Swift Implementation of Regex built on NSRegularExpression

What's New

Swift 4.2 Support


Updates SwiftExpression to Swift v4.2

Build Status Carthage compatible


Swift Expression is a Regex framework built with Swift to make it easier to work with NSRegularExpression. The framework provides low overhead to work with pattern matching.


There is not a native Regex implemenation in Swift or Objective-C as there is in other languages such as javascript or ruby. This framework's goal is to make it easier to work with Regex in a "Swifty" way. The framework is built on NSRegularExpression with just easy to call methods and easy objects to work with. To feel as native as possible the Swift String type has been extended with new methods for Regex.


Xcode 10.2

Swift 4.2

iOS 8.0+

Code Example

Create a Regex object

A Regex can be created multiple ways.

Failable Initializer
if let regex = Regex("^\\d") {
  // use regex object
Prefix operator

The prefix operator is used as a way to initialize a regex struct and is built on the failable initalizer.

if let regex = <>"^\\d" {
  // use regex object
Infix operator

Use the custom infix to check for a match.

let str = "333-aa-bb"
let regexPatternStr = "^\\d"

// string to search in on left hand side, regex pattern in string format on right hand side
if str ~= regexPatternStr {
  // a match is in the string continue processing
} else {
  // failed to find a single match in string
String extension methods


let match = str.match(regex) // Returns a Regex.Match struct
match.components // Returns a collection of tuples that are the substring match and range of the match [(String, Range<String.Index>)]
match.subStrings() // Returns a collection of the substring matches [String]
match.ranges() // Returns a collection of ranges of the matches [Range<String.Index>]


str.replace(regex, with: replaceStr) // Returns a new string with matches replaced with replacement string


str.find(regex) // Returns true if a match exists in the string


@available(iOS 8, *)


You can use Cocoapods to install SwiftExpression by adding it to your Podfile:

platform :ios, '8.0'

target 'MyApp' do
  pod 'SwiftExpression'


You can use Carthage to install SwiftExpression by adding it to your Cartfile:

github "lostatseajoshua/SwiftExpression"

Swift Package Manager

import PackageDescription

let package = Package(
    name: "YourProject",
    targets: [],
    dependencies: [
        .Package(url: "https://github.com/lostatseajoshua/SwiftExpression.git",
                 majorVersion: 2),


To use this library in your project manually do the following.

Add the SwiftExpression.framework to your project by downloading the framework from the releases


Checkout this demo project that was built with SwiftExpression. It highlights text in a UITextView using regex pattern that is inputted into a UITextField!

Demo Github project


Joshua Alvarado - Twitter - Website


This project is released under the MIT license.


  • Swift Tools 4.2.0
View More Packages from this Author


  • None
Last updated: Wed May 24 2023 07:28:12 GMT-0500 (GMT-05:00)