Filtering it right (it being the NSDictionary)

seecoolguy · May 2012

I've done a number of searches on this site and google, and perhaps I'm just missing the right keyword combinations to find examples on what I want to do.

I have an NSMutableDictionary that I need filtered then sorted (I know I need to put sorted values in an array, so really it's a 2 part question). Some searches on this forum brought me to this thread many other threads have been dead ends and I hope this wont be one of them.

If you know how to do this, please humor me and at least glance over my current dictionary and maybe you'll toss me a sample keyword that I can use to search more on, or maybe some sudo code that I can work with?

here are the results of my nsmutabledictionary:

{item =     {
        \"CONF_NO\" = 0004223624;
        COUNTER = 00000052;     
        \"OPERATION_NUMBER\" = 0199;
        };
item =     {
        \"CONF_NO\" = 0004223524;
        COUNTER = 00000002;     
        \"OPERATION_NUMBER\" = 0100;
        };
item =     {
        \"CONF_NO\" = 0004223520;
        COUNTER = 00000001;     
        \"OPERATION_NUMBER\" = 0001;
        };
};

now suppose I want to filter and sort by any key value for Operation_number that is between the range of 0100 to 0199. I looked up the documentation on Predicate from the Apple's Predicate Programming Guide, but I'm afraid that I'm still a little bit lost.

It seems that building a predicate would be the right approach, but it almost seems like I need a degree to figure how to construct a predicate for my dictionary object above. :-|

so I tried crafting this simple example by throwing together some snippets of code off the web but it doesn't seem like it's doable either :(


 NSPredicate *predicate = [NSPredicate
                              
                              predicateWithFormat:@\"(OPERATION_NUMBER >= %@) AND (OPERATION_NUMBER <= %@)\",
                              
                              @\"0100\", @\"0199\"];

doesn't seem to work, and it's quite possible I'm not doing it right :-|

Thank you for reading my post and if you can help, Thanks!

BrianSlick · May 2012

Are the operation numbers themselves stored as strings? That will be a problem. You'll need to convert them to numbers if you want to do math stuff.

seecoolguy · May 2012

BrianSlick;430771 said:
Are the operation numbers themselves stored as strings? That will be a problem. You'll need to convert them to numbers if you want to do math stuff.

Unfortunately yes, they are NSStrings from my Soap call :(, What would be a better approach?

Duncan C · May 2012

seecoolguy;430772 said:
Unfortunately yes, they are NSStrings from my Soap call :(, What would be a better approach?

Convert the values to NSNumber objects before storing them in your dictionary.

seecoolguy · May 2012

Duncan C;430774 said:
Convert the values to NSNumber objects before storing them in your dictionary.

I'd have to loop through original dictionary (results from sudzc) to convert it... but if that's the way, I'll loop, however if i'm looping I should just re-create a dictionary then with my filtered contents right?

BrianSlick · May 2012

Do you have a need for unfiltered contents?

seecoolguy · May 2012

BrianSlick;430777 said:
Do you have a need for unfiltered contents?

I do not, in fact I created a settings (standardUserDefaults) to hold filtered values that are needed at each iPad to be configurable for each user. The soap service that I call simply returns the entire payload and I just need small subsets like all row values from 0100 through 0199.

BrianSlick · May 2012

Then sure, take your raw data and process it however you need. If that means data conversion, then convert. If that means data removal, then remove.

seecoolguy · May 2012

Thanks!! This is what I came up with and it works, note I left the NSLogs in there on purpose, but this will filter my results down to just what is in the filterTo and filterFrom user configured filters. I imagine that there must be a way to default the filterTo to be 9999 if the NSUserDefault is null (because a filter could change while the app is already loaded).

    //Defaults
    int filterFrom = [[[NSUserDefaults standardUserDefaults] valueForKey:@\"FilterFrom\"] intValue]  ;
    int filterTo = [[[NSUserDefaults standardUserDefaults] valueForKey:@\"FilterTo\"] intValue];
    if (filterTo == 0)
       {filterTo = 9999;}
    NSDictionary *dict;
    for (dict in [objProdOrder allKeys])
        {
           
            if ([dict isKindOfClass:[NSDictionary class]]) {
                NSLog(@\"Found a Dictionary: %@\", [dict valueForKey:@\"OPERATION_NUMBER\"]);
            }
            else{
                NSLog(@\"Step#: %@\", [[objProdOrder objectForKey:dict] objectForKey:@\"OPERATION_NUMBER\"]);
                int intStep = [[[objProdOrder objectForKey:dict] objectForKey:@\"OPERATION_NUMBER\"] intValue];                
                if (intStep >= filterFrom && intStep <= filterTo)
                    {
                        //do nothing
                    }
                else {
                        NSLog(@\"Removing Step: %@\", dict);
                        [objProdOrder removeObjectForKey:dict];
                    }
            }   

        }

seecoolguy · May 2012

Thanks guys for helping me go in the right direction... here is the final part for my sorting, I looked up NSPredicate and other discussed methods even one that involves blocks, this version works for my needs... check it out:


NSArray *unSortedArray = [soapDictionary allKeys];
              
sortedArrayKeys = [unSortedArray sortedArrayUsingComparator: ^(id a, id b) {
                         NSString *first = [[soapDictionary objectForKey:a] objectForKey:@\"ITEM_NUMBER\"] ; 
                    NSString *second = [[soapDictionary objectForKey:b] objectForKey:@\"ITEM_NUMBER\"] ;
                    return [first compare:second];
                }];

That's it.. the Key value for ITEM_NUMBER is a value in my dictionary from the sudzc calls I made before I got into this mess ;). But now my sortedArrayKeys is tuned to a sorted list which is what my UITableView uses to display it's list... Thanks again for the pointers and helpful nudges :)

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Filtering it right (it being the NSDictionary)

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