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Counting with dictionaries
9. Tuples as dictionary keys
Grouping with dictionaries
Linking with dictionaries


Good job! Now let's see an example of counting with tuples as dictionary keys.

Suppose we have a rectangular board with various flowers growing in various cells:

flowers = [
  ((0, 3), 'violet'), ((1, 2), 'sunflower'), ((0, 3), 'forget-me-not'),
  ((3, 4), 'violet'), ((0, 3), 'poppy'), ((1, 2), 'forget-me-not')


As you can see, there may be more than one flower in a given cell. We want to know how many flowers there are in each non-empty cell. Here's the code that will find the answer:

flower_counts = {}
for flower in flowers:
  position, _ = flower 
  flower_counts[position] = flower_counts.get(position, 0) + 1


{(0, 3): 3, (1, 2): 2, (3, 4): 1}

There are three flowers in the cell defined as (0, 3), two flowers in the cell (1, 2), and a single flower in (3, 4). Note that the keys in this example are tuples representing cell locations, but otherwise the entire code is similar to the previous examples.


Two distinct dice (e.g., blue and red) where rolled a few times. Each time we put the result in the tuple as (first_dice, second_dice).

Create a dictionary named results which will store the count of how many times a given combination was thrown.

Stuck? Here's a hint!

The code will be even simpler than the explanation code because you don't have to unpack anything.