loop over a series of MARC files to extract record numbers, with hints to figure out which records are missing them

gistfile1.py

# loop over a series of MARC files to extract record numbers, with hints to figure out which records are missing them
import pymarc
c = 0
w = open('ids','w')
for f in ('hspall', 'lcpraream', 'lcprarenot', 'lcpnotrare'):
  r = pymarc.MARCReader(file(f))
  for _ in r:
    c += 1
    try:
      w.write(_['001'].format_field() + '\n')
    except AttributeError:
      w.write('==missing\n')
      a = pymarc.map_marc8_record(_)
      print a.__str__().encode('utf-8')
      raw_input()
    if (c % 1000 == 0):
      print c
w.close()