Swift Language NSRegularExpression in Swift Basic Usage
Example
There are several considerations when implementing Regular Expressions in Swift.
let letters = "abcdefg"
let pattern = "[a,b,c]"
let regEx = try NSRegularExpression(pattern: pattern, options: [])
let nsString = letters as NSString
let matches = regEx.matches(in: letters, options: [], range: NSMakeRange(0, nsString.length))
let output = matches.map {nsString.substring(with: $0.range)}
//output = ["a", "b", "c"]
In order to get an accurate range length that supports all character types the input string must be converted to a NSString.
For safety matching against a pattern should be enclosed in a do catch block to handle failure
let numbers = "121314"
let pattern = "1[2,3]"
do {
let regEx = try NSRegularExpression(pattern: pattern, options: [])
let nsString = numbers as NSString
let matches = regEx.matches(in: numbers, options: [], range: NSMakeRange(0, nsString.length))
let output = matches.map {nsString.substring(with: $0.range)}
output
} catch let error as NSError {
print("Matching failed")
}
//output = ["12", "13"]
Regular expression functionality is often put in an extension or helper to seperate concerns.
