Question

我正在更新swift 3中的代码。将Range转换为NSRange时出错。如何在swift 3中做到这一点？

func nsRange(_ range : Range<String.Index>) -> NSRange {
    let utf16from = String.UTF16View.Index(range.lowerBound, within: utf16)
    let utf16to   = String.UTF16View.Index(range.upperBound,   within: utf16)
    return NSRange(location: utf16.startIndex.distanceTo(utf16from), length: utf16from.distanceTo(utf16to))
}

Answer 1

Xcode 10.2•Swift 5

extension StringProtocol {
    func nsRange(from range: Range<Index>) -> NSRange {
        return .init(range, in: self)
    }
}

let string = "Hello USA  !!! Hello World !!!"

if let range = string.range(of: "Hello World") {
    let nsRange = string.nsRange(from: range)
    (string as NSString).substring(with: nsRange) //  "Hello World"
}

您还可以创建扩展nsRange(of:)的相应StringProtocol方法：

extension StringProtocol {
    func nsRange(of string: Self, options: String.CompareOptions = [], range: Range<Index>? = nil, locale: Locale? = nil) -> NSRange? {
        guard let range = self.range(of: string, options: options, range: range ?? startIndex..<endIndex, locale: locale ?? .current) else { return nil }
        return .init(range, in: self)
    }
    func nsRanges(of string: Self, options: String.CompareOptions = [], range: Range<Index>? = nil, locale: Locale? = nil) -> [NSRange] {
        var start = range?.lowerBound ?? startIndex
        let end = range?.upperBound ?? endIndex
        var ranges: [NSRange] = []
        while start < end, let range = self.range(of: string, options: options, range: start..<end, locale: locale ?? .current) {
            ranges.append(.init(range, in: self))
            start = range.upperBound
        }
        return ranges
    }
}

let string = "Hello USA  !!! Hello World !!!"

if let nsRange = string.nsRange(of: "Hello World") {
    (string as NSString).substring(with: nsRange) //  "Hello World"
}
let nsRanges = string.nsRanges(of: "Hello")
print(nsRanges)   // "[{0, 5}, {19, 5}]\n"

如何转换NSRange中的范围？

1 个答案: