text: import pandas as pd
  from collections import Counter
  from taxonomic import ncbi
  
  taxon_count = Counter()
  for chunk in pd.read_table('cold/GMGC10.taxonomic.reconciliation.map', chunksize=100_000, usecols=[3], squeeze=True):
      taxon_count.update(chunk.values)
  
  n = ncbi.NCBI()
  
  
  phclass = Counter()
  for k,v in taxon_count.items():
      kl = n.at_rank(str(k), 'class')
      p = n.at_rank(str(k), 'phylum')
      phclass[p,kl] += v
      
  
  data = pd.DataFrame([(ph,cl,c) for (ph,cl),c in phclass.items()], columns=['phylum', 'class', 'count'])
  data.sort_index(inplace=True)
  data.to_csv('tables/phylum-class.counts.txt', sep='\t', index=False)
  