ios - CompoundPredicate NSPredicate

Question

例如，我有三个NSPredicates。

NSPredicate *pred1 = [NSpredicate ...];
NSPredicate *pred2 = [NSpredicate ...];
NSPredicate *pred3 = [NSpredicate ...];

而且我从服务器字符串中知道了如何需要组合谓词。

例如

(1 OR 2 OR 3)
(1 OR 3) AND 2
3 OR (1 AND 2)

如何在正确的条件下并在给出括号的情况下合并三个谓词？

谢谢

Answer 1

您总是可以像这样创建嵌套的NSCompoundPredicate

NSPredicate *orPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:@[firstPredicate, secondPredicate]];
NSPredicate *andPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:@[thirdPredicate, fourthPredicate]];
NSPredicate *finalPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:@[orPredicate, andPredicate]];