
  15. How to remove an element from an array in Swift
  16. Is it possible to make an Array extension in Swift that is restricted to one class?
  17. Cannot convert value of type ‘Meme!’ to expected argument type ‘@noescape (Meme) throws -> Bool’
  18. How to pass Scala array into Scala vararg method?
  19. Swift 3 2d array of Int
  20. Find Duplicate Elements In Array Using Swift
  21. How can I interleave two arrays?
  22. Swift: What’s the best way to pair up elements of an Array
  23. Swift 4 JSON Codable – value returned is sometimes an object, others an array
  24. swift: modifying arrays inside dictionaries
  25. How can I convert an array to a tuple?
  26. How to stable sort an array in swift?
  27. How to return first 5 objects of Array in Swift?
  28. What does $0 and $1 mean in Swift Closures?
  29. How can I run through three separate arrays in the same for loop?
  30. Swift: Binary search for standard array?

Leave a Comment