Swift:
Using regular expressions
How to:
Swift native support for regex utilizes the NSRegularExpression class, alongside the String class’s range and replacement methods. Below is an example of using regex to find and highlight email addresses within a text block:
import Foundation
let text = "Contact us at [email protected] or [email protected] for more information."
let regexPattern = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
do {
let regex = try NSRegularExpression(pattern: regexPattern)
let matches = regex.matches(in: text, range: NSRange(text.startIndex..., in: text))
if !matches.isEmpty {
for match in matches {
let range = Range(match.range, in: text)!
print("Found: \(text[range])")
}
} else {
print("No matches found.")
}
} catch {
print("Regex error: \(error.localizedDescription)")
}
// Sample Output:
// Found: [email protected]
// Found: [email protected]For more complex or convenience-focused scenarios, you can use third-party libraries such as SwiftRegex, which simplifies syntax and expands possibilities. Though Swift’s standard library is powerful, some developers favor these libraries for their concise syntax and additional features. Here’s how you might perform a similar task using a hypothetical third-party library:
// Assuming a library called SwiftRegex exists and is imported
let text = "Reach out at [email protected] or visit our website."
let emailPattern = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
let emails = text.matches(for: emailPattern) // Hypothetical method provided by SwiftRegex
if emails.isEmpty {
print("No email addresses found.")
} else {
emails.forEach { email in
print("Found: \(email)")
}
}
// Hypothetical output assuming the `matches(for:)` method exists in SwiftRegex:
// Found: [email protected]This example illustrates using a third-party regular expression package to simplify finding matches within a string, assuming such convenience methods like matches(for:) exist. It’s important to refer to the respective third-party library documentation for accurate syntax and method availability.