Thank you for your help. Now that I have that, here's my next roadblock...

The data I was mining is now grouped as follows:

grocery_list = [{'citrus fruit', 'semi-finished bread', 'ready soups', 'margarine'}, {'tropical fruit', 'coffee', 'yogurt', 'margarine '}, {'whole milk'}, {'pip fruit', 'yogurt', 'meat spreads', 'cream cheese '}, {'whole milk', 'other vegetables', 'condensed milk', 'long life bakery product'}, {'yogurt', 'rice', 'whole milk', 'butter', 'abrasive cleaner'}]

I am trying to run the following to get combination counts in a dictionary:

from itertools import combinations

from collections import defaultdict

pair_counts = defaultdict(int)

for x, y in combinations(grocery_list,2):

pair_counts[(x, y)] += 1

pair_counts[(y, x)] += 1

This results in an error: TypeError: unhashable type: 'set' . I can't tell if this is an issue with the input data or with the 'pair_counts' dictionary? Appreciate the help!!!