[英]Sort array with 2 sort descriptors
我有一个NSDictionary
对象数组,每个对象都有一个EventDate
和SecurityLevel
。 我想先按日期然后按安全级别对它们进行排序。 我怎样才能做到这一点?
Obj1: SecurityLevel: 5, Date: 20/05/2015 22:03
Obj2: SecurityLevel: 5, Date: 05/03/2015 05:28
Obj3: SecurityLevel: 4, Date: 14/04/2015 11:01
Obj4: SecurityLevel: 4, Date: 07/08/2015 09:31
Obj6: SecurityLevel: 3, Date: 24/04/2015 21:06
Obj5: SecurityLevel: 3, Date: 29/01/2016 22:38
Obj7: SecurityLevel: 2, Date: 02/06/2015 20:49
Obj8: SecurityLevel: 2, Date: 13/07/2015 17:46
Obj9: SecurityLevel: 1, Date: 19/08/2015 07:57
他们应该这样排序:
Obj1: SecurityLevel: 5, Date: 20/05/2015 22:03
Obj2: SecurityLevel: 5, Date: 05/03/2015 05:28
Obj4: SecurityLevel: 4, Date: 07/08/2015 09:31
Obj3: SecurityLevel: 4, Date: 14/04/2015 11:01
Obj5: SecurityLevel: 3, Date: 29/01/2016 22:38
Obj6: SecurityLevel: 3, Date: 24/04/2015 21:06
Obj8: SecurityLevel: 2, Date: 13/07/2015 17:46
Obj7: SecurityLevel: 2, Date: 02/06/2015 20:49
Obj9: SecurityLevel: 1, Date: 19/08/2015 07:57
我做了类似的事情,但它没有按预期工作:
- (NSArray*)sortEventsByDateAndSecurity:(NSArray*)toSort
{
NSSortDescriptor *securityDescriptor = [[NSSortDescriptor alloc] initWithKey:@"SeverityLevel" ascending:NO];
NSArray *sortDescriptors = @[securityDescriptor];
NSArray *sortedSecurity = [toSort sortedArrayUsingDescriptors:sortDescriptors];
NSArray *reverseOrderUsingComparator = [sortedSecurity sortedArrayUsingComparator:^(id obj1, id obj2) {
NSDictionary *dictObject1 = (NSDictionary*)obj1;
NSDictionary *dictObject2 = (NSDictionary*)obj2;
NSDate *obj1Date = [Utils stringToDate:[dictObject1 valueForKey:@"EventDate"] format:@"dd/MM/yyyy HH:mm"];
NSDate *obj2Date = [Utils stringToDate:[dictObject2 valueForKey:@"EventDate"] format:@"dd/MM/yyyy HH:mm"];
return [obj1Date compare:obj2Date];
}];
return reverseOrderUsingComparator;
}
您应该简单地调用sortedArrayUsingDescriptors:
使用 2 个描述符而不是 1 个描述符的数组:
- (NSArray*)sortEventsByDateAndSecurity:(NSArray*)toSort
{
NSSortDescriptor *securityDescriptor = [[NSSortDescriptor alloc] initWithKey:@"SeverityLevel" ascending:NO];
NSSortDescriptor *eventDateDescriptor = [[NSSortDescriptor alloc] initWithKey:@"EventDate" ascending:NO comparator:^NSComparisonResult(NSString *obj1, NSString *obj2) {
NSDate *obj1Date = [Utils stringToDate:obj1 format:@"dd/MM/yyyy HH:mm"];
NSDate *obj2Date = [Utils stringToDate:obj2 format:@"dd/MM/yyyy HH:mm"];
return [obj1Date compare:obj2Date];
}];
NSArray *sortDescriptors = @[securityDescriptor, eventDateDescriptor];
return [toSort sortedArrayUsingDescriptors:sortDescriptors];
}
在这种情况下,第二个排序描述符将仅应用于与第一个排序描述符相同的对象。 对于您的情况,这意味着具有相同SecurityLevel
对象将按EventDate
排序。
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