快速查找字符串中字符串的所有NSRange的函数

Question

我想在 DNA 序列（字符串）中将所有 CG 字母对设为红色。我可以通过使用 NSMutableAttributedString 来做到这一点。 为此，我需要所有 CG 位置的 NSRange，并且我尝试在下面创建函数，但在

indexesOfStringIn = (stringOut as NSString).rangeOfString(stringIn, options: 0, range: rangeForIndexStringIn) 

rangeOfString 不能使用类型参数列表（字符串，选项：Int，范围：NSRange）调用。哪里出错了？我做错了什么？

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

正如 uchuugaka 所建议的，使用 NSRegularExpression 在字符串中返回匹配范围的数组要容易得多，如下所示：

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

只需为您的 textField 编辑添加一个控制事件，并按如下方式循环遍历范围：

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 } : []
    }
}