How can I convert from degrees to radians?

Question

I am trying to convert this Obj-C code to Swift code but I don't know what the equivalent of this code should be ?

#define DEGREES_TO_RADIANS(degrees)((M_PI * degrees)/180) 

I googled and found this

But I don't understand how to convert that in Swift in my case?

Answer 1

Xcode 11 • Swift 5.1 or later

extension BinaryInteger {     var degreesToRadians: CGFloat { CGFloat(self) * .pi / 180 } }  extension FloatingPoint {     var degreesToRadians: Self { self * .pi / 180 }     var radiansToDegrees: Self { self * 180 / .pi } } 

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Playground

45.degreesToRadians         // 0.7853981633974483  Int(45).degreesToRadians    // 0.7853981633974483 Int8(45).degreesToRadians   // 0.7853981633974483 Int16(45).degreesToRadians  // 0.7853981633974483 Int32(45).degreesToRadians  // 0.7853981633974483 Int64(45).degreesToRadians  // 0.7853981633974483  UInt(45).degreesToRadians   // 0.7853981633974483 UInt8(45).degreesToRadians  // 0.7853981633974483 UInt16(45).degreesToRadians // 0.7853981633974483 UInt32(45).degreesToRadians // 0.7853981633974483 UInt64(45).degreesToRadians // 0.7853981633974483  Double(45).degreesToRadians    // 0.7853981633974483 CGFloat(45).degreesToRadians   // 0.7853981633974483 Float(45).degreesToRadians     // 0.7853981 Float80(45).degreesToRadians   // 0.78539816339744830963 

If you would like to make the binary integer return a floating point type instead of always returning a CGFloat you can make a generic method instead of a computed property:

extension BinaryInteger {     func degreesToRadians<F: FloatingPoint>() -> F {  F(self) * .pi / 180 } } 

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let radiansDouble: Double = 45.degreesToRadians()   // 0.7853981633974483 let radiansCGFloat: CGFloat = 45.degreesToRadians() // 0.7853981633974483 let radiansFloat: Float = 45.degreesToRadians()     // 0.7853981 let radiansFloat80: Float80 = 45.degreesToRadians() // 0.78539816339744830963 

Answer 2

This is not identically what you asked, but in Swift 3 / iOS 10, you can use the Measurement type and do the conversion without knowing the formula!

let result = Measurement(value: 45, unit: UnitAngle.degrees)     .converted(to: .radians).value