我有一个这样的字符串：
0x829bd824b016326a401d083b33d092293333a830
我想保留前 6 个字符并保留最后 4 个：
0x829b...a830
我该怎么做？我在 Apple 文档中看到了 .firstIndex(of: "-") 选项，但这将用于删除特定字符，因此它不适用。
截断字符串的中间并替换它 - Swift
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问答
hpsheng 回答：截断字符串的中间并替换它 - Swift
您可以使用 drop 的一种方式，如下所示：
let stringTest: String = "0x829bd824b016326a401d083b33d092293333a830"
print(stringTest.replacingOccurrences(of: stringTest.dropFirst(6).dropLast(4),with: "..."))
// It will print: 0x829b...a830
这里扩展名：
extension String {
func replacingRange(indexFromStart: Int,indexFromEnd: Int,replacing: String = "") -> Self {
return self.replacingOccurrences(of: self.dropFirst(indexFromStart).dropLast(indexFromEnd),with: replacing)
}
func replacingRange2(indexFromStart: Int,replacing: String = "") -> Self {
return String(self.prefix(indexFromStart)) + replacing + String(self.suffix(indexFromEnd))
}
}
用例：
print(stringTest.replacingRange(indexFromStart: 6,indexFromEnd: 4,replacing: "..."))
来自 Leo Dabus 的 Master 扩展：
extension StringProtocol where Self: RangeReplaceableCollection {
func replacing<S: StringProtocol>(indexFromStart: Int,with string: S = "") -> Self {
Self.init(replacingOccurrences(of: dropFirst(indexFromStart).dropLast(indexFromEnd),with: string))
}
func replacing2<S: StringProtocol>(indexFromStart: Int,with string: S = "") -> Self {
Self.init(self.prefix(indexFromStart) + Self(string) + self.suffix(indexFromEnd))
}
func replacing3<S: StringProtocol>(indexFromStart: Int,with string: S = "") -> Self {
Self.init(self.prefix(indexFromStart) + string[...] + self.suffix(indexFromEnd))
}
}