Question

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. 
}

Answer 1

The two ways I know of looping an array that will work for you are as follows:

NSArray *words = [sentence componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

for (NSString *word in words)
{
    NSString *transformedWord = [obj method:word];
}

and

NSArray *words = [sentence componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

[words enumerateObjectsWithOptions:NSEnumerationConcurrent usingBlock:^(id word, NSUInteger idx, BOOL *stop){
    NSString *transformedWord = [obj method:word];
}];

The other method, –makeObjectsPerformSelector:withObject:, won’t work for you. It expects to be able to call [word method:obj] which is backwards from what you expect.