how i get an int from string? - ios

Question

am working on a weather app and i want to generate the image according to the degrees number witch is in a string so how can i extract the number from string
this is the string:
Mostly dry. Very mild (max 19ºC on Sat afternoon, min 15ºC on Sunnight). Wind will be generally light.
#IBAction func weatherButton(sender: UIButton) {
let url = NSURL(string: "http://www.weather-forecast.com/locations/" + cityNameTextField.text.stringByReplacingOccurrencesOfString(" ", withString: "-") + "/forecasts/latest")
if url != nil {
let task = NSURLSession.sharedSession().dataTaskWithURL(url!){ (data, response, error) in
var urlError = false
var weather = ""
if error == nil {
var urlContent = NSString(data: data, encoding: NSUTF8StringEncoding)
var urlContentArray = urlContent!.componentsSeparatedByString("<span class=\"phrase\">")
if urlContentArray.count > 0 {
var weatherArray = urlContentArray[1].componentsSeparatedByString("</span>")
weather = weatherArray[0] as! String
weather = weather.stringByReplacingOccurrencesOfString("°", withString: "º")
println(weather)
}
else {
urlError = true
}
}
else {
urlError = true
}
dispatch_async(dispatch_get_main_queue()) {
if urlError == true {
self.showError()
}
else {
self.weatherFact.text = weather
}
}
}
task.resume()
}
else {
showError()
}
}

Answer 1

Another solution using NSRegularExpression.
The result is an Array of the numbers and the regex considers also temperatures below zero
For Swift 1.2:
let string = "Mostly dry. Very mild (max -19ºC on Sat afternoon, min 15ºC on Sunnight). Wind will be generally light."
let regex = NSRegularExpression(pattern: "-?[0-9]{1,3}", options: NSRegularExpressionOptions(), error: nil)
if let matches = regex?.matchesInString(string, options: NSMatchingOptions(), range: NSRange(location:0, length:count(string))) {
let degrees = matches.map {return (string as NSString).substringWithRange($0.range).toInt()! }
println(degrees) // -> [-19, 15]
}
For Swift 2.0:
let string = "Mostly dry. Very mild (max -19ºC on Sat afternoon, min 15ºC on Sunnight). Wind will be generally light."
do {
let regex = try NSRegularExpression(pattern: "-?[0-9]{1,3}", options: NSRegularExpressionOptions())
let matches = regex.matchesInString(string, options: NSMatchingOptions(), range: NSRange(location: 0, length: string.characters.count))
let degrees = matches.map {Int((string as NSString).substringWithRange($0.range))!}
print(degrees) // -> [-19, 15]
}
catch {
print("NSRegularExpression threw error: \(error)")
}