Summary of iOS time and date

1. Get timestamp

• Unit: second, reserved six significant digits in the following format:1574068247.545103

NSDate *datenow = [NSDate date];
NSString *timeSp = [NSString stringWithFormat:@"%f", (double)[datenow timeIntervalSince1970]];
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• Unit: second integer in the following format:1574068265

NSDate *datenow = [NSDate date];
NSString *timeSp = [NSString stringWithFormat:@"%ld", (long)[datenow timeIntervalSince1970]];
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• Unit: millisecond, integer, imprecise, followed by three0, the format is as follows:1574068602000

NSDate *datenow = [NSDate date];
NSString *timeSp = [NSString stringWithFormat:@"%ld", (long)[datenow timeIntervalSince1970]*1000];
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• Unit: millisecond, integer, exact, format:1574070082387

/ / get the current time 0 seconds time NSDate * date = [NSDate dateWithTimeIntervalSinceNow: 0]; // * NSTimeInterval Time = [Date timeIntervalSince1970]*1000; NSString *timeStr = [NSString stringWithFormat:@"%.0f", time];
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2. Timestamp to date

// The timestamp passed in is /1000 NSTimeInterval timeInterval = [timeStr doubleValue]/1000; NSDate *detailDate = [NSDate dateWithTimeIntervalSince1970:timeInterval]; NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; // Instantiate an NSDateFormatter object and set the time format. Here you can set the format as you wantsetDateFormat:@"yyyy-MM-dd HH:mm:ss SS"];
NSString *dateStr = [dateFormatter stringFromDate:detailDate];
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3. Comparison of two dates

/ / 1. To convert the two timestamp to date NSDate * date1 = [NSDate dateWithTimeIntervalSince1970:1451047216]. NSDate *date2 = [NSDate dateWithTimeIntervalSince1970:1451847216]; NSDate *date3 = [date1 :date2]; // Start // if date1 is written earlier than date2 -- > Otherwise, NSDate *date3 = [date1 :date2]; NSLog(@"Earlier date: %@",date3); NSDate *date4 = [date1 laterDate:date2]; NSLog(@"Late date: %@",date4); BOOL type BOOL result = [date1 isEqualToDate:date2]; NSLog(@"%d",result);
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• Can solve cross-year, cross-month, flat leap year time processing problems

/ / 100 days NSDate * date = [NSDate dateWithTimeIntervalSinceNow: 24 * 60 * 60 * 100]. NSDate *nowDate = [NSDate date]; // The date is in ascending orderif ([nowDate compare:date] == NSOrderedAscending) {
    NSLog(@Now =2019-11-18, ndate=2020-02-26);
}
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4. The calendar componentNSCalendar

NSDate *nowDate = [NSDate date]; NSCalendar *calendar = [NSCalendar currentCalendar]; // Initialize the calendar component, You can select the component you want NSDateComponents *comps = [Calendar components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay|NSCalendarUnitWeekday|NSCalendarUnitWeekdayOrdinal|N SCalendarUnitWeekOfMonth|NSCalendarUnitWeekOfYear|NSCalendarUnitYearForWeekOfYear fromDate:nowDate]; Return the index of the day of the week (1 = Sunday, 2 = Monday,... , 7 = Saturday) NSInteger weekDay = [comps weekDay]; NSInteger day = [comps day]; NSInteger weekOfYear = [comps weekOfYear];Copy the code

5. commonNSDateFormatterThe following formats can be useddateFormatterSymbols are formatted separately to get the required data for processing

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