Swift 5：如何根据提供的字符串计算出正确的日期？

Question

我不擅长Swift所以我想知道如何计算当前时间在两次之间

我从后端收到以下响应。 {"workHours":"M-F 9:00 - 18:00"}

如何使用正则表达式和 DateFormatter 从 "M-F 11:00 - 20:00" 响应中获取 start(9:00) 时间、end(18:00) 时间？（我不确定是从这种字符串中获取Date对象的正确方法，如果不是请推荐最好的方法和经验）

Answer 1

您可以使用以下正则表达式：

"^\w-\w\s{1}(\d{1,2}:\d{2})\s{1}-\s{1}(\d{1,2}:\d{2})$"

崩溃

^ asserts position at start of a line
A-Z a single character in the range between A (index 65) and Z (index 90) (case sensitive)
- matches the character - literally (case sensitive)
A-Z a single character in the range between A (index 65) and Z (index 90) (case sensitive)
\s matches any whitespace character (equal to [\r\n\t\f\v]) {1} Quantifier — Matches exactly one time meaningless quantifier)
1st Capturing Group (\d{1,2}:\d{2})
\d{1,2} matches a digit (equal to [0-9])
{1,2} Quantifier — Matches between 1 and 2 times, as many times as possible, giving back as needed (greedy)
: matches the character : literally (case sensitive)
\d{2} matches a digit (equal to [0-9])
\s matches any whitespace character (equal to [\r\n\t\f\v]) {1} Quantifier — Matches exactly one time (meaningless quantifier)
- matches the character - literally (case sensitive)
\s{1} matches any whitespace character (equal to [\r\n\t\f\v ]) {1} Quantifier — Matches exactly one time (meaningless quantifier)
2nd Capturing Group (\d{1,2}:\d{2})
$ asserts position at the end of a line

let response = "M-F 11:00 - 20:00"
let pattern = "^[A-Z]-[A-Z]\s{1}(\d{1,2}:\d{2})\s{1}-\s{1}(\d{1,2}:\d{2})$"
let regex = try! NSRegularExpression(pattern: pattern)
if let match = regex.matches(in: response, range: .init(response.startIndex..., in: response)).first,
    match.numberOfRanges == 3 {
    match.numberOfRanges
    let start = match.range(at: 1)
    print(response[Range(start, in: response)!])
    let end = match.range(at: 2)
    print(response[Range(end, in: response)!])
}

这将打印

11:00
20:00

获取开始时间和结束时间之间的时间差（这认为生成的字符串将匹配上述正则表达式：

extension StringProtocol {
    var minutesFromTime: Int {
        let index = firstIndex(of: ":")!
        return Int(self[..<index])! * 60 + Int(self[index...].dropFirst())!
    }
}

let start = response[Range(match.range(at: 1), in: response)!]
let end = response[Range(match.range(at:2), in: response)!]
let minutes = end.minutesFromTime - start.minutesFromTime // 540
let hours = Double(minutes) / 60  // 9

Swift 5：如何根据提供的字符串计算出正确的日期？

Swift 5: How to calculate correct Date from provided string?

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calculation