Objective-C: Count the number of times an object occurs in an array?

Question

I need to perform what I feel is a basic function but I can't find any documentation on how to do it. Please help!

I need to count how many times a certain object occurs in an array. See example:

array = NSArray arrayWithObjects:@"Apple", @"Banana", @"Cantaloupe", @"Apple", @"DragonFruit", @"Eggplant", @"Apple", @"Apple", @"Guava",nil]retain];

How can I iterate through the array and count the number of times it finds the string @"Apple"?

Any help is appreciated!

Answer 1

One more solution, using blocks (working example):

NSInteger occurrences = [[array indexesOfObjectsPassingTest:^(id obj, NSUInteger idx, BOOL *stop) {return [obj isEqual:@"Apple"];}] count];
NSLog(@"%d",occurrences);

Answer 2

As @bbum said, use an NSCounted set. There is an initializer thet will convert an array directly into a counted set:

    NSArray *array = [[NSArray alloc] initWithObjects:@"A", @"B", @"X", @"B", @"C", @"D", @"B", @"E", @"M", @"X", nil];
    NSCountedSet *countedSet = [[NSCountedSet alloc] initWithArray:array];
    NSLog(@"%@", countedSet);

NSLog output: (D [1], M [1], E [1], A [1], B [3], X [2], C [1])

Just access items:

count = [countedSet countForObject: anObj]; ...