CODEWITHSUNDEEP
iosobjective-cnsdictionary
user2529626
user2529626

Reputation:

Getting values from nested NSDictionary in Order?

dictionary = (_NSDictionaryM) 3 key/value pairs
    [0] = @"CELL2" : 1 : key/value pair
        key = (__NSCFString) @"CELL2"
        value = (__NSDictionaryM) 1 key/value pair
            [0] = @"download" : @"Text Response"
                key = (__NSCFString) @"download"
                value = (__NSCFString) "Text Response"
    [1] = @"CELL1" : 1 : key/value pair
        key = (__NSCFString) @"CELL1"
        value = (__NSDictionaryM) 1 key/value pair
            [0] = @"download" : @"Text Response"
                key = (__NSCFString) @"download"
                value = (__NSCFString) "Text Response"
    [2] = @"CELL3" : 1 : key/value pair
        key = (__NSCFString) @"CELL3"
        value = (__NSDictionaryM) 1 key/value pair
            [0] = @"download" : @"Text Response"
                key = (__NSCFString) @"download"
                value = (__NSCFString) "Text Response"

I have a dictionary that looks like above. Using fast enumeration, I can get the "Text Responses" (which is what I ultimately want, I don't care about anything else). The issue is that I need to also get them in order when I store them into an array. The order I do get them in is consistent per dictionary (I'll always get them in 2, 1, 3, for example), but different for each dictionary I'm going through.

Additional info: dictionary can have an arbitrary number of entries, but the inside of it is always the same, and I must pull the data out of a dictionary, it cannot be delivered to me in any other way.

The attempts I've tried end up with the same result I have currently (I get the text response but out of order) or it will throw a exception because I'm performing an action on something that doesn't respond to it.

Upvotes: 1

Views: 811

Answers (1)

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726509

Fast enumeration pulls dictionary keys in implementation-defined order (specifically, in the order consistent with hash codes of that dictionary's keys). If you need to enforce a specific order, pull the keys out of the dictionary into NSArray, sort that array to your liking, and then fast-iterate the array, pulling values from the dictionary for each key in the sorted order:

NSDictionary *dict = ...
// You can use any of the sortedArrayUsingXYZ methods below
NSArray *sortedKeys = [[dict allKeys] sortedArrayUsingDescriptors:...];
for (NSString *key in sortedKeys) {
    id obj = [dict getObjectForKey:key];
    ...
}

Upvotes: 3

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