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iOS

Posted by Stephen Becker
Stephen Becker
7,056 Points

From Date - Birthday = Age

Hey Guys,

I have been trying to figure out with Swift, how I can make a function that makes a NSDate() - Birthday = Age

Here is a example of my current code

//: Account Details

import UIKit

let date = NSDate()

struct AccountDetails {
    let firstName: String
    let lastName: String
    let birthday: String

func fullName () -> String {
        return firstName + " " + lastName

func age () - > Int {
   return date -  birthday

    }
    }

let johnSmith = AccountDetails(firstName: "John", lastName: "Smith", birthday: "February 3rd, 1989")

1 Answer

Hayden Pennington
Hayden Pennington
6,154 Points

There are several ways to approach a solution. I have two options, and hopefully you can use one!

Depending on how much supporting code you have, you could change the struct AccountDetails, to store the birthday as Int values. Then use my this solution:

    // Create an instance of NSCalender with currentCalender
    let calender = NSCalendar.currentCalendar()

    // Set the components to the birthday
    let dateComponents = NSDateComponents()
    dateComponents.day = 21
    dateComponents.month = 8
    dateComponents.year = 1980

    // Create an NSDate object from the birthday
    let birthday = calender.dateFromComponents(dateComponents)

    // Get today's date
    let today = NSDate()

    // Use the NSCalender method to get the difference (e.g today - birthday)
    let age = calender.components(NSCalendarUnit.CalendarUnitYear,
        fromDate: birthday!,
        toDate: today,
        options: nil).year // Be sure to put .year

If you would prefer to store the birthday as a String, you could create a parsing method that takes a String as a parameter and returns a tuple with the the Int values.

Or store a variant of the String and use the following solution:

   // This would be the var in AccountDetails
    let birthdayString = "1980-08-21"

    // Create a Formatter
    let dateFormatter = NSDateFormatter()

    // Set the dateFormat. Browse the documentation for variant formats
    dateFormatter.dateFormat = "yyyy'-'MM'-'dd"

    // Create an NSDate holding the birthday, with the dateFormatter.
    let birthday = dateFormatter.dateFromString(birthdayString)

    // Get today's date
    let today = NSDate()

    // Create an instance of NSCalender with currentCalender
    let calender = NSCalendar.currentCalendar()

    // Use the NSCalender method to get the difference (e.g today - birthday)
    let age = calender.components(NSCalendarUnit.CalendarUnitYear,
        fromDate: birthday!,
        toDate: today,
        options: nil).year // Be sure to put .year

It seems like there isn't a clean way of doing this (Coming from an inexperienced IOS developer).

Hope this helps!