iphone - NSPredicate 仅过滤日期字段的 "year"部分

Question

我有一个带有日期字段的实体，我想选择给定年份的记录。如何为工作构建 NSPredicate？在 Core Data 中没有找到任何关于日期函数(如果有的话)

谢谢

Answer 1

最终我或多或少按照 Wienke 的建议做了。要创建获取特定年份记录的谓词，我是这样做的:

- (NSPredicate*) predicateFromYear:(NSInteger)start span:(NSInteger)aSpan {
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *dc = [NSDateComponents new];

[dc setYear:start];

NSDate *startDate,*endDate;

startDate = [cal dateFromComponents:dc];
[dc setYear:aSpan];
endDate = [cal
           dateByAddingComponents:dc
           toDate:startDate
           options:0];

[dc release];
return [NSPredicate predicateWithFormat:
        @"date >= CAST(%f, \"NSDate\") AND date < CAST(%f, \"NSDate\")",
        [startDate timeIntervalSinceReferenceDate],
        [endDate timeIntervalSinceReferenceDate]];  }