pymods 
pymods is utility module for working with the Library of Congress's MODS XML standard: Metadata Description Schema (MODS). It is a utility wrapper for the lxml module specific to deserializing data out of MODSXML into python data types.
If you need a module to serialize data into MODSXML, see the other pymods by Matt Cordial.
Installing
Recommended:
pip install pymods
Using
Basics
XML is parsed using the MODSReader class:
mods_records = pymods.MODSReader('some_file.xml')
Individual records are stored as an iterator of the MODSRecord object:
In [5]: for record in mods_records:
....: print(record)
....:
<Element {http://www.loc.gov/mods/v3}mods at 0x47a69f8>
<Element {http://www.loc.gov/mods/v3}mods at 0x47fd908>
<Element {http://www.loc.gov/mods/v3}mods at 0x47fda48>MODSReader will work with mods:modsCollection documents, outputs from OAI-PMH feeds, or individual MODSXML documents with mods:mods as the root element.
pymods.MODSRecord
The MODSReader class parses each mods:mods element into a pymods.MODSRecord object. pymods.MODSRecord is a custom wrapper class for the lxml.ElementBase class. All children of pymods.Record inherit the lxml._Element and lxml.ElementBase methods.
In [6]: record = next(pymods.MODSReader('example.xml'))
In [7]: print(record.nsmap)
{'dcterms': 'http://purl.org/dc/terms/', 'xsi': 'http://www.w3.org/2001/XMLSchema-instance', None: 'http://www.loc.gov/mods/v3', 'flvc': 'info:flvc/manifest/v1', 'xlink': 'http://www.w3.org/1999/xlink', 'mods': 'http://www.loc.gov/mods/v3'}In [8]: for child in record.iterdescendants():
....: print(child.tag)
{http://www.loc.gov/mods/v3}identifier
{http://www.loc.gov/mods/v3}extension
{info:flvc/manifest/v1}flvc
{info:flvc/manifest/v1}owningInstitution
{info:flvc/manifest/v1}submittingInstitution
{http://www.loc.gov/mods/v3}titleInfo
{http://www.loc.gov/mods/v3}title
{http://www.loc.gov/mods/v3}name
{http://www.loc.gov/mods/v3}namePart
{http://www.loc.gov/mods/v3}role
{http://www.loc.gov/mods/v3}roleTerm
{http://www.loc.gov/mods/v3}roleTerm
{http://www.loc.gov/mods/v3}typeOfResource
{http://www.loc.gov/mods/v3}genre
...Methods
All functions return data either as a string, list, list of named tuples. See the appropriate docstring or the API documentation for details.
>>> record.genre?
Type: property
String form: <property object at 0x0000000004812C78>
Docstring:
Accesses mods:genre element.
:return: A list containing Genre elements with term, authority,
authorityURI, and valueURI attributes.Examples
Importing
from pymods import MODSReader, MODSRecordParsing a file
In [10]: mods = MODSReader('example.xml')
In [11]: for record in mods:
....: print(record.dates)
....:
[Date(text='1966-12-08', type='{http://www.loc.gov/mods/v3}dateCreated')]
None
[Date(text='1987-02', type='{http://www.loc.gov/mods/v3}dateIssued')]Simple tasks
Generating a title list
In [14]: for record in mods:
....: print(record.titles)
....:
['Fire Line System']
['$93,668.90. One Mill Tax Apportioned by Various Ways Proposed']
['Broward NOW News: National Organization for Women, February 1987']Creating a subject list
In [17]: for record in mods:
....: for subject in record.subjects:
....: print(subject.text)
....:
Concert halls
Architecture
Architectural drawings
Structural systems
Structural systems drawings
Structural drawings
Safety equipment
Construction
Mechanics
Structural optimization
Architectural design
Fire prevention--Safety measures
Taxes
Tax payers
Tax collection
Organizations
Feminism
Sex discrimination against women
Women's rights
Equal rights amendments
Women--Societies and clubs
National Organization for WomenMore complex tasks
Creating a list of subject URI's only for LCSH subjects
In [18]: for record in mods:
....: for subject in record.subjects:
....: if 'lcsh' == subject.authority:
....: print(subject.uri)
....:
http://id.loc.gov/authorities/subjects/sh85082767
http://id.loc.gov/authorities/subjects/sh88004614
http://id.loc.gov/authorities/subjects/sh85132810
http://id.loc.gov/authorities/subjects/sh85147343Get URLs for objects using a No Copyright US rightsstatement.org URI
In [23]: for record in mods:
....: for rights_elem in record.rights
....: if rights_elem.uri == 'http://rightsstatements.org/vocab/NoC-US/1.0/':
....: print(record.purl)
....:
http://purl.flvc.org/fsu/fd/FSU_MSS0204_B01_F10_09
http://purl.flvc.org/fsu/fd/FSU_MSS2008003_B18_F01_004