ios - 如何提高一个月计算中工作日数的准确性？

Question

我正在尝试计算一周中的每一天在一个月中有多少天。我使用下面的这个问题/答案作为我想要实现的目标的基础，并且它在大多数情况下都有效。

how can we get the number of sundays on an given month ? ( swift )

不幸的是，如果是工作日，它还会计算下个月的第一天。

我对代码的计算方式不够熟悉，无法理解是否可以在任何地方添加 -1 或其他内容到该月的总天数。

如果有人可以推荐解决方案，我们将不胜感激。

我已经尝试将“numberOfSundays += 1”更改为“numberOfSundays += 0”，因为我认为这可能会导致问题。

func getNumberOfDaysInMonth (month : Int, Year : Int, nameOfDay: String) -> Int? {

    var dateComponents = DateComponents()
    dateComponents.year = Year
    dateComponents.month = month

    let calendar = NSCalendar.current
    let date = calendar.date(from: dateComponents)

    guard let range = calendar.range(of: .day, in: .month, for: date!) else { return nil }

    let numDays = range.endIndex

    // New code starts here:

    var numberOfSundays = 0

    let dateFormatter = DateFormatter()

    for day in 1...numDays {

        dateComponents.day = day

        guard let date = calendar.date(from: dateComponents) else { return nil }

        dateFormatter.dateFormat = "EEEE"
        let dayOfWeek = dateFormatter.string(from: date) // Get day of week

        if dayOfWeek == nameOfDay { // Check if it's a Monday
            numberOfSundays += 1
        }
    }

    return numberOfSundays
}

---

getNumberOfDaysInMonth(month: 06, Year: 2019, nameOfDay: "Monday")

getNumberOfDaysInMonth(month: 06, Year: 2019, nameOfDay: "Tuesday")

getNumberOfDaysInMonth(month: 06, Year: 2019, nameOfDay: "Wednesday")

getNumberOfDaysInMonth(month: 06, Year: 2019, nameOfDay: "Thursday")

getNumberOfDaysInMonth(month: 06, Year: 2019, nameOfDay: "Friday")

在我调用函数“getNumberOfDaysInMonth(month: 06, Year: 2019, nameOfDay: "Monday")”的地方，它返回 5 作为 2019 年 6 月的天数，实际上有 4。

Answer 1

func getNumberOfDaysInMonth(month: Int , year: Int, nameOfDay: String) -> Int? {

    var components = DateComponents()
    components.year = year
    components.month = month

    let calendar = Calendar.current

    guard let date = calendar.date(from: components),
        let range = calendar.range(of: .day, in: .month, for: date) else { return nil }

    return range
        .map { DateComponents(year: year, month: month, day: $0) }
        .map { calendar.date(from: $0) }
        .compactMap { date  -> String? in
            guard let date = date else { return nil }
            let dateFormatter = DateFormatter()
            dateFormatter.dateFormat = "EEEE"
            return dateFormatter.string(from: date)
        }
        .filter { $0 == nameOfDay }
        .count
}