iphone - 使用NSPredicate删除对象

Question

我有备受追捧的字典，里面有很多小词典。
如何使用isChanged = 1从父词典中删除NSPredicate的对象？

{
    "0_496447097042228" =     {
        cellHeight = 437;
        isChanged = 1;
    };
    "100000019882803_193629104095337" =     {
        cellHeight = 145;
        isChanged = 0;
    };
    "100002140902243_561833243831980" =     {
        cellHeight = 114;
        isChanged = 1;
    };
    "100004324964792_129813607172804" =     {
        cellHeight = 112;
        isChanged = 0;
    };
    "100004324964792_129818217172343" =     {
        cellHeight = 127;
        isChanged = 0;
    };
    "100004324964792_129835247170640" =     {
        cellHeight = 127;
        isChanged = 1;
    };
}

Answer 1

作为使用NSPredicate的简单替代方法，可以使用NSDictionary内置的keysOfEntriesPassingTest:。此答案假定“isChanged”是NSString，值0或1是NSNumber:

NSSet *theSet = [dict keysOfEntriesPassingTest:^(id key, id obj, BOOL *stop) {
    return [obj[@"isChanged"] isEqualToNumber: @1];
}];

返回的集合是通过测试的键的列表。从那里，您可以删除所有与以下内容匹配的内容:
[dict removeObjectsForKeys:[theSet allObjects]];