PyStanfordDependencies
Python interface for converting Penn Treebank trees to Universal Dependencies and Stanford Dependencies.
Example usage
Start by getting a StanfordDependencies
instance with StanfordDependencies.get_instance()
:
>>> import StanfordDependencies >>> sd = StanfordDependencies.get_instance(backend='subprocess')
get_instance()
takes several options. backend
can currently be subprocess
or jpype
(see below). If you have an existing Stanford CoreNLP or Stanford Parser jar file, use the jar_filename
parameter to point to the full path of the jar file. Otherwise, PyStanfordDependencies will download a jar file for you and store it in locally (~/.local/share/pystanforddeps
). You can request a specific version with the version
flag, e.g., version='3.4.1'
. To convert trees, use the convert_trees()
or convert_tree()
method (note that by default, convert_trees()
can be considerably faster if you're doing batch conversion). These return a sentence (list of Token
objects) or a list of sentences (list of list of Token
objects) respectively:
>>> sent = sd.convert_tree('(S1 (NP (DT some) (JJ blue) (NN moose)))') >>> for token in sent: ... print token ... Token(index=1, form='some', cpos='DT', pos='DT', head=3, deprel='det') Token(index=2, form='blue', cpos='JJ', pos='JJ', head=3, deprel='amod') Token(index=3, form='moose', cpos='NN', pos='NN', head=0, deprel='root')
This tells you that moose
is the head of the sentence and is modified by some
(with a det
= determiner relation) and blue
(with an amod
= adjective modifier relation). Fields on Token
objects are readable as attributes. See docs for additional options in convert_tree()
and convert_trees()
.
Visualization
If you have the asciitree package, you can use a prettier ASCII formatter:
>>> print sent.as_asciitree() moose [root] +-- some [det] +-- blue [amod]
If you have Python 2.7 or later, you can use Graphviz to render your graphs. You'll need the Python graphviz package to call as_dotgraph()
:
>>> dotgraph = sent.as_dotgraph() >>> print dotgraph digraph { 0 [label=root] 1 [label=some] 3 -> 1 [label=det] 2 [label=blue] 3 -> 2 [label=amod] 3 [label=moose] 0 -> 3 [label=root] } >>> dotgraph.render('moose') # renders a PDF by default 'moose.pdf' >>> dotgraph.format = 'svg' >>> dotgraph.render('moose') 'moose.svg'
The Python xdot package provides an interactive visualization:
>>> import xdot >>> window = xdot.DotWindow() >>> window.set_dotcode(dotgraph.source)
Both as_asciitree()
and as_dotgraph()
allow customization. See the docs for additional options.
Backends
Currently PyStanfordDependencies includes two backends:
subprocess
(works anywhere with ajava
binary, but more overhead so batched conversions withconvert_trees()
are recommended)jpype
(requires jpype1, faster than the subprocess backend, also includes access to the Stanford CoreNLP lemmatizer)
By default, PyStanfordDependencies will attempt to use the jpype
backend. If jpype
isn't available or crashes on startup, PyStanfordDependencies will fallback to subprocess
with a warning.
Universal Dependencies status
PyStanfordDependencies supports most features in Universal Dependencies (see issue #10 for the most up to date status). PyStanfordDependencies output matches Universal Dependencies in terms of structure and dependency labels, but Universal POS tags and features are missing. Currently, PyStanfordDependencies will output Universal Dependencies by default (unless you're using Stanford CoreNLP 3.5.1 or earlier).
Related projects
- clearnlp-converter (uses clearnlp instead of Stanford CoreNLP for dependency conversion)
More information
Licensed under Apache 2.0.
Written by David McClosky (homepage, code)
Bug reports and feature requests: GitHub issue tracker
Release summaries
- 0.3.1 (2015.11.02): Better collapsed universal handling, bugfixes
- 0.3.0 (2015.10.09): Support copy nodes, more input checking/debugging help, example
convert.py
program - 0.2.0 (2015.08.02): Universal Dependencies support (mostly), Python 3 support (fully), minor API updates
- 0.1.7 (2015.06.13): Bugfixes for
JPype
, handle version mismatches in IBM Java - 0.1.6 (2015.02.12): Support for
graphviz
formatting, CoreNLP 3.5.1, better Windows portability - 0.1.5 (2015.01.10): Support for ASCII tree formatting
- 0.1.4 (2015.01.07): Fix
CCprocessed
support - 0.1.3 (2015.01.03): Bugfixes, coveralls integration, refactoring
- 0.1.2 (2015.01.02): Better CoNLL structures, test suite and Travis CI support, bugfixes
- 0.1.1 (2014.12.15): More docs, fewer bugs
- 0.1 (2014.12.14): Initial release