如何从完整字符串 iOS swift 中查找字符串的多个 NSRange

Question

let fullString = "Hello world, there are \(string(07)) continents and \(string(195)) countries."
let range = [NSMakeRange(24,2), NSMakeRange(40,3)]

需要在整个完整字符串中找到数字的 NSRange，并且两个数字有可能相同。目前硬编码如上所示，消息可以是动态的，其中硬编码值会出现问题。

我已拆分字符串并尝试获取 NSRange，因为可能存在相同的值。像 stringOne 和 stringTwo。

func findNSMakeRange(initialString:String, fromString: String) {
        let fullStringRange = fromString.startIndex..<fromString.endIndex
        fromString.enumerateSubstrings(in: fullStringRange, options: NSString.EnumerationOptions.byWords) { (substring, substringRange, enclosingRange, stop) -> () in
            let start = distance(fromString.startIndex, substringRange.startIndex)
            let length = distance(substringRange.startIndex, substringRange.endIndex)
            let range = NSMakeRange(start, length)

            if (substring == initialString) {
                print(substring, range)
            }
        })
    }

收到类似 Cannot invoke distance with an argument list of type (String.Index, String.Index)

的错误

谁有更好的解决方案？

Answer 1

您说您想要遍历字符串中的 NSRange 个匹配项，以便您可以将粗体属性应用于相关的子字符串。您可以使用 NSRegularExpression 来做到这一点：

let range = NSRange(location: 0, length: string.count)
try! NSRegularExpression(pattern: "[0-9]+").enumerateMatches(in: string, range: range) { result, _, _ in
    guard let range = result?.range else { return }
    attributedString.setAttributes(boldAttributes, range: range)
}

就我个人而言，我发现有一个方法可以 return 一个 Swift 范围的数组，即 [Range<String.Index>]:

extension StringProtocol {
    func ranges<T: StringProtocol>(of string: T, options: String.CompareOptions = []) -> [Range<Index>] {
        var ranges: [Range<Index>] = []
        var start: Index = startIndex
        
        while let range = range(of: string, options: options, range: start ..< endIndex) {
            ranges.append(range)
            
            if !range.isEmpty {
                start = range.upperBound               // if not empty, resume search at upper bound
            } else if range.lowerBound < endIndex {
                start = index(after: range.lowerBound) // if empty and not at end, resume search at next character
            } else {
                break                                  // if empty and at end, then quit
            }
        }
        
        return ranges
    }
}

然后就可以这样使用了:

let string = "Hello world, there are 09 continents and 195 countries."
let ranges = string.ranges(of: "[0-9]+", options: .regularExpression)

然后你可以 map Range 到 NSRange。回到最初的例子，如果你想让这些数字在一些属性字符串中加粗：

string.ranges(of: "[0-9]+", options: .regularExpression)
    .map { NSRange([=13=], in: string) }
    .forEach { attributedString.setAttributes(boldAttributes, range: [=13=]) }

如何从完整字符串 iOS swift 中查找字符串的多个 NSRange

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