I would like to work out the difference in months
at the moment I have this code:
dateInterval = [endDate timeIntervalSinceDate:startDate];
But that returns a value in seconds, I would like to see the difference between the dates in months.
How would I do this?
Thanks
NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init];
[inputFormatter setDateFormat:#"dd/MM/yyyy"];
NSDate *startDate = [inputFormatter dateFromString:#"07/03/2011"];
NSDate *endDate = [inputFormatter dateFromString:#"07/06/2011"];
NSInteger month_delta = [[[NSCalendar currentCalendar] components: NSMonthCalendarUnit fromDate: startDate toDate: endDate options: 0] month];
NSLog(#"---------------------------->>%d", month_delta);
[inputFormatter release]; // <-- in case not using ARC
it will log:
---------------------------->>3
You can create a NSDateComponents from the NSDates in question and just subtract the total months. (Total months = 12*year+currentMonth)
http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSDateComponents_Class/Reference/Reference.html#//apple_ref/occ/cl/NSDateComponents
Related
I'm using the following code to convert a user-supplied birthdate to its equivalent years from the current date. The output is always off by an inconsistent amount in years and very large numbers in days and months.
NSDateFormatter *tempFormatter = [[NSDateFormatter alloc] init];
[tempFormatter setDateFormat:#"yyyy-mm-dd hh:mm:ss"];
NSDate *birthDate = [tempFormatter dateFromString:[NSString stringWithFormat:#"%#-%#-%# 01:00:00",self.birthYear.text,self.birthMonth.text,self.birthDay.text]];
NSDate* now = [NSDate date];
NSDateComponents* ageComponents = [[NSCalendar currentCalendar]
components:NSYearCalendarUnit
fromDate:birthDate
toDate:now
options:0];
NSInteger years = [ageComponents year];
NSInteger days = [ageComponents day];
NSInteger months = [ageComponents month];
NSLog(#"Years: %ld, Days: %ld, Months: %ld",years,days, months);
What gets outputted when I input "06-16-1986" is the following
Years: 28, Days: 9223372036854775807, Months: 9223372036854775807
The year is off by 1 and the months and days are producing extremely large numbers. I get the same issue using various dates. For example, "12-07-1989" produces
Years: 25, Days: 9223372036854775807, Months: 9223372036854775807
What am I doing wrong here?
the problem is in this line
NSDateComponents* ageComponents = [[NSCalendar currentCalendar]
components:NSYearCalendarUnit
fromDate:birthDate
toDate:now
options:0];
if you want month & days to be calculated you need to include that in the components like this
NSDateComponents* ageComponents = [[NSCalendar currentCalendar]
components:( NSYearCalendarUnit | NSDayCalendarUnit | NSMonthCalendarUnit)
fromDate:birthDate
toDate:now
options:0];
also your format is wrong for month string
[tempFormatter setDateFormat:#"yyyy-mm-dd hh:mm:ss"];
should be corrected as
[tempFormatter setDateFormat:#"yyyy-MM-dd hh:mm:ss"];
now you will get correct date.
explanation.
as mentioned on apple documentation these are 1-based. so incase you dont provide a value it will put 1 as default. so earlier your month format was "mm" and it was not correctly setting a month for the birthday hence it was 1986-01-16 so now its 2014-04-01 (in singapore). So you get 28 years which is correct.
Add |NSMonthCalendarUnit|NSDayCalendarUnit to your components, change the date format from yyyy-mm-dd hh:mm:ss to yyyy-MM-dd hh:mm:ss:
NSDateFormatter *tempFormatter = [[NSDateFormatter alloc] init];
[tempFormatter setDateFormat:#"yyyy-MM-dd hh:mm:ss"];
NSDate *birthDate = [tempFormatter dateFromString:[NSString stringWithFormat:#"%#-%#-%# 01:00:00",#"2000", #"04",#"01"]];
NSDate* now = [NSDate date];
NSDateComponents* ageComponents = [[NSCalendar currentCalendar]
components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit
fromDate:birthDate
toDate:now
options:0];
NSInteger years = [ageComponents year];
NSInteger days = [ageComponents day];
NSInteger months = [ageComponents month];
NSLog(#"Years: %d, Days: %d, Months: %d",years,days, months);
I have a very interesting problem: When calculating the number of days between two dates, my calculator gives the wrong results for the month of March only. I have two text fields, one for each date. If I enter 3/7/12 in date1, and 3/13/12 in date2, the result is 7, which is correct (I am counting the first day as well). But when I enter date1 = 3/7/12 and date2 = 3/14/12, the result is still 7, but it should be 8. Likewise, if I enter date1 = 3/7/12 and date2 = 3/23/12, the result should be 17, but it is 16. If I change the month to April so that date1 = 4/7/12 and date2 = 4/23/12, the result is 17. Every month is working as intended, only the month of March is giving me wrong results. Does anyone have any idea what I am missing? Is this a timezone problem? How do I fix it? Here is my code:
NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
[dateFormatter1 setDateFormat:#"MM/dd/yyyy"];
NSDate *startdate1 = [dateFormatter1 dateFromString: date1.text];
NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc] init];
[dateFormatter2 setDateFormat:#"MM/dd/yyyy"];
NSDate *enddate2 = [dateFormatter2 dateFromString: date2.text];
int start1 = [startdate1 timeIntervalSince1970];
int end2 = [enddate2 timeIntervalSince1970];
double difference12 = end2-start1;
int days12;
days12 =(int)((double)difference12/(3600.0*24.00)+1);
result12.text = [[NSString alloc] initWithFormat:#"%i", days12]
If you use NSCalendar, you won't need to deal with Daylight Savings Time calculation.
int days = [[[NSCalendar currentCalendar] components:NSDayCalendarUnit
fromDate:startDate1
toDate:endDate2
options:0] day] + 1;
Most like this is a daylight savings issue (March 11th, 2012). Set the date formatters' timezones to:
[NSTimeZone timeZoneForSecondsFromGMT:0];
This should fix the issue.
To add to others, please do not rely on number of seconds in a day being 86400 all the time, it won't. Be sure to watch Session 211 Performing Calendar Calculations from WWDC 2011.
You can think of NSDate as a point in time. If you want to calculate number of days between two dates, this is a calendar issue and there are more than one calendars (like the Mayan calendar).
What you need is NSDateComponents:
NSDate *dateToday = [NSDate date];
NSDateComponents *dateBComponent = [[NSDateComponents alloc] init];
[dateBComponent setDay:-10];
NSDate *date10DaysAgo = [[NSCalendar currentCalendar] dateByAddingComponents:dateBComponent
toDate:dateToday
options:0];
NSCalendar *calendar = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDateComponents *components = [calendar components:NSDayCalendarUnit
fromDate:date10DaysAgo
toDate:dateToday
options:0];
NSLog(#"Difference: %d", components.day);
I found the codes to calculate days difference between two dates here.
I write a method :
-(NSInteger)daysWithinEraFromDate:(NSDate *) startDate toDate:(NSDate *) endDate
{
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSInteger startDay=[gregorian ordinalityOfUnit:NSDayCalendarUnit
inUnit: NSEraCalendarUnit forDate:startDate];
NSInteger endDay=[gregorian ordinalityOfUnit:NSDayCalendarUnit
inUnit: NSEraCalendarUnit forDate:endDate];
return endDay-startDay;
}
This method has a problem: it can't consider the timezone thing. Even I add a line like this:
[gregorian setTimeZone:[NSTimeZone localTimeZone]];
My test code is like this:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSString *strDate = #"2012-09-03 23:00:00";
NSDate *dateStart = [dateFormat dateFromString:strDate];
strDate = #"2012-09-04 01:00:00";
NSDate *dateEnd = [dateFormat dateFromString:strDate];
NSLog(#"Days difference between %# and %# is: %d days",[dateFormat stringFromDate:dateStart],[dateFormat stringFromDate:dateEnd],[self daysWithinEraFromDate:dateStart toDate:dateEnd]);
The result is:
Days difference between 2012-09-03 23:00:00 and 2012-09-04 01:00:00 is: 0 days
I want to get 1 day as result by the number of midnights between the two dates. My timezone is GMT +8. But this calculation is based on GMT, so I get the wrong days number. Is there anyway to solve this problem? Thank you.
Scott Lemmon's method can solve my problem. I rewrite my code like this:
-(NSInteger)daysWithinEraFromDate:(NSDate *) startDate toDate:(NSDate *) endDate
{
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setTimeZone:[NSTimeZone localTimeZone]];
NSDate *newDate1 = [startDate dateByAddingTimeInterval:[[NSTimeZone localTimeZone] secondsFromGMT]];
NSDate *newDate2 = [endDate dateByAddingTimeInterval:[[NSTimeZone localTimeZone] secondsFromGMT]];
NSInteger startDay=[gregorian ordinalityOfUnit:NSDayCalendarUnit
inUnit: NSEraCalendarUnit forDate:newDate1];
NSInteger endDay=[gregorian ordinalityOfUnit:NSDayCalendarUnit
inUnit: NSEraCalendarUnit forDate:newDate2];
return endDay-startDay;
}
If the time zone offset isn't working, how about just add or subtract it manually instead?
In your case NSDate *newDate = [oldDate dateByAddingTimeInterval:(-8 * 60 * 60)]; to subtract off your +8 hours.
Or if you want to find the GMT offset automatically as well then it would simply be NSDate *newDate = [oldDate dateByAddingTimeInterval:(-[[NSTimeZone localTimeZone] secondsFromGMT])
Another thought:
A perhaps easier solution would be to just disregard the time information altogether. Just set it to the same arbitrary number for both dates, then as long as the dates come from the same timezone you will always get the correct number of mid-nights between them, regardless of GMT offset.
What you really want is the NSDate method timeIntervalSinceDate:, and take that result and if it's more than 0 but less than 86400 (the number of seconds in a day), that's one day. Otherwise, divide your result by 86400 and you'll get the number of days.
The way you currently have your code, there's only 2 hours between the two days and that's why you are seeing a result of 0 and not one.
Edit - and to determine if midnight has happened, let's try this function I just wrote off the top of my head:
- (NSDate *) getMidnightDateFromDate: (NSDate *) originalDate
{
NSDateComponents *components = [[NSCalendar currentCalendar] components:NSIntegerMax fromDate:originalDate];
[components setHour:0];
[components setMinute:0];
[components setSecond:0];
NSDate *midnight = [[NSCalendar currentCalendar] dateFromComponents:components];
return(midnight);
}
- (BOOL) howManyDaysDifferenceBetween: startDate and: endDate
{
NSDate * firstMidnight = [self getMidnightDateFromDate: startDate];
NSDate * secondMidnight = [self getMidnightDateFromDate: endDate];
NSTimeInterval timeBetween = [firstMidnight timeIntervalSinceDate: secondMidnight];
NSInteger numberOfDays = (timeBetween / 86400);
return(numberOfDays);
}
which I'm basing off Dave Delong's answer to this question. No guarantees that my code will work (I didn't test it), but I think the concept is sound.
I want to compare two NSDates with NOW ([NSDate date]).
NSDate *date1 = [NSDate dateWithString:#"1982-02-12 07:00:00 +0100"];
NSDate *now = [NSDate dateWithString:#"2012-01-25 10:19:00 +0100"]; //example
NSDate *date2 = [NSDate dateWithString:#"1989-02-12 15:00:00 +0100"];
I would like to check if now is between date1 and date2. In the example above this is the case. The date component should be completely ignored, so only the time component should be compared. How could I accomplish this?
Thanks in advance!
unsigned int flags = NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
NSCalendar* calendar = [NSCalendar currentCalendar];
NSDateComponents* components = [calendar components:flags fromDate:date1];
NSDate* timeOnly = [calendar dateFromComponents:components];
This will give you a date object where everything but the hours/minutes/seconds have been reset to some common value. Then you can use the standard NSDate compare functions on them.
For reference, here is the opposite question to yours: Comparing two NSDates and ignoring the time component
You can create a date representing the start of today and add the time as components to it to get the boundary dates.
NSDate *now = [NSDate date];
NSDate *startOfToday;
[[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit startDate:&startOfToday interval:NULL forDate:now];
NSDateComponents *startComps = [[NSDateComponents alloc] init];
startComps.hour = 7;
startComps.minute = 30;
NSDateComponents *endComps = [[NSDateComponents alloc] init];
endComps.hour = 20;
NSDate *startDate = [[NSCalendar currentCalendar] dateByAddingComponents:startComps toDate:startOfToday options:0];
NSDate *endDate = [[NSCalendar currentCalendar] dateByAddingComponents:endComps toDate:startOfToday options:0];
if ([startDate timeIntervalSince1970] < [now timeIntervalSince1970] && [now timeIntervalSince1970] < [endDate timeIntervalSince1970]) {
NSLog(#"good");
}
NSDateFormatter* formatterDate = [[[NSDateFormatter alloc] init] autorelease];
formatterDate.dateStyle = NSDateFormatterMediumStyle; // whatever format you like
NSDate *first_Date = [formatterDate dateFromString:#""];
NSDate *second_Date = [formatterDate dateFromString:#""];
NSDate *todaysDate = [NSDate date];
NSTimeInterval timeIntFormFirstDate = [todaysDate timeIntervalSinceDate:First_Date];
NSTimeInterval timeIntFronLastDate = [second_Date timeIntervalSinceDate:todaysDate];
int interval1 = timeIntFormFirstDate/60;
int interval2 = timeIntFronLastDate/60;
if (interval1 >0 && interval2 >0)
{
NSLog(#"Today's date is between first and second date");
}
I want to set the NSDate time with my desired hours:minutes:seconds
currently im working with NSDate component but it is not giving the desired result
[comps setHour: -hours];
[comps setMinute:0];
[comps setSecond:0];
NSDate *minDate = [calendar_c dateFromComponents:comps];
This works great as an NSDate category.
/** Returns a new NSDate object with the time set to the indicated hour,
* minute, and second.
* #param hour The hour to use in the new date.
* #param minute The number of minutes to use in the new date.
* #param second The number of seconds to use in the new date.
*/
-(NSDate *) dateWithHour:(NSInteger)hour
minute:(NSInteger)minute
second:(NSInteger)second
{
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components: NSYearCalendarUnit|
NSMonthCalendarUnit|
NSDayCalendarUnit
fromDate:self];
[components setHour:hour];
[components setMinute:minute];
[components setSecond:second];
NSDate *newDate = [calendar dateFromComponents:components];
return newDate;
}
With the above category, if you have an existing date you want to change the time on, you do so like this:
NSDate *newDate = [someDate dateWithHour:10 minute:30 second:00];
If, however, you are trying to add or subtract hours from an existing date, a category method to do that is also straightforward:
/** Returns a new date with the given number of hours added or subtracted.
* #param hours The number of hours to add or subtract from the date.
*/
-(NSDate*)dateByAddingHours:(NSInteger)hours
{
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setHour:hours];
return [[NSCalendar currentCalendar]
dateByAddingComponents:components toDate:self options:0];
}
Your approach should work fine. I needed a solution for this type problem (setting the individual date components) and the following code works as expected for me. My situation: I wanted to create a date object that used the current date but had the time set to a value that was passed in as a string.
NSString *string = #"7:00";
NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"];
NSDateFormatter *timeOnlyFormatter = [[NSDateFormatter alloc] init];
[timeOnlyFormatter setLocale:locale];
[timeOnlyFormatter setDateFormat:#"h:mm"];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *today = [NSDate date];
NSDateComponents *todayComps = [calendar components:(NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit) fromDate:today];
NSDateComponents *comps = [calendar components:(NSHourCalendarUnit | NSMinuteCalendarUnit) fromDate:[timeOnlyFormatter dateFromString:string]];
comps.day = todayComps.day;
comps.month = todayComps.month;
comps.year = todayComps.year;
NSDate *date = [calendar dateFromComponents:comps];
[calendar release];
[timeOnlyFormatter release];
[locale release];
One thing to note is that you really have to pay attention to time zones when you are judging whether a time appears to be accurate. For example, in my app, when you stop at a breakpoint, you will see the time in GMT (so it looks different than the input time, which is in my local time), but when the time is actually displayed on screen in the app, it is being formatted to display in the local timezone. You may need to take this into consideration to determine whether the result is actually different from what you would expect.
If this does not help, can you elaborate on "not giving the desired result"? What result is it giving and how does that compare to what you expected?
is Swift2
extension NSDate {
func dateWithHour (hour: Int, minute:Int, second:Int) ->NSDate?{
let calendar = NSCalendar.currentCalendar(),
components = calendar.components([.Day,.Month,.Year], fromDate: self)
components.hour = hour;
components.minute = minute;
components.second = second;
return calendar.dateFromComponents(components)
}
}
You can set 0 to hour, min, and second.
NSDateFormatter *tFmt = [[NSDateFormatter alloc] init];
tFmt.dateFormat = #"yyyy-MM-dd";
NSString *strNowDate = [NSString stringWithFormat:#"%# 00:00:00",[tFmt stringFromDate:[NSDate date]]];
NSDate *nowDate = [NSDate dateWithString:strNowDate formatString:#"yyyy-MM-dd HH:mm:ss"];
Swift 5 solution (based on #dattk answer) for those who fear Deprecation warnings :)
func date(withHour hour: Int, withMinute minute: Int, withSeconds second: Int) -> Date? {
let now = Date()
let calendar = NSCalendar.current
var components = calendar.dateComponents([.day,.month,.year], from: now)
components.hour = hour
components.minute = minute
components.second = second
return calendar.date(from: components)
}
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *comps = [calendar components:(NSCalendarUnitHour | NSCalendarUnitMinute) fromDate:[NSDate date]];
comps.hour = 0;
comps.minute = 15;
NSDate *date = [calendar dateFromComponents:comps];
iOS 8