Returning an object's index by dictionary value

Question

Here is my scenario: I have an array of dictionary items with 2 values.

array = (
    {
        id = 1;
        title = "Salon One";
    },
    {
        id = 2;
        title = "Salon Two";
    }
)

I'm not even sure if this is possible, but can I pass this array into a function and return an objects index based on a dictionary value?

- (int)getObjectIndex:(NSMutableArray *)array byName:(NSString *)theName{
    int index;

    /* Pseudo Code*/
    /*index = the index value in 'array' of objectForKey:@"title" = theName*/

    return index;
}

Answer 1

Of course it's possible, just loop through the array until you find the thing you're looking for

Answer 2

Why not?

- (NSInteger)getObjectIndex:(NSMutableArray *)array byName:(NSString *)theName {
    NSInteger idx = 0;
    for (NSDictionary* dict in array) {
        if ([[dict objectForKey:@"title"] isEqualToString:theName])
            return idx;
        ++idx;
    }
    return NSNotFound;
}

Note the slight difference in the signature (return type NSInteger vs int). This is necessary when using NSNotFound in 64 bit environments.

Answer 3

If you want to go super-fancy with blocks introduced in Snow Leopard, you could do:

- (BOOL (^)(id obj, NSUInteger idx, BOOL *stop))blockTestingForTitle:(NSString*)theName {
    return [[^(id obj, NSUInteger idx, BOOL *stop) {
     if ([[obj objectForKey:@"title"] isEqualToString:theName]) {
      *stop = YES;
      return YES;
     }
     return NO;
    } copy] autorelease];
}

and then whenever you want to find the index of a dictionary in an array:

[array indexOfObjectPassingTest:[self blockTestingForTitle:@"Salon One"]]