我想将一个很长的字符串从一个单词切成另一个单词。我想获得这些词之间的子字符串。 为此,我使用以下字符串扩展名:
extension String {
func slice(from: String, to: String) -> String? {
guard let rangeFrom = range(of: from)?.upperBound else { return nil }
guard let rangeTo = self[rangeFrom...].range(of: to)?.lowerBound else { return nil }
return String(self[rangeFrom..<rangeTo])
}
这确实很好,但是我的原始字符串包含一些“从”到“到”单词,并且我需要这两个单词之间的每个子字符串,但是通过扩展,我只能得到第一个子字符串
示例:
let raw = "id:244476end36475677id:383848448end334566777788id:55678900end543"
我想从这个原始字符串示例中获取以下子字符串:
sub1 = "244476"
sub2 = "383848448"
sub3 = "55678900"
如果我打电话:
var text = raw.slice(from: "id:" , to: "end")
我只第一次出现(text =“ 244476”)
感谢您的阅读。每个答案都很好。
PS:通过在stackoverflow中编写代码段,我总是会出错。
答案 0 :(得分:1)
我不是尝试从头到尾解析字符串,而是使用现有方法的组合将其转换为所需的结果。这是我的处理方式:
import Foundation
let raw = "id:244476end36475677id:383848448end334566777788id:55678900end543"
let result = raw
.components(separatedBy: "id:")
.filter{ !$0.isEmpty }
.map { segment -> String in
let slices = segment.components(separatedBy: "end")
return slices.first! // Removes the `end` and everything thereafter
}
print(result) // => ["244476", "383848448", "55678900"]
答案 1 :(得分:1)
您可以使用while循环获取子字符串的范围,以重复从该点到字符串结尾的搜索,并使用map从结果范围中获取子字符串:
extension StringProtocol {
func ranges<S:StringProtocol,T:StringProtocol>(between start: S, and end: T, options: String.CompareOptions = []) -> [Range<Index>] {
var ranges: [Range<Index>] = []
var startIndex = self.startIndex
while startIndex < endIndex,
let lower = self[startIndex...].range(of: start, options: options)?.upperBound,
let range = self[lower...].range(of: end, options: options) {
let upper = range.lowerBound
ranges.append(lower..<upper)
startIndex = range.upperBound
}
return ranges
}
func substrings<S:StringProtocol,T:StringProtocol>(between start: S, and end: T, options: String.CompareOptions = []) -> [SubSequence] {
ranges(between: start, and: end, options: options).map{self[$0]}
}
}
游乐场测试:
let string = """
your text
id:244476end
id:383848448end
id:55678900end
the end
"""
let substrings = string.substrings(between: "id:", and: "end") // ["244476", "383848448", "55678900"]