1.利用keyValue的方式 (@distinctUnionOfObjects.self)
NSMutableArray *studentIDArray = [NSMutableArray array];
studentIDArray = [studentIDArray valueForKeyPath:@"@distinctUnionOfObjects.self"];
1.利用keyValue的方式 (@distinctUnionOfObjects.self)
NSMutableArray *studentIDArray = [NSMutableArray array];
studentIDArray = [studentIDArray valueForKeyPath:@"@distinctUnionOfObjects.self"];