Float by Example - Swift Programming Language

Overview

  • Floating-point numbers are numbers with a fractional component, such as 3.14159, 0.1, and -273.15.
  • Float represents a 32-bit floating-point number.

1. Converting Floating-Point Values

1.1 init(_:)

  • Creates a new instance that approximates the given value.
let x: Double = 21.25
let y = Float(x)
print(y)
//prints 21.25

1.2 init(signOf:magnitudeOf:)

  • Creates a new floating-point value using the sign of one value and the magnitude of another.
let a = -21.5
let b = 305.15
let c = Double(signOf: a, magnitudeOf: b)
print(c)
//prints -305.15

1.3 init(sign:exponent:significand:)

  • Creates a new value from the given sign, exponent, and significand.
let z = Double(sign: .plus, exponent: -2, significand: 1.5)
print(z)
//prints 0.375

2. Performing Calculations

2.1 Floating-Point Operators for Float

  • Perform arithmetic and bitwise operations or compare values.
print(a + b)
//prints 283.65

print(a - b)
//prints -326.65

print(a * b)
//prints -6560.725

print(a / b)
//prints -0.0704571522202196

a += b
print(a)
//prints 283.65

a -= b
print(a)
//prints -21.5

a *= b
print(a)
//prints -6560.725

a /= b
print(a)
//prints -21.5

2.2 squareRoot()

  • Returns the square root of the value, rounded to a representable value.
func hypotenuse(_ a: Double, _ b: Double) -> Double {
    return (a * a + b * b).squareRoot()
}

let (dx, dy) = (3.0, 4.0)
let distance = hypotenuse(dx, dy)
print(distance)
//prints 5.0

2.3 remainder(dividingBy:)

  • Returns the remainder of this value divided by the given value.
let q = (x / 0.75).rounded(.toNearestOrEven)
let r = x.remainder(dividingBy: 0.75)
print(q,r)
// prints 28.0 0.25

2.4 negate()

  • Replaces this value with its additive inverse.
var k = 21
k.negate()
print(k)
//prints -21

3. Rounding

3.1 rounded()

  • Returns this value rounded to an integral value using “schoolbook rounding.”
let m = 6.5
print(m.rounded(.toNearestOrAwayFromZero))
// prints 7.0
print(m.rounded(.towardZero))
//prints 6.0
print(m.rounded(.up))
//prints 7.0
print(m.rounded(.down))
//prints 6.0

3.2 round()

  • Rounds this value to an integral value using “schoolbook rounding.”
var j = 5.2
j.round()
print(j)
// prints 5.0
var h = 5.5
h.round()
print(h)
//prints 6.0
var g = -5.5
g.round()
print(g)
//prints -5.0

4. Comparing Floats

4.1 comparison

print(a > b)
//prints false

print(a < b)
//prints true

print(a <= b)
//prints true 

print(a >= b)
//prints false 

print(a == b)
//prints false

4.2 maximum(::)

Returns the greater of the two given values.

print(Double.maximum(10.0, -25.0))
//prints 10

4.3 minimum(::)

  • Returns the lesser of the two given values.
print(Double.minimum(10.0, -25.0))
//prints -25.0

5. Finding the Sign and Magnitude

5.1 magnitude

  • The magnitude of this value.
let num1 = -259.0001
print(num1.magnitude)
//prints 259.0001

5.2 sign

  • The sign of the floating-point value.
let num1 = -259.0001
print(num1.sign)
//prints minus

6. Querying a Float

6.1 ulp

  • The unit in the last place of this value.
let num2 = 0.23
print(num2.ulp)
//prints 2.77555756156289e-17

6.2 significand

  • The significand of the floating-point value.
let num3 = 9.91
print(num3.significand)
//prints 1.23875

6.3 exponent

  • The exponent of the floating-point value.
let num3 = 9.91
print(num3.exponent)
//prints 3

6.4 nextUp

  • The least representable value that compares greater than this value.
let num4 = 10.0
print(num4.nextUp)
//prints 10.0

6.5 nextDown

  • The greatest representable value that compares less than this value.
let num4 = 10.0
print(num4.nextDown)
//prints 10.0

6.6 binade

  • The floating-point value with the same sign and exponent as this value, but with a significand of 1.0.
print(num4.binade)
//prints 8.0

7. Accessing Numeric Constants

7.1 pi

  • The mathematical constant pi.
print(Double.pi)
//prints 3.14159265358979

7.2 infinity

  • Positive infinity.
let x1 = Double.greatestFiniteMagnitude
let y1 = x1 * 2
print(y1)
//prints inf

7.3 greatestFiniteMagnitude

  • The greatest finite number representable by this type.
let x1 = Double.greatestFiniteMagnitude
print(x1)
//prints 1.79769313486232e+308

7.4 nan

  • A quiet NaN (“not a number”).
let x1 = Double.greatestFiniteMagnitude
print(x1 > Double.nan)
//prints false

7.5 signalingNaN

  • A signaling NaN (“not a number”).
let x1 = Double.greatestFiniteMagnitude
print(x1 > Double.signalingNaN)
//prints false

7.6 ulpOfOne

  • The unit in the last place of 1.0.
let x1 = Double.greatestFiniteMagnitude
print(x1 > Double.ulpOfOne)
//prints true

7.7 leastNormalMagnitude

  • The least positive normal number.
let x1 = Double.greatestFiniteMagnitude
print (x1 < Double.leastNormalMagnitude)
//prints false

7.8 leastNonzeroMagnitude

  • The least positive number.
let x1 = Double.greatestFiniteMagnitude
print (x1 < Double.leastNonzeroMagnitude)
//prints 4.94065645841247e-324

8. Working with Binary Representation

8.1 bitPattern

  • The bit pattern of the value’s encoding.
let num5 = 3000.00000
print(num5.bitPattern)
//prints 4658815484840378368

8.2 significandBitPattern

  • The raw encoding of the value’s significand field.
let num5 = 3000.00000
print(num5.significandBitPattern)
//prints 2093470139285504

8.3 exponentBitPattern

  • The raw encoding of the value’s exponent field.
let num5 = 3000.00000
print(num5.exponentBitPattern)
//prints 1034

8.4 significandWidth

  • The number of bits required to represent the value’s significand.
let num5 = 3000.00000
print(num5.significandWidth)
//prints 8

9. Querying a Float's State

9.1 isZero

  • A Boolean value indicating whether the instance is equal to zero.
let num5 = 3000.00000
print(num5.isZero)
//prints false

9.2 isSubnormal

  • A Boolean value indicating whether the instance is subnormal.
let num5 = 3000.00000
print(num5.isSubnormal)
//prints false

10. Describing a Float

10.1 description

  • A textual representation of the value.
let num5 = 3000.00000
print(num5.description)
//prints 3000.0

10.2 debugDescription

  • A textual representation of the value, suitable for debugging.
let num5 = 3000.00000
print(num5.debugDescription)
//prints 3000.0

10.3 customMirror

  • A mirror that reflects the Float instance.
let num5 = 3000.00000
print(num5.customMirror)
//prints Mirror for Double

10.4 hashValue

  • The number’s hash value.
print(num5.hashValue)
//prints 4658815484840378368

Next - Double by Example


You can download the swift playground of all above examples from Here



Discussion

Read Community Guidelines
You've successfully subscribed to Developer Insider
Great! Next, complete checkout for full access to Developer Insider
Welcome back! You've successfully signed in
Success! Your account is fully activated, you now have access to all content.