Check the date is in certain period.

Oh, I found a way.

So , I shared it. (if self answer is not legal in this forum, plz delete this thread)

From swift3, we can just compare like if (B < C) { 　　... even if it is Date.

Thanks.

However, you have to be careful, because A and B also have a time that affects the comparison. The correctness of the comparison depends on where A, B and C come from, or how they are constructed.

Right. To illustrate this in concrete terms, the mapping from a set of Gregorian date components (like 1986/04/05) to an absolute point in time depends on the time zone, so you might find that C falls between A and B for some users but not others.

In my experience virtually every easily-stated date and time problem has an obvious answer that’s wrong (for a fun time, read Your Calendrical Fallacy Is…), and finding the right answer requires you to really nail down the specification of the problem.

stcocoa, if you can explain more about the context of this issue we should be able to offer you better advice.

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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

I mean Swift "Date" class.

Thanks for your advice. I will be careful about that.

Thanks, QuinceyMorris😁

With Foundation framework you can do it with very little code like this:

let dateInterval = DateInterval(start: startDate, end: endDate)
print("The interval contains the date:",  dateInterval.contains(testDate))

The most complicated work to make the above working was converting the dates from String to Date...

import Foundation
let dateFormatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.dateFormat = "YYYY/MM/dd"

    return formatter
} ()
if let startDate = dateFormatter.date(from: "1980/04/30"),
    let endDate = dateFormatter.date(from: "1988/04/03"),
    let testDate = dateFormatter.date(from: "1986/04/05") {
    let dateInterval = DateInterval(start: startDate, end: endDate)
    print("The interval contains the date:",  dateInterval.contains(testDate))
}

let formatter = DateFormatter() 
formatter.dateFormat = "YYYY/MM/dd"

Don’t do this. If you set a fixed-format date you have to set the locale to

en_US_POSIX

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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"