Count knots with Arf invariant zero by crossing number

count_knots_with_arf_zero.py

import csv
import requests
from collections import Counter
import json

url = 'https://raw.githubusercontent.com/soehms/database_knotinfo/main/database_knotinfo/csv_data/knotinfo_data_complete.csv'

with requests.Session() as session:
    download = session.get(url)
    decoded = download.content.decode('utf-8')
    reader = csv.DictReader(decoded.splitlines(), delimiter='|')
    data = list(reader)

counts = Counter(int(row['crossing_number']) for row in data if row['arf_invariant'] == "0")
for crossing_number, count in sorted(counts.items()):
    print(crossing_number, count)