Question

I have a sorted array of NSString values, I would like to know how to capture the first letter of each string only when the first letter is different and put it in a new NSArray.

For instance if I have an array that was like like

"a, aaa, aaaa, b, c, d, dd, ddd"

it would be like this in the new NSArray

"a, b, c, d"

Any help would be greatly appreciated.

Answer 1

Something like this:

- (NSArray *)indexLettersForStrings:(NSArray *)strings {
    NSMutableArray *letters = [NSMutableArray array];
    NSString *currentLetter = nil;
    for (NSString *string in strings) {
        if (string.length > 0) {
            NSString *letter = [string substringToIndex:1];
            if (![letter isEqualToString:currentLetter]) {
                [letters addObject:letter];
                currentLetter = letter;
            }
        }
    }
    return [NSArray arrayWithArray:letters];
}