function to find all NSRanges for a string in string in swift - swift

Question

I would like to have all CG letters pairs in red color in DNA sequences (string). I can do it by using NSMutableAttributedString.
For this I need NSRanges of all CG positions and I have tried to make the function below but in the line
indexesOfStringIn = (stringOut as NSString).rangeOfString(stringIn, options: 0, range: rangeForIndexStringIn)
rangeOfString with range cannot be invoked with an argument list of type (String, options: Int, range: NSRange). Where is a mistake ? What i did wrong ?
func searchForNSRangesOfStringInString(stringOut: String, stringIn: String) -> [NSRange]
{
var arrayOfindexesOfStringIn = [NSRange]()
if stringIn.characters.count > 1
{
var rangeNS = (stringOut as NSString).rangeOfString(stringIn)
if rangeNS.location != NSNotFound
{
let endIndexOfStringOut = (stringOut as NSString).length - 1
var indexesOfStringIn = (stringOut as NSString).rangeOfString(stringIn)
arrayOfindexesOfStringIn = [indexesOfStringIn]
var lastIndexOfStringIn = (stringOut as NSString).rangeOfString(stringIn).location
var rangeForIndexStringIn = NSRange(lastIndexOfStringIn...endIndexOfStringOut)
while indexesOfStringIn.location != NSNotFound
{
indexesOfStringIn = (stringOut as NSString).rangeOfString(stringIn, options: 0, range: rangeForIndexStringIn)
if indexesOfStringIn.location != NSNotFound
{
arrayOfindexesOfStringIn.append(indexesOfStringIn)
lastIndexOfStringIn = (stringOut as NSString).rangeOfString(stringIn, options: 0, range: rangeForIndexStringIn).location
rangeForIndexStringIn = NSRange(lastIndexOfStringIn...endIndexOfStringOut)
}
}
}
}
return arrayOfindexesOfStringIn
}

Answer 1

As suggested by uchuugaka it is much easier to use NSRegularExpression to return an array of the matches ranges in a string as follow:
extension String {
func findOccurencesOf(text text:String) -> [NSRange] {
return !text.isEmpty ? try! NSRegularExpression(pattern: text, options: []).matchesInString(self, options: [], range: NSRange(0..<characters.count)).map{ $0.range } : []
}
}
let str = "CGCGCGCGCG"
let ranges = str.findOccurencesOf(text: "CG")
print(ranges.count) // 5
Just add a control event for your textField Editing changed and loop through the ranges as follow:
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var textField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
textField.addTarget(self, action: "coloring:", forControlEvents: UIControlEvents.EditingChanged)
textField.becomeFirstResponder()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func coloring(sender:UITextField) {
let attText = NSMutableAttributedString(string: sender.text ?? "")
let ranges = sender.text!.uppercaseString.findOccurencesOf(text: "CG")
for range in ranges {
attText.addAttributes([NSForegroundColorAttributeName : UIColor.redColor()], range: range)
}
sender.attributedText = attText
}
}
extension String {
func findOccurencesOf(text text:String) -> [NSRange] {
return !text.isEmpty ? try! NSRegularExpression(pattern: text, options: []).matchesInString(self, options: [], range: NSRange(0..<characters.count)).map{ $0.range } : []
}
}