performance - iOS - searching in a large NSArray is slow -

i'm building customised uitableviewcontroller shows contacts in iphone , behaves abpeoplepickernavigationcontroller. meaning supports searching contacts. i'm doing code here.

i've implemented search ability using search bar , search display controller, , followed tutorial appcoda.

since nsarray array of abrecordref method of filtercontentforsearchtext: scope: this:

- (void)filtercontentforsearchtext:(nsstring*)searchtext scope:(nsstring*)scope {     nspredicate *resultpredicate = [nspredicate predicatewithblock:^bool(id evaluatedobject, nsdictionary *bindings) {         abrecordref person = (__bridge abrecordref)evaluatedobject;         nsstring * fullname = [self getfullnameofrecord:person];          nspredicate *tmppredicate = [nspredicate predicatewithformat:@"self contains[c] %@", searchtext];         if ([tmppredicate evaluatewithobject:fullname]) {             return yes;         } else {             nslog(@"tmppredicate didn't match");             return no;         }     }];      searchresults = [self.allcontacts filteredarrayusingpredicate:resultpredicate]; } 

the search results fine, since large array, works slowly. there way improve performance of search mechanism?

update: @eiko suggested, tried replacing inner nspredicate code:

nsrange range = [fullname rangeofstring:searchtext options:nscaseinsensitivesearch]; if (range.length > 0) {     return yes; } else {     return no; } 

but didn't improve performance.

you should try use profiler find weakest line, assume problem predicate block evaluated every entry every time.

i suggest create own wrapper class abrecordref (let's recordwrapper), contain link abrecordref whole data , cache frequent used , important values (e.g. fullname), can obtain once while loading list of contacts.

then if have array of recordwrapper* objects can filter calling

nspredicate *resultpredicate = [nspredicate predicatewithformat:@"fullname contains[c] %@", searchtext]; searchresults = [self.allcontactswrappers filteredarrayusingpredicate:resultpredicate]; 

this should increase filtering speed.