Days Between Days

App Development
1

Hello, I’m trying to calculate days between dates, and I thought it was just ‘1’ off for some of them, but maybe it takes time into account?

I just want days so, tomorrow is “1” day away. Yesterday is -1 days away, today is 0 days away.

but, it seems today =1 and tomorrow =1 in this thing. any ideas? thanks

let startDate = Date()
let eventDateRaw = 2021-11-16 05:00:00 +0000)
       
let dayDiffs = Calendar.current.dateComponents([.day], from: startDate, to: eventDateRaw!)

PRINT OUTPUT
Optional(“Today 2021”)
Optional(2021-11-16 05:00:00 +0000)
1
Optional(“Today + 1”)
Optional(2021-11-17 05:00:00 +0000)
1

Both values return “1”.

I don’t even want to store the time, but it looks like it makes you. I don’t enter it, something is picking 5:00 AM for me, which is my only guess as to why it’s not working how I’d like.

days that are not today, seem to work fine.

thanks for any help!

2

Maybe it’s not time, well, kinda.

Looks like Date() for me is 2021-11-16 16:22:00 +0000

but, it’s 11:22 AM here. so -5 time zone. maybe the issue is that. But I’d like the app to work in any timezone, since really I just want the date.

maybe strip the time from Date() before feeding it to the dayDiff line?

I’ll play with it and see what happens :slight_smile:

3

Please post all of the relevant code when asking for help. What is eventDateRaw?

This works for me:

let startDate = Date()
let endDate = Calendar.current.date(byAdding: .day, value: -1, to: startDate)!
let daysDiff = Calendar.current.dateComponents([.day], from: startDate, to: endDate)
print(daysDiff.day!)
//returns -1
1 Like
4

Sorry, still new to this.

It’s part of a loop I have for displaying the data in a table.

2021-11-16 05:00:00 +0000)

and

2021-11-17 05:00:00 +0000)

for both values, it returns “1” (in my app)

for the 11/16/2021 I’d expect it to return “0”

When I try it playground, I currently get: Can’t assign value of type string to date, I assume because I don’t have the format correct.

thanks again


import UIKit

let startDate = Date()
// var endDate = Date()

endDate = "2021-11-16 16:22:00 +0000"  // I know this is string, but not sure how to format for date. Thanks


let dayDiffs = Calendar.current.dateComponents([.day], from: startDate, to: endDate)

print(startDate)
print(endDate)
print(dayDiffs)

Currently I’m prompting for a date with a text field, which I want to replace with a datepicker. I just don’t know how to do that yet, as I’ve only been doing this for a few weeks.

Maybe if I did that first I wouldn’t have to hassle with dates vs. strings.

Should have time to play with datepicker tomorrow.

5

What output do you get for this code:

let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "yyyy-MM-dd HH:mm:ssZ"


extension Date {
    var startOfDay: Date {
        Calendar.current.startOfDay(for: self)
    }
}

let startDate = Date().startOfDay
let endDate = formatter.date(from: "2021-11-16 16:22:00 +0000")!.startOfDay

let dayDiffs = Calendar.current.dateComponents([.day], from: startDate, to: endDate)

print(startDate)
print(endDate)
print(dayDiffs)
1 Like
6

2021-11-16 05:00:00 +0000
2021-11-16 05:00:00 +0000
day: 0 isLeapMonth: false

thanks. I’ll play around with this and see what happens. Thank you much.

if I understand correctly, you’re forcing ‘start of day’. Which should fix the time issues.

This is so fun, I sat with my laptop for almost 3 hours yesterday before realizing the time.

I was able to get this in my original code, and was also able to remove a bunch of lines that no longer applied. thanks again!

I didn’t force end of day on the 2nd date, if it’s stored with only that value when created, it shouldn’t be needed, but then I remember to assume all input is hostile.

7

You might want to check out this set of documents:

I’m still reading it, but it looks like you can learn anything you ever wanted to know about dates and times.

1 Like