Data types in swift?

Overview

Swift is Apple's programming language for iOS, macOS, watchOS, and tvOS development. It has a rich, type-safe system with both value types (struct-based) and reference types (class-based).

Swift Data Types

Basic Types

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// Integer types
var age: Int = 25          // Platform-native (64-bit on modern iOS)
var byte: Int8 = 127       // -128 to 127
var small: Int16 = 32767
var medium: Int32 = 2_147_483_647
var large: Int64 = 9_223_372_036_854_775_807

// Unsigned
var count: UInt = 10       // Unsigned Int
var uByte: UInt8 = 255

// Floating point
var height: Double = 5.11  // 64-bit (preferred)
var price: Float = 9.99    // 32-bit

// Boolean
var isActive: Bool = true

// String
var name: String = "Alice"
// Multi-line string (triple-quote in Swift)
var multiLine = """
  Hello,
  World!
"""

// Character
var letter: Character = "A"

Collections

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// Array
var fruits: [String] = ["apple", "banana", "cherry"]
let ages: [Int] = [25, 30, 35]

// Dictionary (Map equivalent)
var scores: [String: Int] = ["Alice": 95, "Bob": 87]

// Set (unique values)
var tags: Set<String> = ["swift", "ios", "apple"]

// Tuple (multiple values without a struct)
let person: (String, Int) = ("Alice", 28)
let named = (name: "Bob", age: 30)
print(named.name) // Bob

Optional (Nullable)

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var email: String? = nil   // Optional -- can be nil
var phone: String? = "9876543210"

// Unwrapping
if let phone = phone {
  print("Phone: \(phone)")
}

// Nil coalescing (?? equivalent in Swift)
let displayPhone = phone ?? "No phone"

// Force unwrap (dangerous -- crash if nil)
print(phone!)

Swift vs Dart Type Mapping

Int

int

Double

double

Float

String

String

Bool

bool

[T]

List<T>

[K:V]

Map<K,V>

Set<T>

Set<T>

T?

T?

Tuple

Record

Any

dynamic

Key Difference: Swift has value types (

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struct

,

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enum

, tuples) and reference types (

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class

). Dart's basic types are all objects -- no primitive types.