Regular expressions in Swift

Swift/match.playground/Contents.swift

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+import Foundation
+
+let testString = "one 1 two 2 three 3"
+
+let pattern = "[0-9]" // Matching numbers
+let nsString = testString as NSString // Cating to NSString to use special methods
+
+// Trying to initialize regex
+do {
+    let regex = try NSRegularExpression(pattern: pattern, options: [])
+    let results = regex.matches(in: testString, options: [], range: NSMakeRange(0, testString.characters.count)) // Matches
+    let result = results.map { nsString.substring(with: $0.range) }
+    print(result)
+} catch let error as NSError { // Handling exception
+    print("Invalid regex: \(error.localizedDescription)")
+}
+
+
+

Swift/match.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

Swift/replace.playground/Contents.swift

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+import Foundation
+
+let helloString = "Hello, World!" // Defining initial string
+
+// Initializing regular expression
+var replaceRegExp: NSRegularExpression?
+
+do {
+    replaceRegExp = try NSRegularExpression(pattern: "World", options: .allowCommentsAndWhitespace)
+} catch let error as NSError { // Handling exception
+    print(error.localizedDescription)
+}
+
+// Initializing new string with substring, replaced by template
+let newString = replaceRegExp?.stringByReplacingMatches(in: helloString, options: .withTransparentBounds, range: NSRange(location: 0, length: helloString.characters.count), withTemplate: "Kitten")
+
+print(newString ?? "Replacing failed", "\n")

Swift/replace.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

Swift/split.playground/Contents.swift

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+import Foundation
+
+let initialString = "This-is-string-to-split-by-special-character" // Defining initial string
+
+let splitter = "-" // Defining splitter
+let stop = "//"
+
+// Initializing regular expression
+var splitRegExp: NSRegularExpression?
+do {
+    splitRegExp = try NSRegularExpression(pattern: splitter, options: .allowCommentsAndWhitespace)
+} catch let error as NSError { // Handling exception
+    print(error.localizedDescription)
+}
+
+let modifiedString = splitRegExp?.stringByReplacingMatches(in: initialString, options: .withTransparentBounds, range: NSRange(location: 0, length: initialString.characters.count), withTemplate: stop)
+
+// But in Swift this method can be used
+print(modifiedString?.components(separatedBy: stop) ?? "Splitting failed", "\n")

Swift/split.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>