Swift String Manipulation

String manipulation is a crucial skill for Swift developers. It involves modifying, combining, and extracting information from text data. Swift provides powerful tools for working with strings efficiently.

String Basics

In Swift, strings are represented by the String type. They are value types, which means they are copied when assigned to a new variable or passed as an argument to a function.

Creating Strings

You can create strings using string literals or by initializing a String instance:

let greeting = "Hello, World!"
let emptyString = String()
    

String Concatenation

Swift offers multiple ways to combine strings:

1. Using the + Operator

let firstName = "John"
let lastName = "Doe"
let fullName = firstName + " " + lastName
print(fullName) // Output: John Doe
    

2. String Interpolation

String interpolation allows you to include expressions directly within string literals:

let age = 30
let message = "I am \(age) years old."
print(message) // Output: I am 30 years old.
    

Common String Operations

Accessing Characters

Swift strings are collections of characters. You can access individual characters using subscript notation:

let str = "Swift"
let firstChar = str[str.startIndex]
print(firstChar) // Output: S
    

Substring Extraction

To extract a portion of a string, use the String.Index type:

let text = "Hello, Swift!"
let index = text.index(text.startIndex, offsetBy: 7)
let substring = text[..

var greeting = "Hello"
greeting.append(", World!")
print(greeting) // Output: Hello, World!

greeting.insert("!", at: greeting.endIndex)
print(greeting) // Output: Hello, World!!

greeting.removeAll()
print(greeting) // Output: (empty string)
    

let str1 = "Hello"
let str2 = "hello"

print(str1 == str2) // Output: false
print(str1.lowercased() == str2.lowercased()) // Output: true
print(str1.hasPrefix("He")) // Output: true
print(str2.hasSuffix("lo")) // Output: true