objective c - NSString - Convert to pure alphabet only (i.e. remove accents+punctuation)

Question

I'm trying to compare names without any punctuation, spaces, accents etc. At the moment I am doing the following:

-(NSString*) prepareString:(NSString*)a {
    //remove any accents and punctuation;
    a=[[[NSString alloc] initWithData:[a dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES] encoding:NSASCIIStringEncoding] autorelease];

    a=[a stringByReplacingOccurrencesOfString:@" " withString:@""];
    a=[a stringByReplacingOccurrencesOfString:@"'" withString:@""];
    a=[a stringByReplacingOccurrencesOfString:@"`" withString:@""];
    a=[a stringByReplacingOccurrencesOfString:@"-" withString:@""];
    a=[a stringByReplacingOccurrencesOfString:@"_" withString:@""];
    a=[a lowercaseString];
    return a;
}

However, I need to do this for hundreds of strings and I need to make this more efficient. Any ideas?

Answer 1

NSString* finish = [[start componentsSeparatedByCharactersInSet:[[NSCharacterSet letterCharacterSet] invertedSet]] componentsJoinedByString:@""];