I'm trying to figure out how to calculate store opening times based on the way they are normally expressed. For example: Monday - Friday, 9am - 6pm. I want to know two things from this criteria. Is the store open? If it is how long will it be before it closes?
My confusion with the documentation is that NSDate calculations expect unique date data sets to perform calculations not generic as expressed above. For example NSDate expects 2010-07-12T09:00:00Z & 2010-07-12T18:00:00Z to form the start basis of the calculation and like wise for the days in between.
Do I need to create a data set for the year on this basis to calculate the results? Or is there a clever way I can get NSCalendar / NSDateComponents to do all this hard work for me?
There is no simple/automatic way. You have to parse the string yourself, form two, let's say startDate and endDate (or something alike). From them you can extract the day of the week and time (that's where NSCalendar and NSDateComponents come in handy).
Related
Is there a concept of working-days in the Nodatime library?
What I would like to do is to somehow state that there is 5 working-days in a calender week, and then be able to ask something like:
From [any given date] + 10 working-days what is the end date?
or
From [this calender date] to [that calender date] how many working-days are in that interval?
No, this doesn't exist as you described it. However, you can certainly use Noda Time's LocalDate object and implement your own logic. An O(n) implementation would simply use LocalDate.DayOfWeek and a for loop. I'm sure one could create an O(1) implementation easily as well.
I used
[currentComps setFirstWeekday:2];
It returns the number of the day of week starting with Sunday. How should I hardcode returning this number starting with Monday?
Contrary to the comment by Martin R, you can use NSCalendar to specify the first day of the week via:
- (void)setFirstWeekday:(NSUInteger)weekday
Reading the documentation of NSCalendar, it states the method setFirstWeekday:
Sets the index of the first weekday for the receiver.
I haven't tried this myself, but I would assume that creating an instance of NSCalendar, calling the aforementioned method and also calling setCalendar: on your NSDateComponents would attenuate all dates components returned to work as you intend.
I have design an application in which i am have three text field in which i am giving my time like as 10:10 PM. Now problem is that i want to calculate time difference between current time and entered time. How calculate time?
Depending what you mean by "entered time" you will most likely need to look at NSDateFormatter and parse the entered time into a usable form, then get a date using NSDate (i.e. NSDate * now = [NSDate date];) and do whatever math you need using the methods available in `NSDate'.
If you are just determining the difference between entered date and now this method would suit you:
- (NSTimeInterval)timeIntervalSinceNow
you can get the difference in seconds using time intervals (e.g. that of the NSDate and CFAbsoluteTimeGetCurrent).
I am using Objective-C within X-code.
I am iterating through a dictionary which contains a date value as one of it's keys. All I want to do is get an array of all the distinct dates so I can use them in a table, as headers. I just plan on
iterating the dictionary and adding dates to a mutable array each time I encounter a new date.
I must set previous date to new date for comparisons to work and I am having a very difficult time figuring out how to set one date equal to another date.
This seems like it should be such a simple thing to do and I am trying to avoid converting the dates to strings first - but if that's what I have to do, then so be it.
Any help would be appreciated.
Thanks,
Gerry O.
If you know the time offset is same as GMT, you could do it by dividing the date's timestamp by 86400 seconds (or three more 0s in milliseconds) and comparing those. If a time offset is there, add or subtract by 3600 seconds per hour before you divide them. But then again, leap years and seconds would break that...
Most languages have libraries support extracting the year, date, month, etc. They take everything into account, usually.
In Objc, you can get a NSDateComponents from NSCalendar's components:fromDate: method. After this, you can call the components to see exactly what each component (I suggest year, month, day) is.
I think you want code to compare dates and You need two loops nested.... where in outer loops iterates with conditional inner loop... In inner loop you just check that previously you had the same date or not...
please go through the below post on same site...
How to compare two dates in Objective-C
hope you will get solution... else clarify your question....
I would like to make a function that input a NSDate and output the last date of the month. Do you guys know how to do it in Cocoa?
It's the day before the first day of the next month. Add a month, set the day to 1, subtract a day. For setting the day to 1, you'll find it easier to go via NSCalendar. See here for details.
If you're doing date computations, you should always use NSCalendar and related classes, because that's the only way to be forward-compatible with changes to calendars, support for non-"standard" calendars, and so on.
Read the Date and Time Programming Guide section on Calendrical Calculations to get an idea of how these classes work together.