extractMARCAuthToCSV.py

from pymarc import MARCReader
import csv
import argparse
import pandas as pd
import os
from datetime import datetime

parser = argparse.ArgumentParser()
parser.add_argument('-f', '--file')
args = parser.parse_args()

if args.file:
    filename = args.file
else:
    filename = input('Enter filename (including \'.mrc\'): ')


fileDir = os.path.dirname(__file__)

types_dict = {}
level_dict = {}
catsource_dict = {}


def createDict(csvname, column1, column2, dictname):
    with open(csvname) as codes:
        codes = csv.DictReader(codes)
        for row in codes:
            code = row[column1]
            name = row[column2]
            dictname[code] = name


#  Import type codes used in 008 field.
createDict(os.path.join(fileDir, 'dictionaries/marc_typeAuthorities.csv'), 'code', 'name', types_dict)
createDict(os.path.join(fileDir, 'dictionaries/marc_levelAuthorities.csv'), 'code', 'name', level_dict)
createDict(os.path.join(fileDir, 'dictionaries/marc_catsourceAuthorities.csv'), 'code', 'name', catsource_dict)


#  Creates k,v pair in dict where key = field_name, value = values of MARC tags in record.
def field_finder(record, field_name, tags):
    field_list = []
    field = record.get_fields(*tags)
    for my_field in field:
        my_field = my_field.format_field()
        field_list.append(my_field)
    if field_list:
        field_list = '|'.join(str(e) for e in field_list)
        mrc_fields[field_name] = field_list
    else:
        mrc_fields[field_name] = ''


# Creates k,v pair in dict where key = field_name, value = values of specific subfield in MARC tag in record.
def subfield_finder(record, field_name, subfields, tags):
    field_list = []
    field = record.get_fields(*tags)
    for my_field in field:
        my_subfield = my_field.get_subfields(*subfields)
        for field in my_subfield:
            field_list.append(field)
    if field_list:
        field_list = '|'.join(str(e) for e in field_list)
        mrc_fields[field_name] = field_list
    else:
        mrc_fields[field_name] = ''


# Converts code from MARC record into name from imported dictionaries.
def convert_to_name(keyname, dictname):
    for k, v in mrc_fields.items():
        if k == keyname:
            if isinstance(v, list):
                for count, item in enumerate(v):
                    for key, value in dictname.items():
                        if item == key:
                            v[count] = value
                mrc_fields[k] = v
            else:
                for key, value in dictname.items():
                    if v == key:
                        mrc_fields[k] = value


all_fields = []
record_count = 0
for filename in filenames:
    with open(filename, 'rb') as fh:
        marc_recs = MARCReader(fh, to_unicode=True)
        for record in marc_recs:
            mrc_fields = {}
            leader = record.leader
            #  Finds fields/subfield values in record.
            subfield_finder(record, 'number', subfields=['a'], tags=['010'])
            field_finder(record, 'headings', tags=['100', '110', '111', '130'])
            field_finder(record, 'desc', tags=['336', '368', '370', '371', '372', '373'])
            field_finder(record, 'alt_names', tags=['400', '410', '411', '430'])
            field_finder(record, 'see_also', tags=['510', '511', '530'])
            field_finder(record, 'unauthorized_forms', tags=['663', '664', '665', '666'])
            field_finder(record, 'linked_headings', tags=['710', '711'])
            field_finder(record, 'source', tags=['670'])
            field_finder(record, '008', tags=['008'])
            field_finder(record, 'last_updated', tags=['005'])
            mrc_fields['type'] = [leader[6]]

            # Edit & convert values in dictionary.
            for k, v in mrc_fields.items():
                # Find Lang codes, DtSt and Dates from field 008.
                if k == '008':
                    if v:
                        type = v[9]
                        level = v[33]
                        cat_source = v[39]
                    else:
                        type = ''
                        level = ''
                        cat_source = ''
                elif k == 'last_updated':
                    v = v[:4]
                    mrc_fields[k] = v
                elif k == 'number':
                    v = v.replace(" ", "").strip()
                    mrc_fields[k] = v

            del mrc_fields['008']
            mrc_fields['type'] = type
            mrc_fields['level'] = level
            mrc_fields['cat_source'] = cat_source
            convert_to_name('type', types_dict)
            convert_to_name('level', level_dict)
            convert_to_name('cat_source', catsource_dict)

            # Adds dict created by this MARC record to all_fields list.
            all_fields.append(mrc_fields)
            record_count = record_count + 1
            print(record_count)

df = pd.DataFrame.from_dict(all_fields)
print(df.head(15))
dt = datetime.now().strftime('%Y-%m-%d %H.%M.%S')
df.to_csv(path_or_buf='marcRecords_'+dt+'.csv', header='column_names', encoding='utf-8', sep=',', index=False)