在表视图中显示之前过滤数组结果

Question

I need to filter the array I'm using so it doesn't show all of the results (want to only show first 20 of 100 leafs ) in my UITableView .

Can't figure out how to do it. Let me know if you would like more code posted!

(I'm using RestKit, pulling from an API, and already have the Object Mapping working fine)

ViewController.m

    @property (strong, nonatomic) NSArray *springs;
    @property (strong, nonatomic) NSMutableArray *leafs;

    - (void)viewDidLoad
    {
        [super viewDidLoad];
       [[RKObjectManager sharedManager] 
       loadObjectsAtResourcePath:@"/ss/?apikey=xx" 
       usingBlock:^(RKObjectLoader *loader) {
            loader.onDidLoadObjects = ^(NSArray *objects){

                  springs = objects;

// @cream-corn this is the for statement you suggested, but I can't finish it
        for (Sport *sport in objects){
                for (Leaf *leaf in spring.leafs){
                    if (leaf.abbreviation isEqualToString:@"ap"){
// This is where I can't figure out what to put
                        [];
                    }
                }
            }


              [_tableView reloadData];


          // @cream-corn this is where I log that I'm getting correct data
            for (Spring *sppring in objects){
             NSLog(@"%@", spring.name);
            for (Leaf *leaf in spring.leafs){
              NSLog(@"     %@ %@", leaf.name, leaf.abbreviation);
                 }
            }


            };

            [loader.mappingProvider  
        setMapping:[Spring mapping] 
        forKeyPath:@"springs"];
            loader.onDidLoadResponse = ^(RKResponse *response){

            };
        }];
    }

    - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
    {
        Spring *spring = [springs objectAtIndex:section];
        return spring.leafs.count;
    }

    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
    {
        static NSString *CellIdentifier = @"standardCell";
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

        Spring *spring = [springs objectAtIndex:indexPath.section];  // 13 objects
        Leaf *leaf = [spring.leafs objectAtIndex:indexPath.row];  // 30 objects

        cell.textLabel.text = leaf.shortName;
        return cell;
    }

Answer 1

okay, so. do you want to filter the array specifically? ie: remove objects that meet a certain condition? OR just display the first 20 in the table view?

If the former is correct (assuming that this array is mutable) you can do something like this: (this is a form of psudeocode this code won't copy/paste)

for(id obj in [myMutableArray reverseObjectEnumerator]) {
    if(obj does not meet condition) {

        [myMutableArray remove:obj]

    }
}

reverseObjectEnumerator is the most important piece of this loop, without it; it will throw an exception because you are mutating whilst enumerating.

If the latter is correct you can do this:

   - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection (NSInteger)section
{
    Spring *spring = [springs objectAtIndex:section];
    return MIN(spring.leafs.count, 20);
}

the line return MIN(spring.leafs.count,20); just returns the smaller number, either spring.leafs.count or 20