按属性IN数组过滤Core数据结果 [英] Filter Core Data results by property IN array

问题描述

我目前有Core Data成功返回标题为 Event 的特定实体的所有结果：

I currently have Core Data successfully returning all of the results for a specific entity titled Event:

NSManagedObjectContext *context = [delegate managedObjectContext];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Event" 
                                                     inManagedObjectContext:context];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDescription];

NSError *error;
NSArray *fetchResults = [context executeFetchRequest:request error:&error];

Event实体的一个属性是标题为 tid 。我也有一个数组 filterArray 包含所有允许的tid值。

One property of the Event entity is a string titled tid. I also have an array filterArray that contains all allowed tid values.

如何获取我的Core Data请求只返回具有与 filterArray 中的值之一匹配的tid属性的事件？我相信答案与NSPredicate有关，但是我还不够熟悉它，它不能让它弯曲我的意志。

How can I get my Core Data request to only return events that have a tid property that matches one of the values in filterArray? I believe the answer relates to NSPredicate but I am not familiar enough with it yet to get it to bend to my will.

推荐答案

尝试此操作：

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"tid IN %@", filterArray];

[request setPredicate:predicate];

请查看聚合操作中的谓词编程指南。

编辑

请查看 NSPredicate iPhone 3.2 SDK核心数据IN子句NSInvalidArgumentException异常。这是同样的错误，你有。问题是列/属性名称中有一个拼写错误。语法应该没问题，它不能只找到 tid 。

Have a look at NSPredicate iPhone 3.2 SDK Core Data "IN clause" NSInvalidArgumentException exception. It's same error you have. The problem was a typo in the column/attribute name. The syntax should be alright, it can't just find tid.

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