I would like to loop through an `NSString` and call a custom function on every word that has certain criterion (For example, "has 2 'L's"). I was wondering what the best way of approaching that was. Should I use Find/Replace patterns? Blocks?

```
-(NSString *)convert:(NSString *)wordToConvert{
    /// This I have already written
    Return finalWord;
}

-(NSString *) method:(NSString *) sentenceContainingWords{
    // match every word that meets the criteria (for example the 2Ls) and replace it with what convert: does. 
}

```