{"id":27059,"library":"igwn-ligolw","title":"IGWN LIGO Light-Weight XML I/O Library","description":"A Python library for reading, writing, and manipulating LIGO Light-Weight XML (LIGO_LW) documents. Version 2.1.1 requires Python >=3.9. Development is active on GitHub.","status":"active","version":"2.1.1","language":"python","source_language":"en","source_url":"https://git.ligo.org/igwn/igwn-ligolw","tags":["ligo","xml","gravitational-waves"],"install":[{"cmd":"pip install igwn-ligolw","lang":"bash","label":"PyPI install"}],"dependencies":[],"imports":[{"note":"The package is imported as 'ligolw', not 'igwn.ligolw'.","wrong":"from igwn import ligolw","symbol":"ligolw","correct":"import ligolw"},{"note":"Submodules are under 'ligolw', not 'igwn.ligolw'.","wrong":"from igwn.ligolw import lsctables","symbol":"lsctables","correct":"from ligolw import lsctables"}],"quickstart":{"code":"import ligolw\nfrom ligolw import utils\nload_doc = utils.load_filename('test.xml', contenthandler=ligolw.LIGOLWContentHandler)\nprint(load_doc)","lang":"python","description":"Load a LIGO_LW XML file and print the document object."},"warnings":[{"fix":"Uninstall the old package and install igwn-ligolw.","message":"The package was renamed from 'python-ligo-lw' to 'igwn-ligolw'. Old installations will not update automatically.","severity":"breaking","affected_versions":">=2.0.0"},{"fix":"Use 'import ligolw' directly.","message":"The top-level module 'ligolw' is used; do not import from 'igwn.ligolw'.","severity":"deprecated","affected_versions":">=2.0.0"},{"fix":"Install system dependencies: sudo apt-get install libxml2-dev libxslt1-dev (Linux) or use conda.","message":"The library relies on external dependencies like 'libxml2' for some features. Missing system libraries can cause import errors.","severity":"gotcha","affected_versions":"all"}],"env_vars":null,"last_verified":"2026-04-27T00:00:00.000Z","next_check":"2026-07-26T00:00:00.000Z","problems":[{"fix":"Install igwn-ligolw: pip install igwn-ligolw","cause":"The package was renamed and the old name is not backwards compatible.","error":"ImportError: No module named 'ligolw'"},{"fix":"Install libxml2: sudo apt-get install libxml2 (or equivalent for your OS)","cause":"Missing libxml2 runtime library.","error":"ImportError: libxml2.so.2: cannot open shared object file"}],"ecosystem":"pypi","meta_description":null,"install_score":null,"install_tag":null,"quickstart_score":null,"quickstart_tag":null}