Copying an Array

[djp_phillips]

Hello all,

I've started a project and I have an indexed UITableView displaying a list of data in sections (alphabet), I also have 3 buttons in the view and touching them allows the user to filter the data.

I have one button called "Browse all", another one called "Active" and the last one called "Inactive".

What I've put together is having an original array of data. And when I want to filter that, I copy that array into a temporary array and loop through each letter (section), and each entry per section (array of my data objects).

If according to the filter I should not be displaying a particular object in the list, I use NSMutableArray's removeObjectAtIndex method to remove that object.

All works fine but when I select Browse all after filtering the data previously, I realise that in fact when I used removeObjectAtIndex I actually made some objects release from memory.

Could anyone point out why in fact the items of my NSMutableDictionary reference the original objects and not a copy of these items ?

filteredArray = nil;

NSMutableArray* tmpArray = [fullArray mutableCopy];
if(filterActive){
    for (int u = 0; u < [tmpArray count]; u++) {
         NSMutableDictionary* d = [tmpArray objectAtIndex:u];
         NSMutableArray* dataObjects = [d objectForKey:@"Rows"];
         for(int i = 0; i < [dataObjects count]; i++){
              myObjectType* f = [dataObjects objectAtIndex:i];
              if(f.badge == 1){
                  [dataObjects removeObjectAtIndex:i];
                  i--;
               }
         }

         if([dataObjects count] == 0){
               [tmpArray removeObjectAtIndex:u];
               u--;
         }
     }
}

filteredArray = [[NSArray alloc] initWithArray:tmpArray];

// I use filteredArray as the data source for the UITableView

[BrianSlick]

The concept you are looking for is called "deep copy". What you are getting is a "shallow" copy.

If that is your entire method, you have a couple of leaks.

It depends on the situation, but I prefer to loop through the primary source, and then add matches to the separate array.

Edit:

You might be interested in initWithArray:copyItems: