NSDate operations (comparison, creation, addition or subtraction of a certain period of time on the existing date), nsdatedate

NSDate operations (comparison, creation, addition or subtraction of a certain period of time on the existing date), nsdatedate

Current Creation Time

 

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1. NSDate * date = [NSDate date];

 

 

24 hours from now on

NSTimeInterval a_day = 24*60*60;

NSDate * tomorrow = [NSDate dateWithTimeIntervalSinceNow: a_day];

Create date based on existing date

 

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1. NSTimeInterval a_day = 24*60*60;
2. NSDate * date = [NSDate date];
3. NSDate * tomorrow = [date addTimeInterval: date];

 

Date comparison

 

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1. BOOL isEqual = [date is1_todate: tomorrow];
2. F (isEqual ){
3. NSLog (@ "equal ");

 

// Obtain the earlier date

 

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1. NSDate * earlier_date = [tomorrow earlierDate: date];
2. NSLog (@ "earlierDate = % @", earlierDate );

 

// Date later

 

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1. NSDate * laterDate = [tomorrow laterDate: date];
2. NSLog (@ "laterDate = % @", laterDate );

 

// The number of seconds between two dates

 

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1. NSTimeInterval secondsInterval = [date timeIntervalSinceDate: tomorrow];
2. NSLog (@ "secondsInterval = % lf", secondsInterval );

 

 

// Create a date using the NSCalendar class

 

 

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1. NSDateComponents * comps = [[NSDateComponentsalloc] init];
2. [Comps setMonth: 01];
3. [Comps setDay: 31];
4. [Comps setYear: 2013];
5. NSCalendar * calendar = [[NSCalendaralloc] initWithCalendarIdentifier: NSGregorianCalendar];
6. NSDate * date = [calendar dateFromComponents: comps];

 

// Obtain the date from the existing date

 

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1. Unsigned units = NSMonthCalendarUnit | NSDayCalendarUnit | NSYearCalendarUnit;
2. NSDateComponents * _ comps = [calendar components: units fromDate: date];
3. NSInteger month = [_ comps month];
4. NSInteger year = [_ comps year];
5. NSInteger day = [_ comps day];
6. // NSDateFormatter implements date output
7. NSDateFormatter * formatter = [[NSDateFormatteralloc] init];
8. [Formatter setDateStyle: NSDateFormatterFullStyle]; // the machine code is output directly.
9. // Or manually set the style [formatter setDateFormat: @ "yyyy-mm-dd"];
10. NSString * dateString = [formatter stringFromDate: date];
11. NSLog (@ "dateString = % @", dateString );
12. NSLog (@ "formater = % @", formatter );

 

// Obtain the date format object

 

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1. -(NSDateFormatter *) getDateFormatter {
2. If (dateFormatter = nil ){
3. DateFormatter = [[NSDateFormatter alloc] init];
4. [DateFormatter setDateStyle: NSDateFormatterMediumStyle];
5. [DateFormatter setTimeStyle: NSDateFormatterNoStyle];
6. }
7. Return dateFormatter;
8. }