IGWN LIGO Light-Weight XML I/O Library

2.1.1 verified Mon Apr 27 auth: no python

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.

pip install igwn-ligolw

Common errors

error ImportError: No module named 'ligolw' ↓

cause The package was renamed and the old name is not backwards compatible.

fix

Install igwn-ligolw: pip install igwn-ligolw

error ImportError: libxml2.so.2: cannot open shared object file ↓

cause Missing libxml2 runtime library.

fix

Install libxml2: sudo apt-get install libxml2 (or equivalent for your OS)

Warnings

breaking The package was renamed from 'python-ligo-lw' to 'igwn-ligolw'. Old installations will not update automatically. ↓

fix Uninstall the old package and install igwn-ligolw.

deprecated The top-level module 'ligolw' is used; do not import from 'igwn.ligolw'. ↓

fix Use 'import ligolw' directly.

gotcha The library relies on external dependencies like 'libxml2' for some features. Missing system libraries can cause import errors. ↓

fix Install system dependencies: sudo apt-get install libxml2-dev libxslt1-dev (Linux) or use conda.

Imports

ligolw
wrong
```
from igwn import ligolw
```
correct
```
import ligolw
```
The package is imported as 'ligolw', not 'igwn.ligolw'.
lsctables
wrong
```
from igwn.ligolw import lsctables
```
correct
```
from ligolw import lsctables
```
Submodules are under 'ligolw', not 'igwn.ligolw'.

Quickstart

Load a LIGO_LW XML file and print the document object.

import ligolw
from ligolw import utils
load_doc = utils.load_filename('test.xml', contenthandler=ligolw.LIGOLWContentHandler)
print(load_doc)