使用 NSPredicate 使用 2D-NSDictionaries 过滤 NSArray

Question

我有一个 NSArray ，其中包含一些 NSDictionaries ，它们本身也包含一个 NSDictionary 。

NSDictionary *dict1 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"cover" forKey:@"type"] forKey:@"image"];
NSDictionary *dict2 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"cover" forKey:@"type"] forKey:@"image"];
NSDictionary *dict3 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"back" forKey:@"type"] forKey:@"image"];
NSDictionary *dict4 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"cover" forKey:@"type"] forKey:@"image"];

NSArray *myArray = [NSArray arrayWithObjects:dict1, dict2, dict3, dict4, nil];

有没有一种方法可以使用 NSPredicate 过滤类型为 fe“cover”的所有图像字典的 myArray ？

尝试过类似

predicateWithFormat:@"(SELF.image.type == %@)", @"cover"]

or 的

predicateWithFormat:@"(image.type == %@)", @"cover"]

谓词，但没有成功。

提前致谢！如果有不清楚的地方请发表评论

//编辑

以便

NSPredicate *p = [NSPredicate predicateWithFormat:@"image.type == %@", @"cover"];

正常工作。但就我而言，我想整理出大小==原始。我所做的是，

NSPredicate *p = [NSPredicate predicateWithFormat:@"image.size == %@", @"original"];

但随后我的应用程序崩溃

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSSymbolicExpression length]: unrecognized selector sent to instance

并指向我的 filteredArrayUsingPredicate 方法。我看不出类型和大小之间有任何区别。在这里查看我的数组的 NSLog

 (
        {
        image =         {
            height = 1500;
            id = 4e5808765e73d607350059b4;
            size = original;
            type = poster;
            url = "someurl";
            width = 1000;
        };
    },
        {
        image =         {
            height = 750;
            id = 4e5808765e73d607350059b4;
            size = mid;
            type = poster;
            url = "someurl";
            width = 500;
        };
    },

有人知道为什么当我尝试使用 size 而不是 type 时它会崩溃吗？

Answer 1

SIZE 是保留关键字。

位于 谓词编程指南：

保留以下单词：

AND、OR、IN、NOT、ALL、ANY、SOME、NONE、 LIKE、不区分大小写、CI、匹配、包含、BEGINSWITH、ENDSWITH、BETWEEN、NULL、NIL、SELF、TRUE、YES、FALSE、NO、FIRST、LAST、SIZE、ANYKEY、SUBQUERY、CAST、TRUEPREDICATE、FALSEPREDICATE

Answer 2

以下代码对我有用：

NSDictionary *dict1 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"cover" forKey:@"type"] forKey:@"image"];
NSDictionary *dict2 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"cover" forKey:@"type"] forKey:@"image"];
NSDictionary *dict3 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"back" forKey:@"type"] forKey:@"image"];
NSDictionary *dict4 = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:@"cover" forKey:@"type"] forKey:@"image"];

NSArray *myArray = [NSArray arrayWithObjects:dict1, dict2, dict3, dict4, nil];

NSPredicate *p = [NSPredicate predicateWithFormat:@"image.type == %@", @"cover"];
NSLog(@"%@", [myArray filteredArrayUsingPredicate:p]);