Learning Exercise
A DateTime in F# is an immutable object that contains both date and time information. DateTime instances are manipulated by calling their methods. Once a DateTime has been constructed, its value can never change. Any methods/functions that appear to modify a DateTime will actually return a new DateTime.
The textual representation of dates and times is dependent on the culture. Consider a DateTime with its date set to March 28 2019 and its time set to 14:30:59. Converting this DateTime to a string when using the en-US culture (American English) returns "3/28/19 2:30:59 PM". When using the fr-BE culture (Belgian French), the same code returns a different value: "28/03/19 14:30:59".
Understanding which DateTime methods are culture-dependent is important to know. In general, any DateTime method that deals with strings (either as input or output) will be dependent on the current culture.
In this exercise you'll be working on an appointment scheduler for a beauty salon in New York that opened on September 15th in 2012.
You have four tasks, which will all involve appointment dates. The dates and times will use one of the following three formats:
"7/25/2019 13:45:00""July 25, 2019 13:45:00""Thursday, July 25, 2019 13:45:00:00"The tests will automatically set the culture to en-US - you don't have to set or specify the culture yourselves.
Implement the schedule function that can parse a textual representation of an appointment date into the corresponding DateTime format:
schedule "7/25/2019 13:45:00"
// => DateTime(2019, 7, 25, 13, 45, 0)
Implement the hasPassed function that takes an appointment date and checks if the appointment was somewhere in the past:
hasPassed (DateTime(1999, 12, 31, 9, 0, 0))
// => true
Implement the isAfternoonAppointment function that takes an appointment date and checks if the appointment is in the afternoon (>= 12:00 and < 18:00):
isAfternoonAppointment (DateTime(2019, 03, 29, 15, 0, 0))
// => true
Implement the description function that takes an appointment date and returns a description of that date and time:
description (DateTime(2019, 03, 29, 15, 0, 0))
// => "You have an appointment on 3/29/2019 3:00:00 PM."
Implement the anniversaryDate function that returns this year's anniversary date, which is September 15th:
anniversaryDate()
// => DateTime(2019, 9, 15, 0, 0, 0)
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