Question

我有一个文件路径......

/acme101/acmeX100/acmeX100.008.png

我可以使用它来获取扩展程序.png in this case

let leftSide =  (lhs.fnName as NSString).pathExtension

这是获取文件名acmeX100

let leftSide =  (lhs.fnName as NSString).lastPathComponent

但是我想要中间位......在这种情况下是008？

有一个漂亮的衬垫吗？

Answer 1

假设文件路径采用了这种通用形式，那么（几乎）是一个单行（我喜欢安全地玩）：

var filePath = "/acme101/acmeX100/acmeX100.008.png"

func extractComponentBetweenDots(inputString: String) -> String? {

    guard inputString.components(separatedBy: ".").count > 2  else { print("Incorrect format") ; return nil } // Otherwise not in the correct format, you caa add other tests

    return inputString.components(separatedBy: ".")[inputString.components(separatedBy: ".").count - 2]

}

使用如下：

if let extractedString : String = extractComponentBetweenDots(inputString: filePath) {
    print(extractedString)
}

Answer 2

我想用你问题中的相同技术做一个例子 - 尽管向NSString的向下转换使整个事情变得相当丑陋，但它的工作效率却很高。这是在Swift 3中，但如果需要，可以很容易地将它移植回Swift 2。

func getComponents(from str: String) -> (name: String, middle: String, ext: String) {
    let compo = (str as NSString).lastPathComponent as NSString
    let ext = compo.pathExtension
    let temp = compo.deletingPathExtension as NSString
    let middle = temp.pathExtension
    let file = temp.deletingPathExtension
    return (name: file, middle: middle, ext: ext)
}

let result = getComponents(from: "/acme101/acmeX100/acmeX100.008.png")

print(result.name) // "acmeX100"
print(result.middle) // "008"
print(result.ext) // "png"

如果你只需要中间部分：

func pluck(str: String) -> String {
    return (((str as NSString).lastPathComponent as NSString).deletingPathExtension as NSString).pathExtension
}

pluck(str: "/acme101/acmeX100/acmeX100.008.png") // "008"

Answer 3

Bon，

明智地感谢您的回答。我最终得到了这个......这是相同但又不同的。

func pluck(str:String) -> String {
    if !str.isEmpty {
        let bitZero = str.characters.split{$0 == "."}.map(String.init)
        if (bitZero.count > 2) {
            let bitFocus = bitZero[1]
            print("bitFocus \(bitFocus)")
            return(bitFocus)
        }
    }
    return("")
}

路径提取swift 3.0

3 个答案: