Displaying text based on what day it is - swift

Question

I'm trying to display the time of something being open based on what day it is. Something like this:
Opening Hours
**Monday: 8:00-17:00**
Tuesday: 8:00-17:00
Wednesday: 8:00-17:00
Thursday: 8:00-17:00
Friday: 8:00-17:00
Saturday: 8:00-13:00
Sunday: closed
Or simply display
Monday: 8:00-17:00
My assumption would be to use switch statements, but what would I need to do to find out what day it is?

Answer 1

Another solution could be:
import Foundation
let today = NSDate()
let dateFormatter = NSDateFormatter()
let currentDay = NSCalendar.currentCalendar().component(.Weekday, fromDate:today);
dateFormatter.dateFormat = "EEEE"
let dayOfWeekString = dateFormatter.stringFromDate(today)
switch currentDay
{
case 2,3,4,5:
print("\(dayOfWeekString): 8:00 - 17:00")
case 6:
print("\(dayOfWeekString): 8:00 - 13:00")
default:
print("\(dayOfWeekString): closed")
}

Answer 2

You can use component(_:fromDate:) to get the week day from the current date. That would look like:
let currentDay = NSCalendar.currentCalendar().component(.Weekday, fromDate:NSDate());
Based on the value you get for currentDay, you can provide the correct opening hours.

Answer 3

You can make use of NSCalendar to get the .Weekday unit as an integer (Sunday through Saturday as 1 ... 7 for the Gregorian calendar).
Given you know the day of the week represented as an Int, rather than using a switch statement, you could use a [Int: String] dictionary for the different opening hours.
let calendar = NSCalendar.currentCalendar()
let today = calendar.component(.Weekday, fromDate: NSDate())
// Gregorian calendar: sunday = 0, monday = 1, ...
let openingHours: [Int: String] = [1: "Sunday: closed", 2: "Monday: 8:00-17:00", 3: "Tuesday: 8:00-17:00"] // ...
print("Opening hours:\n\(openingHours[today] ?? "")")
/* Opening hours:
Monday: 8:00-17:00 */
Another alternative is to create a computed property extension to NSDate() that returns the current weekday as a String
extension NSDate {
var weekday : String {
let formatter = NSDateFormatter()
formatter.dateFormat = "EEEE"
return formatter.stringFromDate(self)
}
}
This can be readily used with a [String: String] dictionary for holding the set of weekday : opening hours:
/* example usage */
let openingHours: [String: String] =
["Sunday": "closed",
"Monday": "8:00-17:00",
"Tuesday": "8:00-17:00"] // ...
let today = NSDate().weekday
print("Opening hours:\n\(today): \(openingHours[today] ?? "")")
/* Opening hours:
Monday: 8:00-17:00 */

Answer 4

Rather than going with switch statements I would prefer a more generic solution. This is also a nice demonstration of leveraging tuples and type aliases for enhancing code expressiveness and readability.
typealias Time = (start: Int, end: Int)
// starting with Sunday
let openTimes: [Time] = [(0,0), (9,17), (9,17), (9,17), (9,17), (9,17), (9,12)]
let flags : NSCalendarUnit = [.Hour, .Weekday]
func isOpenAtTime(date: NSDate) -> Bool {
let time = NSCalendar.currentCalendar().components(flags, fromDate: date)
let openingHours = openTimes[time.weekday - 1]
let hour = time.hour
return hour >= openingHours.start && hour <= openingHours.end
}
You might want to handle a few edge cases as well, but you get the idea.
You could make this work with more granular time by using minutes instead of hours.