clinical-trial-prefixes.py

#!/usr/bin/env python3

# pip3 install requests

import requests

ignore_prefix = len('http://id.crossref.org/prefix/')

cursor = "*"

prefixes = {}

works = True
while works:
  message = requests.get("http://api.crossref.org/works",
                     params={"cursor": cursor,
                             "rows": 500,
                             "filter": "has-clinical-trial-number:true"}).json()['message']
  
  works = message['items']
  cursor = message['next-cursor']

  for work in works:
    prefix = work['prefix'][ignore_prefix:]
    prefixes[prefix] = prefixes.get(prefix,0) + 1

total = 0
for prefix, count in prefixes.items():
  prefix_owner = requests.get("http://api.crossref.org/prefixes/" + prefix).json()['message']['name']
  print("%s\t%s\t%d" % (prefix, prefix_owner, count))
  total += count

print("Total: %d" % total)