递归地遍历未知结构的NSDictionary [英] Recursively traverse NSDictionary of unknown structure

问题描述

有没有人做过一个未知结构的NSDictionary的递归有序遍历？我想采取任何NSDictionary并按层次顺序处理每个级别。

Has anyone done a recursive ordered traversal of an NSDictionary of unknown structure? I'd like to take any NSDictionary and process each level in hierarchical order.

1）这些数据来自经验证的JSON。是否可以说，从一个框架（如SBJSON（JSON框架）创建的NSDictionary只会导致嵌套字典，数组和任意叶子的组合？

1) This data is coming from validated JSON. Is it safe to say that the NSDictionary created from a framework such as SBJSON (JSON Framework) would only result in a combination of nested dictionaries, arrays, and arbitrary leafs?

2）如何使用适用于数组和字典的快速枚举完成通用遍历？使用下面的代码，一旦我到达数组中的字典，它停止遍历。但是，如果我继续在数组条件递归（检查数组中的字典），它将在下一次迭代 id value = [dict valueForKey：key]; 与 - [__ NSCFDictionary长度]：无法识别的选择器发送到实例 SIGABRT。我不知道为什么这将是一个问题，因为我已经超过了一个顶级字典（其中发现了子级字典数组）。

2) How can a generic traversal be done using fast enumeration that works for both arrays and dictionaries? With the code below, once I get to a dictionary within an array, it stops traversing. However, if I continue the recursion in the array condition (to check for dictionaries within arrays), it barfs on the next iteration of id value = [dict valueForKey:key]; with a -[__NSCFDictionary length]: unrecognized selector sent to instance SIGABRT. I don't know why this would be a problem, because I already got past that line with a top-level dictionary (where the array of sub-level dictionaries were found).

-(void)processParsedObject:(id)dict counter:(int)i parent:(NSString *)parent
{
    for (id key in dict) {
        id value = [dict valueForKey:key];
        NSLog(@"%i : %@ : %@ -> %@", i, [value class], parent, key);

        if ([value isKindOfClass:[NSDictionary class]])
        {
            i++;
            NSDictionary* newDict = (NSDictionary*)value;
            [self processParsedObject:newDict counter:i parent:(NSString*)key];
            i--;
        }
        else if ([value isKindOfClass:[NSArray class]])
        {
            for (id obj in value) {
                NSLog(@"Obj Type: %@", [obj class]);
            }
        }
    }
}

感谢

推荐答案

我做了类似的事情，我将遍历一个来自一个Web服务的JSON结构化对象，一个可变的版本。

I've done something similar where I would traverse a JSON structured object coming from a web service and convert each element into a mutable version.

- (void)processParsedObject:(id)object
{
    [self processParsedObject:object depth:0 parent:nil];
}

- (void)processParsedObject:(id)object depth:(int)depth parent:(id)parent
{      
    if ([object isKindOfClass:[NSDictionary class]])
    {
        for (NSString* key in [object allKeys])
        {
            id child = [object objectForKey:key];
            [self processParsedObject:child depth:(depth + 1) parent:object];
        }
    }
    else if ([object isKindOfClass:[NSArray class]])
    {
        for (id child in object)
        {
            [self processParsedObject:child depth:(depth + 1) parent:object];
        }   
    }
    else
    {
        // This object is not a container you might be interested in it's value
        NSLog(@"Node: %@  depth: %d", [object description], depth);
    }
}

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