fast research with nspredicate - iphone

Question

In my application i have a large table of around 20.000 items. I am displaying it on tableview. But the search bar is too slow while doing dynamic search. I have read that NSPredicate method is high performance then NSRange.
I don't know how applicate this method.
My code is :
- (void)filterContentForSearchText:(NSString*)searchText
{
[self.filteredListContent removeAllObjects];
for (Book *book in listContent)
{
NSRange range = [book.name rangeOfString:searchText options:NSCaseInsensitiveSearch];
// is very very slow
if (range.location != NSNotFound)
{
[self.filteredListContent addObject:book];
}
}
}
Where i must insert NSPredicate, into our out the "for"?

Answer 1

- (void)filterContentForSearchText:(NSString*)searchText
{
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"name contains %#", searchText ];
self.filteredListContent = [NSMutableArray arrayWithArray:[listContent filteredArrayUsingPredicate:predicate]];
}

Answer 2

If filtering for instance NSArray, you can use
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"job == 'Programmer'"]
[listOfItems filterUsingPredicate:predicate];
if you want to make a fetch request use
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"title == %#", aTitle];
[request setEntity:[NSEntityDescription entityForName:#"DVD" inManagedObjectContext:moc]];
[request setPredicate:predicate];
NSError *error = nil;
NSArray *results = [moc executeFetchRequest:request error:&error];
// error handling code
[request release];
EDIT:
ssteinberg's example is simple and good, just one note - you can modify an operator using the key characters c and d within square braces to specify case and diacritic insensitivity respectively. Example [NSPredicate predicateWithFormat:#"name contains[cd] %#", searchString];