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我将如何使用（理想情况下）带有键值编码集合运算符的单个谓词来简化这一点？（最后感兴趣的数组是filteredGames。）

NSManagedObjectContext *context;
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:[NSEntityDescription entityForName:@"Game" inManagedObjectContext:context];
NSArray *games = [context executeFetchRequest:request error:nil];

NSMutableArray *filteredGames = [[NSMutableArray alloc] init];
for (Game *game in games) {
    NSInteger maxRoundNumber = [game.rounds valueForKeyPath:@"@max.number"];
    Round *maxRound = [[game.rounds filteredSetUsingPredicate:[NSPredicate predicateWithFormat:@"number = %d", maxRoundNumber]] anyObject];
    if (maxRound.someBoolProperty)
        [filteredGames addObject:game];
}

游戏有 的NSSet属性rounds，Rounds并且Round有 的NSInteger属性number，我正在寻找那些Games最高数Round有一些BOOL属性的人someBoolProperty。

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1 回答 1

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这似乎做你想做的事：

NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Game"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"ANY SUBQUERY(rounds, $r, $r.someBoolProperty = YES).number = @max.rounds.number"];
于 2013-01-06T17:46:50.070 回答