An algorithm for diffing Magic: The Gathering lists (decks, cubes, etc.)

pip install -r requirements.txt

Visit https://scryfall.com/docs/api/bulk-data and download the "Oracle Cards" file into to this program's folder. The program will automatically read the matching file with the latest timestamp.

python diff.py list_a.txt list_b.txt > output.html

Two filenames containing card lists are passed as arguments, and the HTML diff report is written to standard out. Pipe that to the desired output file.

The lists should be simple text files containing one card name per line, optionally with a leading numeric multiplicity.

Example:

  Borrowing 100,000 Arrows
  2 Ajani's Pridemate

is interpreted as

  Borrowing 100,000 Arrows
  Ajani's Pridemate
  Ajani's Pridemate

The program constructs a cost matrix for assigning each card in List A with each card in List B. Then it applies a Linear Sum Assignment solver to minimize the total score for the assignment.

The cost metric is the key to the quality of the matching. The cost metric defines the "distance" between any two cards on the two lists. The algorithm minimizes the sum of the distance between all the cards that are matched to one another.

The metric mostly uses mana value, color identity, and text similarity to define the distance.