ios - NSString characterSetWithCharactersInString returns empty strings -

i'm trying break nsstring comma separated components. somehow nsstring containing 25000 components returns 25.500 values, 500 of empty nsstrings. here's code looks like:

nsstring* filecontents = [nsstring stringwithcontentsoffile:filepath                                                     encoding:nsutf8stringencoding                                                       error:nil]; /* stuff */ nsmutablearray* components =   [nsmutablearray arraywitharray:    [filecontents componentsseparatedbycharactersinset:      [nscharacterset charactersetwithcharactersinstring:@",\n\r "]]]; 

consider example:

[@"\n,\n"componentsseparatedbycharactersinset:     [nscharacterset charactersetwithcharactersinstring:@",\n\r "]]; 

the result shows how componentsseparatedbycharactersinset: behaves. 4 components, empty strings. see why?

i'm not quite sure expecting do, do. splits @ of characters list. if 2 of them next each other, empty string. plus string before first 1 , string after last one.

so reason getting 25500 components that, given command gave, how many components there are.