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nltk.html
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nltk.html
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<!DOCTYPE html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="theme-color" content="#2D2D2D" />
<title>NLTK :: nltk</title>
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<h1>
<a href="../index.html">NLTK</a>
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<h1>Documentation</h1>
</div>
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<p class="caption" role="heading"><span class="caption-text">NLTK Documentation</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../api/nltk.html">API Reference</a></li>
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<h1>Source code for nltk</h1><div class="highlight"><pre>
<span></span><span class="c1"># Natural Language Toolkit (NLTK)</span>
<span class="c1">#</span>
<span class="c1"># Copyright (C) 2001-2021 NLTK Project</span>
<span class="c1"># Authors: Steven Bird <stevenbird1@gmail.com></span>
<span class="c1"># Edward Loper <edloper@gmail.com></span>
<span class="c1"># URL: <https://www.nltk.org/></span>
<span class="c1"># For license information, see LICENSE.TXT</span>
<span class="sd">"""</span>
<span class="sd">The Natural Language Toolkit (NLTK) is an open source Python library</span>
<span class="sd">for Natural Language Processing. A free online book is available.</span>
<span class="sd">(If you use the library for academic research, please cite the book.)</span>
<span class="sd">Steven Bird, Ewan Klein, and Edward Loper (2009).</span>
<span class="sd">Natural Language Processing with Python. O'Reilly Media Inc.</span>
<span class="sd">https://www.nltk.org/book</span>
<span class="sd">isort:skip_file</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="c1"># //////////////////////////////////////////////////////</span>
<span class="c1"># Metadata</span>
<span class="c1"># //////////////////////////////////////////////////////</span>
<span class="c1"># Version. For each new release, the version number should be updated</span>
<span class="c1"># in the file VERSION.</span>
<span class="k">try</span><span class="p">:</span>
<span class="c1"># If a VERSION file exists, use it!</span>
<span class="n">version_file</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">dirname</span><span class="p">(</span><span class="vm">__file__</span><span class="p">),</span> <span class="s2">"VERSION"</span><span class="p">)</span>
<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="n">version_file</span><span class="p">)</span> <span class="k">as</span> <span class="n">infile</span><span class="p">:</span>
<span class="n">__version__</span> <span class="o">=</span> <span class="n">infile</span><span class="o">.</span><span class="n">read</span><span class="p">()</span><span class="o">.</span><span class="n">strip</span><span class="p">()</span>
<span class="k">except</span> <span class="ne">NameError</span><span class="p">:</span>
<span class="n">__version__</span> <span class="o">=</span> <span class="s2">"unknown (running code interactively?)"</span>
<span class="k">except</span> <span class="ne">OSError</span> <span class="k">as</span> <span class="n">ex</span><span class="p">:</span>
<span class="n">__version__</span> <span class="o">=</span> <span class="s2">"unknown (</span><span class="si">%s</span><span class="s2">)"</span> <span class="o">%</span> <span class="n">ex</span>
<span class="k">if</span> <span class="vm">__doc__</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span> <span class="c1"># fix for the ``python -OO``</span>
<span class="vm">__doc__</span> <span class="o">+=</span> <span class="s2">"</span><span class="se">\n</span><span class="s2">@version: "</span> <span class="o">+</span> <span class="n">__version__</span>
<span class="c1"># Copyright notice</span>
<span class="n">__copyright__</span> <span class="o">=</span> <span class="s2">"""</span><span class="se">\</span>
<span class="s2">Copyright (C) 2001-2021 NLTK Project.</span>
<span class="s2">Distributed and Licensed under the Apache License, Version 2.0,</span>
<span class="s2">which is included by reference.</span>
<span class="s2">"""</span>
<span class="n">__license__</span> <span class="o">=</span> <span class="s2">"Apache License, Version 2.0"</span>
<span class="c1"># Description of the toolkit, keywords, and the project's primary URL.</span>
<span class="n">__longdescr__</span> <span class="o">=</span> <span class="s2">"""</span><span class="se">\</span>
<span class="s2">The Natural Language Toolkit (NLTK) is a Python package for</span>
<span class="s2">natural language processing. NLTK requires Python 3.6, 3.7, 3.8, or 3.9."""</span>
<span class="n">__keywords__</span> <span class="o">=</span> <span class="p">[</span>
<span class="s2">"NLP"</span><span class="p">,</span>
<span class="s2">"CL"</span><span class="p">,</span>
<span class="s2">"natural language processing"</span><span class="p">,</span>
<span class="s2">"computational linguistics"</span><span class="p">,</span>
<span class="s2">"parsing"</span><span class="p">,</span>
<span class="s2">"tagging"</span><span class="p">,</span>
<span class="s2">"tokenizing"</span><span class="p">,</span>
<span class="s2">"syntax"</span><span class="p">,</span>
<span class="s2">"linguistics"</span><span class="p">,</span>
<span class="s2">"language"</span><span class="p">,</span>
<span class="s2">"natural language"</span><span class="p">,</span>
<span class="s2">"text analytics"</span><span class="p">,</span>
<span class="p">]</span>
<span class="n">__url__</span> <span class="o">=</span> <span class="s2">"https://www.nltk.org/"</span>
<span class="c1"># Maintainer, contributors, etc.</span>
<span class="n">__maintainer__</span> <span class="o">=</span> <span class="s2">"NLTK Team"</span>
<span class="n">__maintainer_email__</span> <span class="o">=</span> <span class="s2">"nltk.team@gmail.com"</span>
<span class="n">__author__</span> <span class="o">=</span> <span class="n">__maintainer__</span>
<span class="n">__author_email__</span> <span class="o">=</span> <span class="n">__maintainer_email__</span>
<span class="c1"># "Trove" classifiers for Python Package Index.</span>
<span class="n">__classifiers__</span> <span class="o">=</span> <span class="p">[</span>
<span class="s2">"Development Status :: 5 - Production/Stable"</span><span class="p">,</span>
<span class="s2">"Intended Audience :: Developers"</span><span class="p">,</span>
<span class="s2">"Intended Audience :: Education"</span><span class="p">,</span>
<span class="s2">"Intended Audience :: Information Technology"</span><span class="p">,</span>
<span class="s2">"Intended Audience :: Science/Research"</span><span class="p">,</span>
<span class="s2">"License :: OSI Approved :: Apache Software License"</span><span class="p">,</span>
<span class="s2">"Operating System :: OS Independent"</span><span class="p">,</span>
<span class="s2">"Programming Language :: Python :: 3.6"</span><span class="p">,</span>
<span class="s2">"Programming Language :: Python :: 3.7"</span><span class="p">,</span>
<span class="s2">"Programming Language :: Python :: 3.8"</span><span class="p">,</span>
<span class="s2">"Programming Language :: Python :: 3.9"</span><span class="p">,</span>
<span class="s2">"Topic :: Scientific/Engineering"</span><span class="p">,</span>
<span class="s2">"Topic :: Scientific/Engineering :: Artificial Intelligence"</span><span class="p">,</span>
<span class="s2">"Topic :: Scientific/Engineering :: Human Machine Interfaces"</span><span class="p">,</span>
<span class="s2">"Topic :: Scientific/Engineering :: Information Analysis"</span><span class="p">,</span>
<span class="s2">"Topic :: Text Processing"</span><span class="p">,</span>
<span class="s2">"Topic :: Text Processing :: Filters"</span><span class="p">,</span>
<span class="s2">"Topic :: Text Processing :: General"</span><span class="p">,</span>
<span class="s2">"Topic :: Text Processing :: Indexing"</span><span class="p">,</span>
<span class="s2">"Topic :: Text Processing :: Linguistic"</span><span class="p">,</span>
<span class="p">]</span>
<span class="kn">from</span> <span class="nn">nltk.internals</span> <span class="kn">import</span> <span class="n">config_java</span>
<span class="c1"># support numpy from pypy</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">import</span> <span class="nn">numpypy</span>
<span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="c1"># Override missing methods on environments where it cannot be used like GAE.</span>
<span class="kn">import</span> <span class="nn">subprocess</span>
<span class="k">if</span> <span class="ow">not</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">subprocess</span><span class="p">,</span> <span class="s2">"PIPE"</span><span class="p">):</span>
<span class="k">def</span> <span class="nf">_fake_PIPE</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="k">raise</span> <span class="ne">NotImplementedError</span><span class="p">(</span><span class="s2">"subprocess.PIPE is not supported."</span><span class="p">)</span>
<span class="n">subprocess</span><span class="o">.</span><span class="n">PIPE</span> <span class="o">=</span> <span class="n">_fake_PIPE</span>
<span class="k">if</span> <span class="ow">not</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">subprocess</span><span class="p">,</span> <span class="s2">"Popen"</span><span class="p">):</span>
<span class="k">def</span> <span class="nf">_fake_Popen</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="k">raise</span> <span class="ne">NotImplementedError</span><span class="p">(</span><span class="s2">"subprocess.Popen is not supported."</span><span class="p">)</span>
<span class="n">subprocess</span><span class="o">.</span><span class="n">Popen</span> <span class="o">=</span> <span class="n">_fake_Popen</span>
<span class="c1">###########################################################</span>
<span class="c1"># TOP-LEVEL MODULES</span>
<span class="c1">###########################################################</span>
<span class="c1"># Import top-level functionality into top-level namespace</span>
<span class="kn">from</span> <span class="nn">nltk.collocations</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.decorators</span> <span class="kn">import</span> <span class="n">decorator</span><span class="p">,</span> <span class="n">memoize</span>
<span class="kn">from</span> <span class="nn">nltk.featstruct</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.grammar</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.probability</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.text</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.tree</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.util</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.jsontags</span> <span class="kn">import</span> <span class="o">*</span>
<span class="c1">###########################################################</span>
<span class="c1"># PACKAGES</span>
<span class="c1">###########################################################</span>
<span class="kn">from</span> <span class="nn">nltk.chunk</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.classify</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.inference</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.metrics</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.parse</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.tag</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.tokenize</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.translate</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.sem</span> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">from</span> <span class="nn">nltk.stem</span> <span class="kn">import</span> <span class="o">*</span>
<span class="c1"># Packages which can be lazily imported</span>
<span class="c1"># (a) we don't import *</span>
<span class="c1"># (b) they're slow to import or have run-time dependencies</span>
<span class="c1"># that can safely fail at run time</span>
<span class="kn">from</span> <span class="nn">nltk</span> <span class="kn">import</span> <span class="n">lazyimport</span>
<span class="n">app</span> <span class="o">=</span> <span class="n">lazyimport</span><span class="o">.</span><span class="n">LazyModule</span><span class="p">(</span><span class="s2">"nltk.app"</span><span class="p">,</span> <span class="nb">locals</span><span class="p">(),</span> <span class="nb">globals</span><span class="p">())</span>
<span class="n">chat</span> <span class="o">=</span> <span class="n">lazyimport</span><span class="o">.</span><span class="n">LazyModule</span><span class="p">(</span><span class="s2">"nltk.chat"</span><span class="p">,</span> <span class="nb">locals</span><span class="p">(),</span> <span class="nb">globals</span><span class="p">())</span>
<span class="n">corpus</span> <span class="o">=</span> <span class="n">lazyimport</span><span class="o">.</span><span class="n">LazyModule</span><span class="p">(</span><span class="s2">"nltk.corpus"</span><span class="p">,</span> <span class="nb">locals</span><span class="p">(),</span> <span class="nb">globals</span><span class="p">())</span>
<span class="n">draw</span> <span class="o">=</span> <span class="n">lazyimport</span><span class="o">.</span><span class="n">LazyModule</span><span class="p">(</span><span class="s2">"nltk.draw"</span><span class="p">,</span> <span class="nb">locals</span><span class="p">(),</span> <span class="nb">globals</span><span class="p">())</span>
<span class="n">toolbox</span> <span class="o">=</span> <span class="n">lazyimport</span><span class="o">.</span><span class="n">LazyModule</span><span class="p">(</span><span class="s2">"nltk.toolbox"</span><span class="p">,</span> <span class="nb">locals</span><span class="p">(),</span> <span class="nb">globals</span><span class="p">())</span>
<span class="c1"># Optional loading</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">import</span> <span class="nn">numpy</span>
<span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="k">else</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">nltk</span> <span class="kn">import</span> <span class="n">cluster</span>
<span class="kn">from</span> <span class="nn">nltk.downloader</span> <span class="kn">import</span> <span class="n">download</span><span class="p">,</span> <span class="n">download_shell</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">import</span> <span class="nn">tkinter</span>
<span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">nltk.downloader</span> <span class="kn">import</span> <span class="n">download_gui</span>
<span class="k">except</span> <span class="ne">RuntimeError</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span>
<span class="kn">import</span> <span class="nn">warnings</span>
<span class="n">warnings</span><span class="o">.</span><span class="n">warn</span><span class="p">(</span>
<span class="s2">"Corpus downloader GUI not loaded "</span>
<span class="s2">"(RuntimeError during import: </span><span class="si">%s</span><span class="s2">)"</span> <span class="o">%</span> <span class="nb">str</span><span class="p">(</span><span class="n">e</span><span class="p">)</span>
<span class="p">)</span>
<span class="c1"># explicitly import all top-level modules (ensuring</span>
<span class="c1"># they override the same names inadvertently imported</span>
<span class="c1"># from a subpackage)</span>
<span class="kn">from</span> <span class="nn">nltk</span> <span class="kn">import</span> <span class="n">ccg</span><span class="p">,</span> <span class="n">chunk</span><span class="p">,</span> <span class="n">classify</span><span class="p">,</span> <span class="n">collocations</span>
<span class="kn">from</span> <span class="nn">nltk</span> <span class="kn">import</span> <span class="n">data</span><span class="p">,</span> <span class="n">featstruct</span><span class="p">,</span> <span class="n">grammar</span><span class="p">,</span> <span class="n">help</span><span class="p">,</span> <span class="n">inference</span><span class="p">,</span> <span class="n">metrics</span>
<span class="kn">from</span> <span class="nn">nltk</span> <span class="kn">import</span> <span class="n">misc</span><span class="p">,</span> <span class="n">parse</span><span class="p">,</span> <span class="n">probability</span><span class="p">,</span> <span class="n">sem</span><span class="p">,</span> <span class="n">stem</span><span class="p">,</span> <span class="n">wsd</span>
<span class="kn">from</span> <span class="nn">nltk</span> <span class="kn">import</span> <span class="n">tag</span><span class="p">,</span> <span class="n">tbl</span><span class="p">,</span> <span class="n">text</span><span class="p">,</span> <span class="n">tokenize</span><span class="p">,</span> <span class="n">translate</span><span class="p">,</span> <span class="n">tree</span><span class="p">,</span> <span class="n">treetransforms</span><span class="p">,</span> <span class="n">util</span>
<span class="c1"># FIXME: override any accidentally imported demo, see https://github.com/nltk/nltk/issues/2116</span>
<div class="viewcode-block" id="demo"><a class="viewcode-back" href="../api/nltk.html#nltk.demo">[docs]</a><span class="k">def</span> <span class="nf">demo</span><span class="p">():</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"To run the demo code for a module, type nltk.module.demo()"</span><span class="p">)</span></div>
</pre></div>
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