根据 NSString 值的匹配从 NSMutableDictionary 中删除条目

Question

在对 Instagram API 进行网络调用后，我返回了一个带有以下键/值结构的 responseDictionary NSDictionary 委托：

{
data =     (
            {
        bio = "Los Angeles/Orange County Realtor\U00ae \n\U6d1b\U6749\U77f6\U623f\U5730\U4ea7\U7ecf\U7eaa\U4eba\nCall/Text/WhatsApp: (310) 717-1321\nEmail: Jxxxcom\nWeChat (\U5fae\U4fe1): xx";
        "full_name" = "xx yy (\U7530\U4f73\U6dfc) Rx Realty";
        id = 25354408;
        "profile_picture" = "http://scontent-a.cdninstagram.com/hphotos-xpa1/outbound-distillery/t0.0-20/OBPTH/profiles/profile_xxx_75sq_1391378894.jpg";
        username = jxxi;
        website = "http://www.Jxghty.com";
    },

profile_picture 键通常有一个 NSString 值，其中包含anonymousUser（对于没有设置任何个人资料图片的用户）。

我希望从我的 responseDictionary 中删除这些条目，如下所示：

        //Create mutable copy of IG responseDictionary
        NSMutableDictionary *dictCleanAvatars = [responseDictionary mutableCopy];
        NSLog(@"Log dictCleanAvatars after mutableCopy IG response: %@", dictCleanAvatars);

        NSArray *keys = [dictCleanAvatars allKeys]; //get all the keys
        NSUInteger k2 = [dictCleanAvatars count];
        NSLog(@"k2 in dictCleanAvatars before cleanup is: %lu", (unsigned long)k2);

        for (int i = 0; i<k2; i++)
        {

            if ([[dictCleanAvatars objectForKey:[keys objectAtIndex:i]] isKindOfClass:[NSString class]])
            {
                //if its an NSString - don't want an exception if its another type of object
                NSLog(@"Yes, objectAtIndex:i us Kind ofClass NSString for i = %d", i);

                if ([[dictCleanAvatars objectForKey:[keys objectAtIndex:i]] rangeOfString:@"anonymousUser"].location != NSNotFound)
                {
                    NSLog(@"Yes, anonymousUser identified in objectAtIndex:i for i = %d", i);
                    //if object has the key word im looking for
                    [dictCleanAvatars removeObjectForKey:[keys objectAtIndex:i]]; //remove the key
                    NSLog(@"That's dictCleanAvatars after loop %d: %@", i, dictCleanAvatars);
                }
            }
        }

但这不起作用。

会重视更多经验丰富的 iOS 开发者的反馈。

Answer 1

如果您尝试构建一个包含 data 键数组中的所有内容的数组，但忽略 profile_picture 包含字符串“AnonymousUser”的那些字典，您可以使用 NSPredicate：

NSArray *dataArray = responseDictionary[@"data"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"not (profile_picture contains 'AnonymousUser')"];
NSArray *filteredArray = [dataArray filteredArrayUsingPredicate:predicate];

或者你可以使用predicateWithBlock:

NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(NSDictionary *evaluatedObject, NSDictionary *bindings) {
    return [evaluatedObject[@"profile_picture"] rangeOfString:@"AnonymousUser"].location == NSNotFound;
}];

顺便说一句，如果您已经有一个可变数组，您还可以使用filterUsingPredicate 从中删除条目，使用上述谓词：

NSMutableArray *mutableDataArray = [responseDictionary[@"data"] mutableCopy];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"not (profile_picture contains 'AnonymousUser')"];
[mutableDataArray filterUsingPredicate:predicate];

---

另一方面，如果您不想从字典数组中删除整个字典，而是想简单地删除出现“AnonymousUser”的profile_picture，则需要确保不仅数组是可变的，它的组成字典也是可变的。

最简单的方法是在解析 JSON 时指定 NSJSONReadingMutableContainers 选项。然后，您可以遍历 NSMutableDictionary 条目，删除带有 profile_picture 和“AnonymousUser”的 profile_picture 条目：

NSMutableDictionary *responseDictionary = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableContainers error:&error];
NSMutableArray *mutableDataArray = responseDictionary[@"data"];

for (NSMutableDictionary *dictionary in mutableDataArray) {
    NSString *profilePicture = dictionary[@"profile_picture"];
    if ([profilePicture rangeOfString:@"AnonymousUser"].location != NSNotFound) {
        [dictionary removeObjectForKey:@"profile_picture"];
    }
}

但是，如果您在解析 JSON 时无法指定 NSJSONReadingMutableContainers 选项并且卡在不可变集合中，则需要制作它的可变副本。不幸的是，数组的简单 mutableCopy 不会使成员字典本身可变，但您可以使用 Core Foundation 对 CFPropertyListCreateDeepCopy 的调用来创建具有可变条目的可变数组，然后您可以对其进行修改：

NSMutableArray *mutableDataArray = CFBridgingRelease(CFPropertyListCreateDeepCopy(kCFAllocatorDefault, (CFArrayRef)responseDictionary[@"data"], kCFPropertyListMutableContainers));

然后你可以使用上面的for循环，遍历这个数组的字典条目，删除有问题的profile_picture条目。

Answer 2

if [[dictCleanAvatars objectForKey:[keys objectAtIndex:i]] isEqualToString@"anonymousUser"] {

问题是，假设 [dictCleanAvatars objectForKey:[keys objectAtIndex:i]] 不是 NSString？您可能需要先检查一下。

Answer 3

如果您正在查看的唯一字段是 profile_picture，我会采用一种不太通用的方法，这种方法更具可读性和可理解性

此代码适用于我

- (void)testExample
{
    NSDictionary *dictionary = @{ @"data": @[ @{ @"bio": @"blah blah", @"profile_picture": @"some stuff anonymousUser other stuff" },
                                              @{ @"bio": @"some other object", @"profile_picture": @"some other profile picture link" }] };
    // dictionary is a mock of the data you provided

    NSArray *data = [dictionary objectForKey:@"data"];
    for (NSDictionary * avatarDict in data) {
        NSMutableDictionary *mdict = [avatarDict mutableCopy];
        id ppid = [mdict objectForKey:@"profile_picture"];
        if ([ppid isKindOfClass:[NSString class]]) {
            NSString *pp = (NSString *)ppid;
            if ([pp rangeOfString:@"anonymousUser"].location != NSNotFound) {
                [mdict removeObjectForKey:@"profile_picture"];
            }
        }
        NSLog(@"altered dictionary: %@", mdict);
    }
}

输出：

2014-08-13 10:53:36.727 test[11981:60b] altered dictionary: {
    bio = "blah blah";
}
2014-08-13 10:53:36.728 test[11981:60b] altered dictionary: {
    bio = "some other object";
    "profile_picture" = "some other profile picture link";
}