Regular expressions in Swift

[mephistophele-s]

No description provided.

[Gagnant]

@anastasiaSTR,

1. Please check your Match sample. [0-9] will match only single digits, maybe it should be [0-9]+ to match numbers.
2. Check you Split sample. If original string is Th//is-is-st, splitter is -, stop is //. The string will be splitted in [th, is, is, st] which is wrong.

[GreatAndPowerfulKing]

I supposed "Cating" should be "Casting". And maybe not "special" but "specific".

[GreatAndPowerfulKing]

If you are not stopping an execution on NSRegularExpression initialization failure, you may replace replaceRegExp declaration with: let replaceRegExp = try? NSRegularExpression(pattern: "World", options: .allowCommentsAndWhitespace).

[Gagnant]

@anastasiaSTR, check this implementation. Feel free to ask me some questions.

extension String {
	
	private var range: NSRange {
		return NSMakeRange(0, self.utf16.count)
	}
	
	private var stringBegin: NSRange {
		return NSMakeRange(0, 0)
	}
	
	private var stringEnd: NSRange {
		return NSMakeRange(utf16.count, 0)
	}
	
	public func components(separatedBy regex: NSRegularExpression) -> [String] {
		let matchedRanges = regex.matches(in: self, range: self.range).map {
			return $0.range
		}
		return zip(matchedRanges + [stringEnd], [stringBegin] + matchedRanges).flatMap { next, current -> String? in
			let start = String.UTF16Index(current.location + current.length)
			let end = String.UTF16Index(next.location)
			return String(utf16[start ..< end])
		}.flatMap {
			$0.isEmpty ? nil : $0
		}
	}
	
}

You may use it in following manner.

let targetString = "This-is-string-to-split-by-sp//ecial-character"

if let regex = try? NSRegularExpression(pattern: "-") {
	print(targetString.components(separatedBy: regex))
}

[Gagnant]

I propose you to omit options parameter because it has default value []

[Gagnant]

You must use testString.utf16.count here. Because NSRegularExpression works with NSString, which are utf16 encoded.