如何创建一个or和and双语句

Question

有下面三个类型获取，需要添加一个AND语句过滤结果，其中mark是使用状态。

1.

NSMutableArray *questionNumberArray=[[NSMutableArray alloc] init];

// Fetch questions
NSManagedObjectContext *context = self.document.managedObjectContext;
NSFetchRequest *fetchRequest =
[[NSFetchRequest alloc] initWithEntityName:@"Questions"];

//building the predicate with selected category
NSMutableArray *parr = [NSMutableArray array];

if ([cat0str length]){
    [parr addObject:[NSPredicate predicateWithFormat:@"question.category CONTAINS[c] %@",cat0str]];
}
if ([cat1str length]){
    [parr addObject:[NSPredicate predicateWithFormat:@"question.category CONTAINS[c] %@",cat1str]];
}
if ([cat2str length]){
    [parr addObject:[NSPredicate predicateWithFormat:@"question.category CONTAINS[c] %@",cat2str]];
}

NSPredicate *compoundPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:parr];

[fetchRequest setPredicate:compoundPredicate];

2.

    NSPredicate *markPredicate =[NSPredicate predicateWithFormat:@"question.mark == 1"];
}

想要实现的是：

NSPredicate *finalPredicate = [compoundPredicate && markPredicate];

[fetchRequest setPredicate:finalPredicate];

Answer 1

这应该可以解决

NSPredicate *finalPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:
         [NSArray arrayWithObjects:compoundPredicate, markPredicate, nil]];

或者使用“modern Objective-C”语法

NSPredicate *finalPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:
                                     @[compoundPredicate, markPredicate]];