import pandas as pd def issn(field): """Check if an ISSN is valid. Prints the ISSN if invalid. stdnum's is_valid() function never raises an exception. See: https://arthurdejong.org/python-stdnum/doc/1.11/index.html#stdnum.module.is_valid """ from stdnum import issn # Skip fields with missing values if pd.isna(field): return # Try to split multi-value field on "||" separator for value in field.split('||'): if not issn.is_valid(value): print(f'Invalid ISSN: {value}') def isbn(field): """Check if an ISBN is valid. Prints the ISBN if invalid. stdnum's is_valid() function never raises an exception. See: https://arthurdejong.org/python-stdnum/doc/1.11/index.html#stdnum.module.is_valid """ from stdnum import isbn # Skip fields with missing values if pd.isna(field): return # Try to split multi-value field on "||" separator for value in field.split('||'): if not isbn.is_valid(value): print(f'Invalid ISBN: {value}') def separators(field): """Check for invalid multi-value separators (ie "|" or "|||"). Prints the field with the invalid multi-value separator. """ import re # Skip fields with missing values if pd.isna(field): return # Try to split multi-value field on "||" separator for value in field.split('||'): # After splitting, see if there are any remaining "|" characters match = re.findall(r'^.*?\|.*$', value) if len(match) > 0: print(f'Invalid multi-value separator: {field}')