.containsString in Swift 2? - swift

Question

Previously, when you wanted to see if your Swift string contained another string, you would cast it to a NSString and call .containsString. Apple, in their infinite wisdom, made this version-aware, so if you try it under S2 it will demand a #available wrapper even if your target platform does support it (which I guess is a bug).

Answer 1

So the best solution appears to be this:
extension String {
func contains(substr: String) -> Bool {
if #available(OSX 10.10, *) {
return NSString(string: self).containsString(substr)
} else {
return self.rangeOfString(substr) != nil
}
}
}
and now to check it, instead of this:
if NSString(string: line).containsString(" ")...
you get to use the much nicer looking:
if line.contains(" ")...
This no longer complains about the version, and (IMHO) looks better too. You almost certainly want this too:
extension String {
var length: Int {
return self.characters.count
}
}
Apple keeps changing the way you get length, and I hope that any future changes to the API will be #available-able, at which point .length can be easily modified. And these are just for sanity:
extension String {
subscript (r: Range<Int>) -> String {
get {
let subStart = advance(self.startIndex, r.startIndex, self.endIndex)
let subEnd = advance(subStart, r.endIndex - r.startIndex, self.endIndex)
return self.substringWithRange(Range(start: subStart, end: subEnd))
}
}
func substring(from: Int) -> String {
let end = self.characters.count
return self[from..<end]
}
func substring(from: Int, length: Int) -> String {
let end = from + length
return self[from..<end]
}
}
extension String {
func trim() -> String {
return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
}
func trim(withSet: NSCharacterSet) -> String {
return self.stringByTrimmingCharactersInSet(withSet)
}
}