Swift - Making integers positive

Using the usual abs() function handles this nicely:

  let sample = -7
  print(abs(sample))
  // 7

In Swift 5, either of the following two approaches lets you turn an integer into its absolute value.

#1. Obtain an Int's absolute value through its magnitude property

The Int type provides magnitude (https://developer.apple.com/documentation/swift/int/2886869-magnitude). This property is declared like this:

  var magnitude: UInt { get }

For a numeric input x, the value x.magnitude gives x's absolute value.

Here is an example using the magnitude property to retrieve the absolute value from an instance of Int:

  let input = -4
  print(input.magnitude) // prints: 4

#2. Obtain an Int's absolute value through the abs(_:) method

A global numeric function in Swift is named abs(_:) (https://developer.apple.com/documentation/swift/2885649-abs). Its method declaration is:

  func abs<T>(_ x: T) -> T where T : Comparable, T : SignedNumeric

Gives the supplied number's absolute value.

Here is an example calling the global abs(_:) function to retrieve the absolute value from an instance of Int:

  let input = -4
  print(abs(input)) // prints: 4

For the absolute value of either a double or an Int, call the fabs function:

  var sample = -14.28
  print(fabs(sample)) // 14.28
  sample = -9
  print(fabs(sample)) // 9

To make a number positive or leave it positive.

You can do this:

  abs() for int
  fabs() for double
  fabsf() for float