[docs] Extensions.md: Numbers & Geometry section
This commit is contained in:
Daniel Arantes Loverde
@@ -1118,7 +1118,274 @@ false.string // "false"
|
||||
|
||||
## Numbers & Geometry
|
||||
|
||||
<!-- batch 5 -->
|
||||
<details>
|
||||
<summary><b>Int</b> — conversions, digits, primes, roman numerals, operators</summary>
|
||||
|
||||
### `var double: Double` / `var float: Float` / `var cgFloat: CGFloat` / `var uInt: UInt` / `var uInt32: UInt32` / `var uInt64: UInt64`
|
||||
Straight numeric conversions (`uInt32`/`uInt64` truncate).
|
||||
|
||||
```swift
|
||||
5.double // 5.0
|
||||
(-1).uInt32 // 4294967295
|
||||
```
|
||||
|
||||
### `var countableRange: CountableRange<Int>`
|
||||
`0..<self`.
|
||||
|
||||
```swift
|
||||
3.countableRange // 0..<3
|
||||
```
|
||||
|
||||
### `var degreesToRadians: Double` / `var radiansToDegrees: Double`
|
||||
Angle conversion.
|
||||
|
||||
```swift
|
||||
180.degreesToRadians // 3.14159…
|
||||
```
|
||||
|
||||
### `var digits: [Int]` / `var digitsCount: Int`
|
||||
Decimal digits of `abs(self)`, and how many.
|
||||
|
||||
```swift
|
||||
1234.digits // [1, 2, 3, 4]
|
||||
1234.digitsCount // 4
|
||||
```
|
||||
|
||||
### `var kFormatted: String`
|
||||
Compact "k"/"kk" formatting for values ≥ 1000.
|
||||
|
||||
```swift
|
||||
5300.kFormatted // "5k"
|
||||
2_500_000.kFormatted // "25kk"
|
||||
```
|
||||
|
||||
### `var timestampToDate: Date`
|
||||
`Date(timeIntervalSince1970:)`.
|
||||
|
||||
```swift
|
||||
1_700_000_000.timestampToDate // 2023-11-14 …
|
||||
```
|
||||
|
||||
### `var satsToBTC: String` / `var convertToBTC: String` / `var toBTC: String`
|
||||
Satoshis → BTC string, 8 decimal places. All three are the same.
|
||||
|
||||
```swift
|
||||
150_000_000.satsToBTC // "1.50000000"
|
||||
```
|
||||
|
||||
### `func isPrime() -> Bool`
|
||||
Primality test (trial division up to √n).
|
||||
|
||||
```swift
|
||||
7.isPrime() // true
|
||||
9.isPrime() // false
|
||||
```
|
||||
|
||||
### `func romanNumeral() -> String?`
|
||||
Roman numerals for positive integers, `nil` for 0 or negative.
|
||||
|
||||
```swift
|
||||
2024.romanNumeral() // "MMXXIV"
|
||||
```
|
||||
|
||||
### `func roundToNearest(_ number: Int) -> Int`
|
||||
Round to the closest multiple of `number`.
|
||||
|
||||
```swift
|
||||
47.roundToNearest(10) // 50
|
||||
```
|
||||
|
||||
### Operators
|
||||
| Operator | Meaning | Example |
|
||||
|---|---|---|
|
||||
| `a ** b` | exponentiation → `Double` | `2 ** 3` → `8.0` |
|
||||
| `√ n` (prefix) | square root → `Double` | `√ 9` → `3.0` |
|
||||
| `a ± b` (infix) | `(a+b, a-b)` | `5 ± 3` → `(8, 2)` |
|
||||
| `± n` (prefix) | `(n, -n)` | `± 2` → `(2, -2)` |
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>Float / Double</b></summary>
|
||||
|
||||
### `var int: Int` / `var double: Double` (Float) / `var float: Float` (Double) / `var cgFloat: CGFloat`
|
||||
Numeric conversions.
|
||||
|
||||
### `var satsToBTC / convertToBTC / toBTC`
|
||||
Satoshis → BTC (`Double` here, unlike `Int` which returns a `String`).
|
||||
|
||||
```swift
|
||||
150_000_000.0.satsToBTC // 1.5
|
||||
```
|
||||
|
||||
### `func rounded(toPlaces places: Int) -> Float` — *(Float only)*
|
||||
Round to N decimal places.
|
||||
|
||||
```swift
|
||||
Float(3.14159).rounded(toPlaces: 2) // 3.14
|
||||
```
|
||||
|
||||
### Operator `a ** b`
|
||||
Exponentiation, staying in the same type (`Float ** Float → Float`, `Double ** Double → Double`).
|
||||
|
||||
```swift
|
||||
4.4 ** 0.5 // 2.0976…
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>Decimal</b></summary>
|
||||
|
||||
### `mutating func round(_ scale: Int, _ roundingMode:)` / `func rounded(_ scale:, _ roundingMode:) -> Decimal`
|
||||
Decimal rounding via `NSDecimalRound` — mutating and non-mutating.
|
||||
|
||||
```swift
|
||||
Decimal(2.567).rounded(2, .plain) // 2.57
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>BinaryInteger</b></summary>
|
||||
|
||||
### `var bytes: [UInt8]`
|
||||
Big-endian raw byte representation.
|
||||
|
||||
```swift
|
||||
Int16(-128).bytes // [255, 128]
|
||||
```
|
||||
|
||||
### `init?(bytes: [UInt8])`
|
||||
Reconstruct an integer from bytes (traps if the byte count exceeds the type size;
|
||||
`nil` if the value doesn't fit exactly).
|
||||
|
||||
```swift
|
||||
Int16(bytes: [0xFF, 0xFD]) // -3
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>BinaryFloatingPoint</b></summary>
|
||||
|
||||
### `func rounded(numberOfDecimalPlaces: Int, rule: FloatingPointRoundingRule) -> Self`
|
||||
Round to N places with an explicit rule (negative places treated as 0).
|
||||
|
||||
```swift
|
||||
3.1415927.rounded(numberOfDecimalPlaces: 3, rule: .up) // 3.142
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>SignedNumeric</b></summary>
|
||||
|
||||
### `var string: String`
|
||||
`String(describing:)`.
|
||||
|
||||
### `var asLocaleCurrency: String?` / `func asCurrency(locale: Locale = pt_BR) -> String?`
|
||||
Currency formatting in the current locale / a specified locale.
|
||||
|
||||
```swift
|
||||
1234.5.asCurrency() // "R$ 1.234,50"
|
||||
1234.5.asCurrency(locale: Locale(identifier: "en_US")) // "$1,234.50"
|
||||
```
|
||||
|
||||
### `func spelledOutString(locale: Locale = .current) -> String?`
|
||||
Number spelled out in words.
|
||||
|
||||
```swift
|
||||
92.spelledOutString(locale: Locale(identifier: "en")) // "ninety-two"
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>CGFloat</b></summary>
|
||||
|
||||
### `var abs / ceil / floor` / `var int / float / double`
|
||||
Math and numeric conversions.
|
||||
|
||||
```swift
|
||||
CGFloat(-3.2).abs // 3.2
|
||||
CGFloat(3.2).ceil // 4.0
|
||||
```
|
||||
|
||||
### `var isPositive: Bool` / `var isNegative: Bool`
|
||||
Sign checks.
|
||||
|
||||
### `var degreesToRadians: CGFloat` / `var radiansToDegrees: CGFloat`
|
||||
Angle conversion.
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>CGRect</b></summary>
|
||||
|
||||
### `var center: CGPoint`
|
||||
Rect centre.
|
||||
|
||||
### `init(center: CGPoint, size: CGSize)`
|
||||
Build a rect from its centre and size.
|
||||
|
||||
```swift
|
||||
CGRect(center: CGPoint(x: 50, y: 50), size: CGSize(width: 20, height: 10))
|
||||
// origin (40, 45), size 20×10
|
||||
```
|
||||
|
||||
### `func resizing(to size: CGSize, anchor: CGPoint = (0.5, 0.5)) -> CGRect`
|
||||
Resize while keeping the given normalised anchor point fixed.
|
||||
|
||||
```swift
|
||||
rect.resizing(to: CGSize(width: 100, height: 100), anchor: CGPoint(x: 0, y: 1))
|
||||
// grows from the bottom-left corner
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>CGSize</b></summary>
|
||||
|
||||
### `var aspectRatio: CGFloat` / `var maxDimension: CGFloat` / `var minDimension: CGFloat`
|
||||
`width / height` (0 when height is 0), and the larger / smaller side.
|
||||
|
||||
```swift
|
||||
CGSize(width: 16, height: 9).aspectRatio // 1.777…
|
||||
```
|
||||
|
||||
### `func aspectFit(to boundingSize:) -> CGSize` / `func aspectFill(to boundingSize:) -> CGSize`
|
||||
Scale to fit inside / fill a bounding size, preserving ratio.
|
||||
|
||||
```swift
|
||||
CGSize(width: 120, height: 80).aspectFit(to: CGSize(width: 100, height: 50))
|
||||
// 75 × 50
|
||||
```
|
||||
|
||||
### Operators
|
||||
`+`, `-`, `*` and their `+=`/`-=`/`*=` forms, between two `CGSize`s, a `CGSize`
|
||||
and a `(width, height)` tuple, or a `CGSize` and a scalar.
|
||||
|
||||
```swift
|
||||
CGSize(width: 5, height: 10) + CGSize(width: 3, height: 4) // 8 × 14
|
||||
CGSize(width: 5, height: 10) * 3 // 15 × 30
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
<details>
|
||||
<summary><b>CGPoint / CGRect / CGSize — <code>Hashable</code></summary>
|
||||
|
||||
When SwiftUI is available, `CGPoint`, `CGRect`, and `CGSize` are made
|
||||
`Hashable` (retroactive conformance) so they can be used as dictionary keys or
|
||||
in `Set`s and as SwiftUI identifiers.
|
||||
|
||||
```swift
|
||||
var seen: Set<CGPoint> = []
|
||||
seen.insert(CGPoint(x: 1, y: 2))
|
||||
```
|
||||
|
||||
</details>
|
||||
|
||||
## Date, Data & Files
|
||||
|
||||
|
||||
Reference in New Issue
Block a user