If you just want the total number of items that satisfy your query, here is my Python3 code (using the pysolr module):
collection='bookindex' # or whatever your collection is called
solr_url = f"http://{SOLR_HOST}/solr/{collection}"
solr = pysolr.Solr(url=solr_url, timeout=120, always_commit=True)
result = solr.search("*:*", rows=0);
return result.hits
This queries for all documents (":") -- 315913 in my case -- but you can narrow that to suit your requirements. For example, if I want to know how many of my book entries have title:pandas I can search("title:pandas", rows=0) and get 41 as the number that have pandas in the title. By setting rows=0 you're letting Solr know that it need not format any results for you but you just return the meta information, and thus much more efficient than setting a high limit on rows.