Mathematical functions in Swift

Question

How do I use mathematical functions like sqrt    floor    round    sin    etc     When doing       floor 2 0      sqrt 2 0    I get      error  use of unresolved identifier  floor    error  use of unresolved identifier  sqrt

User · Answer

You can use them right inline   var square   9 4 var floored   floor square  var root   sqrt floored   println  Starting with   square   we rounded down to   floored   then took the square root to end up with   root

User · Answer

To use the math-functions you have to import Cocoa  You can see the other defined mathematical functions in the following way  Make a Cmd-Click on the function name sqrt and you enter the file with all other global math functions and constanst   A small snippet of the file      func pow    CDouble     CDouble  - gt  CDouble  func sqrtf    CFloat  - gt  CFloat func sqrt    CDouble  - gt  CDouble  func erff    CFloat  - gt  CFloat     var M LN10  CDouble   get      loge 10           var M PI  CDouble   get      pi                var M PI 2  CDouble   get      pi 2              var M SQRT2  CDouble   get      sqrt 2

User · Answer

For the Swift way of doing things  you can try and make use of the tools available in the Swift Standard Library  These should work on any platform that is able to run Swift   Instead of floor    round   and the rest of the rounding routines you can use rounded       let x   6 5     Equivalent to the C  round  function  print x rounded  toNearestOrAwayFromZero      Prints  7 0      Equivalent to the C  trunc  function  print x rounded  towardZero      Prints  6 0      Equivalent to the C  ceil  function  print x rounded  up      Prints  7 0      Equivalent to the C  floor  function  print x rounded  down      Prints  6 0    These are currently available on Float and Double and it should be easy enough to convert to a CGFloat for example   Instead of sqrt   there s the squareRoot   method on the FloatingPoint protocol  Again  both Float and Double conform to the FloatingPoint protocol   let x   4 0 let y   x squareRoot     For the trigonometric functions  the standard library can t help  so you re best off importing Darwin on the Apple platforms or Glibc on Linux  Fingers-crossed they ll be a neater way in the future    if os OSX     os iOS  import Darwin  elseif os Linux  import Glibc  endif  let x   1 571 print sin x      Prints   1 0

User · Answer

To be perfectly precise  Darwin is enough  No need to import the whole Cocoa framework   import Darwin   Of course  if you need elements from Cocoa or Foundation or other higher level frameworks  you can import them instead

User · Answer

For people using swift  2 2  on Linux i e  Ubuntu  the import is different   The correct way to do this is to use Glibc  This is because on OS X and iOS  the basic Unix-like API s are in Darwin but in linux  these are located in Glibc  Importing Foundation won t help you here because it doesn t make the distinction by itself  To do this  you have to explicitly import it yourself    if os macOS     os iOS  import Darwin  elseif os Linux     CYGWIN import Glibc  endif   You can follow the development of the Foundation framework here to learn more    EDIT  December 26th  2018  As pointed out by  C  ur  starting from swift 3 0 some math functions are now part of the types themselves  For example  Double now has a squareRoot function  Similarly  ceil  floor  round  can all be achieved with Double rounded FloatingPointRoundingRule  - gt  Double   Furthermore  I just downloaded and installed the latest stable version of swift on Ubuntu 18 04  and it looks like Foundation framework is all you need to import to have access to the math functions now  I tried finding documentation for this  but nothing came up     swift           Welcome to Swift version 4 2 1  swift-4 2 1-RELEASE   Type  help for assistance    1 gt  sqrt 9  error  repl swift 1 1  error  use of unresolved identifier  sqrt  sqrt 9           1 gt  import Foundation   2 gt  sqrt 9   R0  Double   3   3 gt  floor 9 3   R1  Double   9   4 gt  ceil 9 3    R2  Double   10

User · Answer

As other noted you have several options  If you want only mathematical functions  You can import only Darwin   import Darwin   If you want mathematical functions and other standard classes and functions  You can import Foundation   import Foundation   If you want everything and also classes for user interface  it depends if your playground is for OS X or iOS   For OS X  you need import Cocoa   import Cocoa   For iOS  you need import UIKit   import UIKit   You can easily discover your playground platform by opening File Inspector    1

[swift] Mathematical functions in Swift

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