Swift Built-in Functions

Function Categories

🔹 Output and Debug Functions

Functions for displaying information and debugging:

// Basic printing
print("Hello, Swift!")
print("Value:", 42)
print("Multiple", "values", "here")

// Print with separator and terminator
print("A", "B", "C", separator: "-", terminator: "!\n")
// Output: A-B-C!

// Debug printing (shows more detail)
let array = [1, 2, 3]
debugPrint(array)  // Shows type information

// Dump - detailed object description
dump(array)
// Shows complete structure

// String interpolation in print
let name = "Swift"
let version = 5.9
print("Welcome to \(name) \(version)!")

🔹 Mathematical Functions

Built-in functions for mathematical operations:

// Basic math functions
let numbers = [-5, 10, 3, -2, 8]

print(abs(-5))           // 5 (absolute value)
print(max(10, 20))       // 20 (maximum)
print(min(10, 20))       // 10 (minimum)
print(max(numbers))      // 10 (maximum in array)

// Advanced math (import Foundation for more)
import Foundation

print(sqrt(16))          // 4.0 (square root)
print(pow(2, 3))         // 8.0 (power)
print(ceil(4.3))         // 5.0 (ceiling)
print(floor(4.7))        // 4.0 (floor)
print(round(4.6))        // 5.0 (round)

// Random numbers
print(Int.random(in: 1...10))      // Random integer 1-10
print(Double.random(in: 0.0...1.0)) // Random double 0-1

🔹 Type Conversion Functions

Convert between different data types:

// String conversions
let number = 42
let text = String(number)        // "42"
let decimal = String(3.14159)    // "3.14159"

// Number conversions
let stringNumber = "123"
let integer = Int(stringNumber)  // Optional(123)
let double = Double("3.14")      // Optional(3.14)

// Safe conversion with nil-coalescing
let safeInt = Int("abc") ?? 0    // 0 (default value)

// Type checking
let value: Any = "Hello"
print(type(of: value))           // String

// Character and ASCII
let char: Character = "A"
let ascii = char.asciiValue      // Optional(65)

// Boolean conversion
let boolFromInt = Bool(truncating: 1)  // true
let boolFromString = Bool("true")      // nil (no direct conversion)

🔹 Collection Functions

Functions for working with arrays and sequences:

// Zip - combine two sequences
let names = ["Alice", "Bob", "Charlie"]
let ages = [25, 30, 35]
let combined = zip(names, ages)

for (name, age) in combined {
    print("\(name) is \(age) years old")
}

// Stride - create number sequences
for i in stride(from: 0, to: 10, by: 2) {
    print(i)  // 0, 2, 4, 6, 8
}

for i in stride(from: 10, through: 0, by: -2) {
    print(i)  // 10, 8, 6, 4, 2, 0
}

// Repeat element
let repeated = repeatElement("Swift", count: 3)
let array = Array(repeated)  // ["Swift", "Swift", "Swift"]

// Sequence functions
let numbers = [1, 2, 3, 4, 5]
print(numbers.count)         // 5
print(numbers.isEmpty)       // false
print(numbers.first)         // Optional(1)
print(numbers.last)          // Optional(5)

🔹 String Functions

Built-in functions for string manipulation:

let text = "Hello, Swift!"

// String properties and methods
print(text.count)                    // 13 (character count)
print(text.isEmpty)                  // false
print(text.uppercased())             // "HELLO, SWIFT!"
print(text.lowercased())             // "hello, swift!"

// String checking
print(text.hasPrefix("Hello"))       // true
print(text.hasSuffix("Swift!"))      // true
print(text.contains("Swift"))        // true

// String manipulation
let trimmed = "  spaces  ".trimmingCharacters(in: .whitespaces)
print(trimmed)                       // "spaces"

// String components
let words = text.components(separatedBy: " ")
print(words)                         // ["Hello,", "Swift!"]

// Character operations
for char in text {
    if char.isLetter {
        print(char, terminator: "")  // HelloSwift
    }
}

🔹 Memory and Performance Functions

Functions for memory management and performance:

// Memory size functions
print(MemoryLayout.size)        // 8 (bytes)
print(MemoryLayout.stride)   // Memory stride

// Swap function
var a = 10
var b = 20
swap(&a, &b)
print(a, b)  // 20, 10

// Assert functions (debug builds only)
let age = 25
assert(age >= 0, "Age cannot be negative")

// Precondition (always checked)
precondition(age >= 0, "Age must be positive")

// Fatal error (terminates program)
// fatalError("Something went wrong")

// Measure execution time
import Foundation
let startTime = CFAbsoluteTimeGetCurrent()
// ... some code ...
let timeElapsed = CFAbsoluteTimeGetCurrent() - startTime
print("Time elapsed: \(timeElapsed) seconds")