StackOverflow2013

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copied!<p>You can loop thru all of your items in the array and build a side-array only containing names of the day (1), or you can use a predicate and then KVC to extract the days directly (2).</p> <p>Then join the components of the filtered array into a string.</p> <p>Solution 1:</p> <pre><code>NSMutableArray selectedDays = [[NSMutableArray alloc] init]; for(NSDictionary* entry in sourceArray) { if (([entry objectForKey:@"isSelected"] boolValue]) { [selectedDays addObject:[entry objectForKey:@"day"]]; } } NSString days = [selectedDays componentsJoinedByString:@", "]; [selectedDays release]; </code></pre> <p>Solution 2:</p> <pre><code>NSPredicate* filter = [NSPredicate predicateWithFormat:@"SELF.isSelected == 1"]; // not sure about the exact format (no mac here to test right now so you may adapt a bit if it does not work directly) // get the array of dictionaries but only the ones that have isSelected==1 NSArray selectedEntries = [sourceArray filteredArrayUsingPredicate:filter]; NSArray selectedDays = [selectedEntries valueForKey:@"day"]; // extract the "days" keys of the dictionaries. We have a NSArray of strings then. NSString days = [selectedDays componentsJoinedByString:@", "]; </code></pre> <hr> <p>As a side note, your way of doing this is quite strange. Why having an NSArray of NSDictionaries for this? As this is simple and a static-size array containing only BOOL, you may instead for this particular case simply use C array <code>BOOL selected[7]</code> and nothing more.</p> <p>Then to have the name of the weekdays you should instead use the methods of <code>NSCalendar</code>/<code>NSDateFormatter</code>/<code>NSDateComponents</code> to get the standard names of the weekdays (automatically in the right language/locale of the user): <em>create an <code>NSDate</code> using a <code>NSDateComponent</code> for which you simply define the weekday component, then use an <code>NSDateFormatter</code> to convert this to a string, choosing a string format that only display the weekday name.</em></p> <hr> <pre><code>-(void)tableView:(UITableView*)tv didSelectRowAtIndexPath:(NSIndexPath*)indexPath { // selectedDays is an instance variable in .h declared as // BOOL selectedDays[7]; selectedDays[indexPath.row] = ! selectedDays[indexPath.row]; [tv reloadData]; } -(UITableViewCell*)tableView:(UITableView*)tv cellForRowAtIndexPath:(NSIndexPath*)indexPath { static NSString* kCellIdentifier = @"DayCell"; UITableViewCell* cell = [tv dequeueReusableCellWithIdentifier:kCellIdentifier]; if (!cell) { cell = [[[UITableViewCell alloc] initWithStyle:... identifier:kCellIdentifier]; autorelease]; // configure here every property that is common to all for your cells (text color, etc) } // configure here things that will change from cell to cell cell.accessoryType = selectedDays[indexPath.row] ? UITableViewCellAccessoryTypeCheckmarck : UITableViewCellAccessoryTypeNone; cell.textLabel.text = weekdayName(indexPath.row); return cell; } // Simple C function to return the name of a given weekday NSString* weekdayName(int weekday) { #if WAY_1 /**** Solution 1 ****/ // Optimization note: You may compute this once for all instead of recomputing it each time NSDateComponents* comp = [[[NSDateComponents alloc] init] autorelease]; [comp setWeekday:weekday+1]; // weekdays start at 1 for NSDateComponents NSDate* d = [[NSCalendar currentCalendar] dateFromComponents:comp]; NSDateFormatter* df = [[[NSDateFormatter alloc] init] autorelease]; [df setDateFormat:@"EEEE"]; // format for the weekday return [[df stringFromDate:d] capitalizedString]; #else /**** Solution 2 ****/ NSDateFormatter* df = [[[NSDateFormatter alloc] init] autorelease]; NSArray* weekdayNames = [df weekdaySymbols]; // or maybe one of its sibling methods? check what is returned here to be sure return [weekdayNames objectAtIndex:weekday]; #endif } </code></pre>

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