介绍三种方法获取 Date (NSDate) 的年月日。
用 date 表示当前日期。测试日期为公历 2017 年 2 月 5 日，农历丁酉年，鸡年，正月初九。
let date: Date = Date()
NSDate *date = [NSDate date];
获取公历年月日
用 Calendar (NSCalendar) 获取公历年月日
let calendar: Calendar = Calendar(identifier: .gregorian)
print("Year:", calendar.component(.year, from: date))
print("Month:", calendar.component(.month, from: date))
print("Day:", calendar.component(.day, from: date))
NSCalendar *calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
NSLog(@"Year: %ld", [calendar component:NSCalendarUnitYear fromDate:date]);
NSLog(@"Month: %ld", [calendar component:NSCalendarUnitMonth fromDate:date]);
NSLog(@"Day: %ld", [calendar component:NSCalendarUnitDay fromDate:date]);
结果
用 Calendar 和 DateComponents (NSCalendar 和 NSDateComponents) 获取公历年月日
let componentSet: Set<Calendar.Component> = Set(arrayLiteral: .year, .month, .day)
let components: DateComponents = calendar.dateComponents(componentSet, from: date)
print("Year:", components.year!)
print("Month:", components.month!)
print("Day:", components.day!)
NSCalendarUnit calenderUnit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
NSDateComponents *components = [calendar components:calenderUnit fromDate:date];
NSLog(@"Year: %ld", components.year);
NSLog(@"Month: %ld", components.month);
NSLog(@"Day: %ld", components.day);
结果
用 DateFormatter (NSDateFormatter) 获取公历年月日
let formatter: DateFormatter = DateFormatter()
print("Date formatter identifier:", formatter.calendar.identifier) // gregorian by default
formatter.dateFormat = "y"
print("Year:", formatter.string(from: date))
formatter.dateFormat = "M"
print("Month:", formatter.string(from: date))
formatter.dateFormat = "d"
print("Day:", formatter.string(from: date))
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
NSLog(@"Date formatter calendar: %@", formatter.calendar.calendarIdentifier); // gregorian by default
formatter.dateFormat = @"y";
NSLog(@"Year: %@", [formatter stringFromDate:date]);
formatter.dateFormat = @"M";
NSLog(@"Month: %@", [formatter stringFromDate:date]);
formatter.dateFormat = @"d";
NSLog(@"Day: %@", [formatter stringFromDate:date]);
