Basic String Operations

 Basic String Operations

• Creating Strings: You can create strings using double quotes, like "Hello, world!". Swift also allows multi-line strings using triple quotes, which is useful for longer texts or code snippets.

• Concatenation: To combine strings, you use the + operator. For example, "Hello" + " " + "World" results in "Hello World". You can also use string interpolation with \() to insert variables or expressions inside strings, such as "The score is \(score)".

• Appending: You can add more text to an existing string using the append() method or the += operator. For example, myString.append(" Text") or myString += " Text" will add " Text" to myString.

• Length: To find out how many characters are in a string, use the count property, like myString.count, which gives you the number of characters.

• Accessing Characters: Swift strings are indexed by integer positions. To access a character at a specific position, use myString[index], where index is the position you’re interested in. For example, myString[myString.index(myString.startIndex, offsetBy: 2)] accesses the third character of myString.

• Substrings: You can extract parts of a string using ranges. For example, myString[myString.startIndex..<myString.index(myString.startIndex, offsetBy: 5)] gets the first five characters.

• Uppercase and Lowercase: Convert strings to all uppercase or lowercase using uppercased() and lowercased() methods, like "hello".uppercased() which gives "HELLO".

• Trimming: Remove unwanted spaces from the beginning and end of a string with trimmingCharacters(in: .whitespaces), useful for cleaning up user input.

• Checking Prefixes and Suffixes: Use hasPrefix(_:) and hasSuffix(_:) to check if a string starts or ends with a particular substring.

CODE EXAMPLE:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {

        super.viewDidLoad()

        

        // Creating Strings

        let singleLineString = "Hello, world!"

        let multiLineString = """

        This is a multi-line string

        that spans several lines.

        """

        

        // Concatenation

        let firstPart = "Hello"

        let secondPart = "World"

        let combinedString = firstPart + " " + secondPart

        

        // String Interpolation

        let score = 42

        let interpolatedString = "The score is \(score)"

        

        // Appending

        var myString = "Hello"

        myString.append(" World")

        myString += "!"

        

        // Length

        let length = myString.count

        

        // Accessing Characters

        let index = myString.index(myString.startIndex, offsetBy: 3)

        let thirdCharacter = myString[index]

        

        // Substrings

        let startIndex = myString.startIndex

        let endIndex = myString.index(startIndex, offsetBy: 5)

        let substring = myString[startIndex..<endIndex]

        

        // Uppercase and Lowercase

        let uppercaseString = myString.uppercased()

        let lowercaseString = myString.lowercased()

        

        // Trimming

        let rawString = "   Trim me   "

        let trimmedString = rawString.trimmingCharacters(in: .whitespaces)

        

        // Checking Prefixes and Suffixes

        let hasHelloPrefix = myString.hasPrefix("Hello")

        let hasWorldSuffix = myString.hasSuffix("World")

        

        // Printing results to console

        print("Single Line String: \(singleLineString)")

        print("Multi Line String: \(multiLineString)")

        print("Combined String: \(combinedString)")

        print("Interpolated String: \(interpolatedString)")

        print("Appended String: \(myString)")

        print("Length of String: \(length)")

        print("Third Character: \(thirdCharacter)")

        print("Substring: \(substring)")

        print("Uppercase String: \(uppercaseString)")

        print("Lowercase String: \(lowercaseString)")

        print("Trimmed String: \(trimmedString)")

        print("Has 'Hello' Prefix: \(hasHelloPrefix)")

        print("Has 'World' Suffix: \(hasWorldSuffix)")

    }

}