Find the maximum unique rulings on a Magic card.

most_rulings.py

#!/usr/bin/python3

import json

print("Loading ... ", end="")
with open("AllCards-x.json") as f:
    # that's http://mtgjson.com/json/AllSets-x.json.zip, unzipped
    cards = json.loads(f.read())
print("found {} cards.".format(len(cards)))

print("Filtering out tokens, planes, phenomena, schemes, and vanguards.")
filter_layouts = ["token", "plane", "scheme", "phenomenon", "vanguard"]
cards = {n:c for n,c in cards.items() if c["layout"] not in filter_layouts}

print("Collecting rulings.")
all_rulings = {}
for c in cards.values():
    for ruling in c.get("rulings", []):
        # set dict value to true iff the key was already there
        all_rulings[ruling["text"]] = ruling["text"] in all_rulings
# unique rulings are the keys corresponding to false values
print("Filtering duplicate rulings.")
unique_rulings = [r for r in all_rulings if not all_rulings[r]]

max_unique = 0
card_names = []
print("Counting unique rulings on {} cards ... ".format(len(cards)), end="")
for name, c in cards.items():
    rulings = c.get("rulings", [])
    if len(rulings) < max_unique:
        continue
    uniques = sum(1 for r in rulings if r["text"] in unique_rulings)
    if uniques > max_unique:
        max_unique = uniques
        card_names = [name]
    elif uniques == max_unique:
        card_names.append(name)
print("done.")

print("The most unique rulings on any card is {}.".format(max_unique))
print("Cards with that many:")
for name in card_names:
    print("  ", name)

output.txt

Loading ... found 16187 cards.
Filtering out tokens, planes, phenomena, schemes, and vanguards.
Collecting rulings.
Filtering duplicate rulings.
Counting unique rulings on 15928 cards ... done.
The most unique rulings on any card is 17.
Cards with that many:
   Lich's Mirror