Regular expression (Swift)

Lesson

1. Match string using regular expression

Use regular expression pattern \\d{3}-(\\d{4})-\\d{2} to match string 123-4567-89

Return match result: ’"123-4567-89" and ’4567’

2. Replace string using regular expression pattern

Use regular expression pattern (\\d+)-(\\d+)-(\\d+) to match string 123-4567-89

Use pattern string "$3-$1-$2" to replace match result, return result "89-123-4567".

3. Replace string using regular expression callback

Use regular expression pattern \\d+ to match string 123-4567-89

Replace match result (three numbers) by reversing them, return result "321-7654-98".

4. Split string using regular expression

Use regular expression pattern %(%begin|next|end)% to split string "%begin%hello%next%world%end%".

Return split result: "hello" and "world" in between the regular expression delimiters.

Swift

import Foundation let s = "123-4567-89,987-6543-21" let r = try NSRegularExpression(pattern: #"\d{3}-(\\d{4})-\\d{2}"#) let results = r.matches(in: s, range: NSRange(s.startIndex..., in: s)) for (i, m) in results.enumerated() { for j in 0..




let r2 = try NSRegularExpression(pattern: #"(\d+)-(\d+)-(\d+)"#)
let s2 = r2.stringByReplacingMatches(in: s, range: NSRange(s.startIndex..., in: s), withTemplate: "$3-$1-$2")
print(s2)




let r3 = try NSRegularExpression(pattern: #"\d+"#)
let results2 = r3.matches(in: s, range: NSRange(s.startIndex..., in: s))
var s3 = s
for i in (0..



// https://stackoverflow.com/questions/25818197/how-to-split-a-string-in-swift
extension String {
    
    func split(regex pattern: String) -> [String] {
        
        guard let re = try? NSRegularExpression(pattern: pattern, options: [])
            else { return [] }
        
        let nsString = self as NSString // needed for range compatibility
        let stop = 
        let modifiedString = re.stringByReplacingMatches(
            in: self,
            range: NSRange(location: 0, length: nsString.length),
            withTemplate: stop)
        return modifiedString.components(separatedBy: stop)
    }
}




let r4 = "%(begin|next|end)%"
let s4 = "%begin%hello%next%world%end%"
print(s4.split(regex: r4))




group 0,0 : 123-4567-89  
group 0,1 : 4567  
group 1,0 : 987-6543-21  
group 1,1 : 6543  
89-123-4567,21-987-6543  
321-7654-98,789-3456-12  
["", "hello", "world", ""]



Using third-party libraries
Using standard regular expressions in Swift is cumbersome
Use third-party library CrossroadRegex


import Foundation

let s = "123-4567-89,987-6543-21"
let r = #"\d{3}-(\\d{4})-\\d{2}"#.r!
r.findAll(in: s).enumerated().forEach { (i, m) in
    for j in 0..



let r2 = #"(\d+)-(\d+)-(\d+)"#.r!
let s2 = r2.replaceAll(in: s, with: "$3-$1-$2")
print(s2)




let r3 = #"\d+"#.r!
let s3 = r3.replaceAll(in: s) { String($0.matched.reversed()) }
print(s3)




let r4 = "%(?:begin|next|end)%".r!
let s4 = "%begin%hello%next%world%end%"
print(r4.split(s4))




group 0,0 : 123-4567-89  
group 0,1 : 4567  
group 1,0 : 987-6543-21  
group 1,1 : 6543  
89-123-4567,21-987-6543  
321-7654-98,789-3456-12  
["", "hello", "world", ""]

Thành phố Cuồng loạn

Regular expression (Swift)

Lesson

Swift

Using third-party libraries

Thẻ Phổ Biến