Question

我有一个具有NSDate属性的Core Data模型。我想白天过滤数据库。我假设解决方案将涉及NSPredicate，但我不确定如何将它们放在一起。

我知道如何使用NSDate和NSDateComponents比较两个NSCalendar的日期，但如何使用NSPredicate对其进行过滤？

也许我需要在NSManagedObject子类上创建一个类别，该类别可以返回仅有年，月和日的裸日期。然后我可以在NSPredicate中进行比较。这是你的推荐，还是有更简单的东西？

Answer 1

给定NSDate * startDate 和 endDate 以及NSManagedObjectContext * moc ：

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(date >= %@) AND (date <= %@)", startDate, endDate];
NSFetchRequest *request = [[[NSFetchRequest alloc] init] autorelease];
[request setEntity:[NSEntityDescription entityForName:@"EntityName" inManagedObjectContext:moc]];
[request setPredicate:predicate];

NSError *error = nil;
NSArray *results = [moc executeFetchRequest:request error:&error];

Answer 2

如何将startDate和endDate设置为上面给出的答案的示例：

...

NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth ) fromDate:[NSDate date]];
//create a date with these components
NSDate *startDate = [calendar dateFromComponents:components];
[components setMonth:1];
[components setDay:0]; //reset the other components
[components setYear:0]; //reset the other components
NSDate *endDate = [calendar dateByAddingComponents:components toDate:startDate options:0];
predicate = [NSPredicate predicateWithFormat:@"((date >= %@) AND (date < %@)) || (date = nil)",startDate,endDate];

...

我在这里搜索一个月内的所有条目。值得一提的是，这个例子还展示了如何搜索'nil'date-entires。

Answer 3

在Swift中我得到了类似的东西：

        let dateFormatter = NSDateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd"
        let date = dateFormatter.dateFromString(predicate)
        let calendar = NSCalendar(calendarIdentifier: NSGregorianCalendar)
        let components = calendar!.components(
            NSCalendarUnit.CalendarUnitYear |
                NSCalendarUnit.CalendarUnitMonth |
                NSCalendarUnit.CalendarUnitDay |
                NSCalendarUnit.CalendarUnitHour |
                NSCalendarUnit.CalendarUnitMinute |
                NSCalendarUnit.CalendarUnitSecond, fromDate: date!)
        components.hour = 00
        components.minute = 00
        components.second = 00
        let startDate = calendar!.dateFromComponents(components)
        components.hour = 23
        components.minute = 59
        components.second = 59
        let endDate = calendar!.dateFromComponents(components)
        predicate = NSPredicate(format: "day >= %@ AND day =< %@", argumentArray: [startDate!, endDate!])

我很难发现字符串插值"\(this notation)"不能用于比较NSPredicate中的日期。

Answer 4

我将Glauco Neves的答案移植到Swift 2.0并将其包装在一个接收日期的函数中，并返回相应日期的(20000)：

NSPredicate

Answer 5

日期的Swift 3.0扩展名：

extension Date{

func makeDayPredicate() -> NSPredicate {
    let calendar = Calendar.current
    var components = calendar.dateComponents([.year, .month, .day, .hour, .minute, .second], from: self)
    components.hour = 00
    components.minute = 00
    components.second = 00
    let startDate = calendar.date(from: components)
    components.hour = 23
    components.minute = 59
    components.second = 59
    let endDate = calendar.date(from: components)
    return NSPredicate(format: "day >= %@ AND day =< %@", argumentArray: [startDate!, endDate!])
}
}

然后使用：

 let fetchReq = NSFetchRequest(entityName: "MyObject")
 fetchReq.predicate = myDate.makeDayPredicate()

Answer 6

添加Rafael的答案（非常有用，谢谢！），移植到Swift 3.

func predicateForDayFromDate(date: Date) -> NSPredicate {
    let calendar = Calendar(identifier: Calendar.Identifier.gregorian)
    var components = calendar.dateComponents([.year, .month, .day, .hour, .minute, .second], from: date)
    components.hour = 00
    components.minute = 00
    components.second = 00
    let startDate = calendar.date(from: components)
    components.hour = 23
    components.minute = 59
    components.second = 59
    let endDate = calendar.date(from: components)

    return NSPredicate(format: "YOUR_DATE_FIELD >= %@ AND YOUR_DATE_FIELD =< %@", argumentArray: [startDate!, endDate!])
}

Answer 7

我最近花了一些时间尝试解决同样的问题，并将以下内容添加到准备开始日期和结束日期的备选项列表中（包括iOS 8及更高版本的更新方法）......

NSDate *dateDay = nil;
NSDate *dateDayStart = nil;
NSDate *dateDayNext = nil;

dateDay = <<USER_INPUT>>;

dateDayStart = [[NSCalendar currentCalendar] startOfDayForDate:dateDay];

//  dateDayNext EITHER
dateDayNext = [dateDayStart dateByAddingTimeInterval:(24 * 60 * 60)];

//  dateDayNext OR
NSDateComponents *dateComponentDay = nil;
dateComponentDay = [[NSDateComponents alloc] init];
[dateComponentDay setDay:1];
dateDayNext = [[NSCalendar currentCalendar] dateByAddingComponents:dateComponentDay
                                                            toDate:dateDayStart
                                                           options:NSCalendarMatchNextTime];

...以及核心数据NSPredicate的{{1}}（如上文其他答案所示）......

NSFetchRequest

Answer 8

对我而言，这是有效的。

NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit ) fromDate:[NSDate date]];
    //create a date with these components
    NSDate *startDate = [calendar dateFromComponents:components];
    [components setMonth:0];
    [components setDay:0]; //reset the other components
    [components setYear:0]; //reset the other components
    NSDate *endDate = [calendar dateByAddingComponents:components toDate:startDate options:0];

    startDate = [NSDate date];
    endDate = [startDate dateByAddingTimeInterval:-(7 * 24 * 60 * 60)];//change here

    NSString *startTimeStamp = [[NSNumber numberWithInt:floor([endDate timeIntervalSince1970])] stringValue];
    NSString *endTimeStamp = [[NSNumber numberWithInt:floor([startDate timeIntervalSince1970])] stringValue];


   NSPredicate *predicate = [NSPredicate predicateWithFormat:@"((paidDate1 >= %@) AND (paidDate1 < %@))",startTimeStamp,endTimeStamp];
    NSLog(@"predicate is %@",predicate);
    totalArr = [completeArray filteredArrayUsingPredicate:predicate];
    [self filterAndPopulateDataBasedonIndex];
    [self.tableviewObj reloadData];
    NSLog(@"result is %@",totalArr);

我已将当前日期的数组过滤回7天。我的意思是我从当前日期获得一周的数据。这应该工作。

注意：我将以毫秒为单位的日期转换为1000，并在之后进行比较。如果您需要任何清晰度，请告诉我。

Answer 9

以先前的答案为基础，使用Swift 5.x进行更新和替代方法

func predicateForDayUsingDate(_ date: Date) -> NSPredicate {
    
    var calendar = Calendar.current
    calendar.timeZone = NSTimeZone.local
    // following creates exact midnight 12:00:00:000 AM of day
    let startOfDay = calendar.startOfDay(for: date)
    // following creates exact midnight 12:00:00:000 AM of next day
    let endOfDay = calendar.date(byAdding: .day, value: 1, to: startOfDay)!
    
    return NSPredicate(format: "day >= %@ AND day < %@", argumentArray: [startOfDay, endOfDay])
}

如果您希望将endOfDay的时间设置为晚上11:59:59，则可以添加...

    let endOfDayLessOneSecond = endOfDay.addingTimeInterval(TimeInterval(-1))

但是您可以将NSPredicate更改为...

    return NSPredicate(format: "day >= %@ AND day <= %@", argumentArray: [startOfDay, endOfDayLessOneSecond])

...特别说明从day < %@到day <= %@的变化。

NSPredicate：按NSDate属性的日期过滤对象

9 个答案: