swift - 字符串替换没有 NSString API 的子字符串

Question

我希望能够在不桥接到 NS 类的情况下查找和替换 native Swift 字符串中出现的子字符串。我怎样才能做到这一点？

这不是 this question 的副本，因为这个问题是关于替换单个字符的。这道题是关于查找和替换一个可能包含很多字符的子串。

Answer 1

没有基础的方法:

extension String {
    func replacing(_ oldString: String, with newString: String) -> String {

        guard !oldString.isEmpty, !newString.isEmpty else { return self }

        let charArray = Array(self.characters)
        let oldCharArray = Array(oldString.characters)
        let newCharArray = Array(newString.characters)

        var matchedChars = 0
        var resultCharArray = [Character]()

        for char in charArray {
            if char == oldCharArray[matchedChars] {
                matchedChars += 1
                if matchedChars == oldCharArray.count {
                    resultCharArray.append(contentsOf: newCharArray)
                    matchedChars = 0
                }
            } else {
                for i in 0 ..< matchedChars {
                    resultCharArray.append(oldCharArray[i])
                }
                if char == oldCharArray[0] {
                    matchedChars = 1
                } else {
                    matchedChars = 0
                    resultCharArray.append(char)
                }
            }
        }

        return String(resultCharArray)

    }
}

示例用法:

let myString = "Hello World HelHelloello Hello HellHellooo"
print(myString.replacing("Hello", with: "Hi"))

输出:

Hi World HelHiello Hi HellHioo

---

使用Foundation的方法:

您可以在 String 结构上使用 replacingOccurrences 方法。

let myString = "Hello World"
let newString = myString.replacingOccurrences(of: "World", with: "Everyone")
print(newString) // prints "Hello Everyone"