Syntax example scan sheet for Swift.

swift_up_to_speed.swift

// Swift up to speed

import Foundation

// variables and constants
var integerVar: Int = 10
let stringVar: String = "Hello, Swift!"

// functions
func greet(name: String) -> String {
    return "Hello \(name)!"
}

// for-in loop
for i in 1...5 {
    print("For loop iteration: \(i)")
}

// while loop
var count = 5
while count > 0 {
    print("While loop iteration: \(count)")
    count -= 1
}

// conditional statements
if integerVar > 5 {
    print("Integer is greater than 5")
} else if integerVar == 5 {
    print("Integer is 5")
} else {
    print("Integer is less than 5")
}

// data structures
var numbers: [Int] = [1, 2, 3, 4, 5]
var dictionary: [String: Int] = ["a": 1, "b": 2]

// optionals
var optionalString: String? = "This is optional"
if let safeString = optionalString {
    print("Unwrapped optional: \(safeString)")
} else {
    print("Optional was nil")
}

// error handling
enum FileError: Error {
    case fileNotFound, unreadable, encodingFailed
}

func readFile(path: String) throws -> String {
    guard let data = FileManager.default.contents(atPath: path) else {
        throw FileError.fileNotFound
    }
    guard let content = String(data: data, encoding: .utf8) else {
        throw FileError.encodingFailed
    }
    return content
}

// file I/O
let filePath = "example.txt"
do {
    let content = try readFile(path: filePath)
    print("File content: \(content)")
} catch {
    print("An error occurred: \(error)")
}

// concurrency
DispatchQueue.global().async {
    print("This is running on a background thread")
    DispatchQueue.main.async {
        print("Back on the main thread")
    }
}

// main
print(greet(name: "World"))