ios 判断日期

1.生日正则表达式

#pragma 正则匹配生日

+ (BOOL)checkBirthNumber:(NSString *) birthNumber

{

NSString *pattern = @"((19[\\d]{2})|(20[0-1][\\d]))((0[1-9])|(1[0-2]))((0[1-9])|([1-2]\\d)|(3[0-1]))";

NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];

BOOL isMatch = [pred evaluateWithObject:birthNumber];

return isMatch;

}

2.获取当前日期

NSDate *date = [NSDate date];

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

[formatter setDateStyle:NSDateFormatterMediumStyle];

[formatter setTimeStyle:NSDateFormatterShortStyle];

[formatter setDateFormat:@"YYYY-MM-dd hh:mm:ss"];

NSString *DateTime = [formatter stringFromDate:date];

NSLog(@"%@============年-月-日时：分：秒=====================",DateTime);

3.获取当前的时间戳

NSTimeInterval time = [[NSDate date] timeIntervalSince1970];

long long int date = (long long int)time;

NSString *timeSp = [NSString stringWithFormat:@"%lld",date];

4.根据当前日期计算前n个月或后n个月的日期

NSDate *date = [NSDate date];

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

[formatter setDateFormat:@"yyyy-MM"];

NSDateComponents *comps = [[NSDateComponents alloc] init];

[comps setMonth:1]; (下个月)

// [comps setMonth:-1];（上个月）

NSCalendar *calender = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDate *mDate = [calender dateByAddingComponents:comps toDate:date options:0];

NSString *dateTime = [formatter stringFromDate:mDate];

NSLog(@"locationStr:%@",_dateTime);

5. 根据日期判断是星期几

@第一种写法:

NSDateComponents *_comps = [[NSDateComponents alloc] init];

[_comps setDay:23];

[_comps setMonth:3];

[_comps setYear:2014];

NSCalendar *gregorian = [[NSCalendar alloc]

initWithCalendarIdentifier:NSGregorianCalendar];

NSDate *_date = [gregorian dateFromComponents:_comps];

NSDateComponents *weekdayComponents =

[gregorian components:NSWeekdayCalendarUnit fromDate:_date];

int _weekday = [weekdayComponents weekday];

NSLog(@"_weekday::%d",_weekday);

@第二种写法：

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *comps = [[NSDateComponents alloc] init];

NSInteger unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekdayCalendarUnit |

NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;

NSDate *now = [NSDate date];

// 话说在真机上需要设置区域，才能正确获取本地日期，天朝代码:zh_CN

calendar.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"];

comps = [calendar components:unitFlags fromDate:now];

6.计算2个日期相差天数

/**

* 计算2个日期相差天数

* startDate 起始日期

* endDate 截至日期

-(NSInteger)daysFromDate:(NSDate *)startDate toDate:(NSDate *)endDate {

NSDateFormatter *dateFormatter=[[NSDateFormatter alloc] init];

// 话说在真机上需要设置区域，才能正确获取本地日期，天朝代码:zh_CN

dateFormatter.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"];

[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

//得到相差秒数

NSTimeInterval time = [endDate timeIntervalSinceDate:startDate];

int days = ((int)time)/(3600*24);

int hours = ((int)time)%(3600*24)/3600;

int minute = ((int)time)%(3600*24)/3600/60;

if (days <= 0 && hours <= 0&&minute<= 0) {

NSLog(@"0天0小时0分钟");

return 0;

}

else {

NSLog(@"%@",[[NSString alloc] initWithFormat:@"%i天%i小时%i分钟",days,hours,minute]);

// 之所以要 + 1，是因为此处的days 计算的结果不包含当天和最后一天\

（如星期一和星期四，计算机算的结果就是2天（星期二和星期三），日常算，星期一——星期四相差3天，所以需要+1）\

对于时分没有进行计算可以忽略不计

return days + 1;

}

7.计算当前日期与指定日期做对比

第一步：先获取系统当前日期，即本节当中的第2个知识点

第二步：先查看指定日期的格式，如是：2018-01-01，即可直接比较，如是：2018-01-01-00，需转换为相同的日期格式，返回NSDate形式

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setDateFormat:@"dd-MM-yyyy-HHmmss"];

NSDate *date = [dateFormatter dateFromString:@"30-09-2016-000000"];

第三步：进行比较，如果没达到指定日期，返回-1，刚好是这一时间，返回0，否则返回1

- (int)compareOneDay:(NSDate *)oneDay withAnotherDay:(NSDate *)anotherDay

{

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setDateFormat:@"dd-MM-yyyy-HHmmss"];

NSString *oneDayStr = [dateFormatter stringFromDate:oneDay];

NSString *anotherDayStr = [dateFormatter stringFromDate:anotherDay];

NSDate *dateA = [dateFormatter dateFromString:oneDayStr];

NSDate *dateB = [dateFormatter dateFromString:anotherDayStr];

NSComparisonResult result = [dateA compare:dateB];

NSLog(@"date1 : %@, date2 : %@", oneDay, anotherDay);

if (result == NSOrderedDescending) {

NSLog(@"Date1 is in the future");

return 1;

}

else if (result == NSOrderedAscending){

NSLog(@"没有达到指定日期");

return -1;

}

NSLog(@"两时间相同");