Question

I am trying to learn how to use predicates and so am trying to replace the following working code with filteredArrayUsingPredicate…

[filteredLocations removeAllObjects];
for (NSString *location in locations) {
  NSRange range = [location rangeOfString:query options:NSCaseInsensitiveSearch];
if (range.length > 0) {
      [filteredLocations addObject:location];
   }
  }

Instead I am trying….

[filteredLocations removeAllObjects];
NSPredicate *predicate =  [NSPredicate predicateWithFormat:@"SELF contains %@", searchText]; 
[filteredLocations addObjectsFromArray: [locations filteredArrayUsingPredicate:predicate]];

I am not getting the same results with the predicate as I am with for loop rangeOfString. With the range of string for example searchText returns an 8 item array while with the same value returns only 2 with the predicate. Another example, hono will find honolulu in the locations array while it will not find anything using the predicate.

As I understand it SELF represents the object object being evaluated ie. the locations array, so I think that is the correct syntax.

Any help would be appreciated

Thanks, John

Answer 1

I thought that in your for loop, you specify an option NSCaseInsensitiveSearch but in the predicate you didn’t.

You can try with this one

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(SELF contains[cd] %@)", searchText];

More details can be looked at here
NSPredicate Tutorial