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<span id="reference-index"></span><h1>The Python Language Reference<a class="headerlink" href="#the-python-language-reference" title="Permalink to this headline">¶</a></h1>
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<p>This reference manual describes the syntax and “core semantics” of the
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language. It is terse, but attempts to be exact and complete. The semantics of
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non-essential built-in object types and of the built-in functions and modules
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are described in <a class="reference internal" href="../library/index.html#library-index"><span class="std std-ref">The Python Standard Library</span></a>. For an informal introduction to the
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language, see <a class="reference internal" href="../tutorial/index.html#tutorial-index"><span class="std std-ref">The Python Tutorial</span></a>. For C or C++ programmers, two additional
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manuals exist: <a class="reference internal" href="../extending/index.html#extending-index"><span class="std std-ref">Extending and Embedding the Python Interpreter</span></a> describes the high-level picture of how to
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write a Python extension module, and the <a class="reference internal" href="../c-api/index.html#c-api-index"><span class="std std-ref">Python/C API Reference Manual</span></a> describes the
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interfaces available to C/C++ programmers in detail.</p>
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<li class="toctree-l1"><a class="reference internal" href="introduction.html">1. Introduction</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="introduction.html#alternate-implementations">1.1. Alternate Implementations</a></li>
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<li class="toctree-l2"><a class="reference internal" href="introduction.html#notation">1.2. Notation</a></li>
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</ul>
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<li class="toctree-l1"><a class="reference internal" href="lexical_analysis.html">2. Lexical analysis</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="lexical_analysis.html#line-structure">2.1. Line structure</a></li>
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<li class="toctree-l2"><a class="reference internal" href="lexical_analysis.html#other-tokens">2.2. Other tokens</a></li>
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<li class="toctree-l2"><a class="reference internal" href="lexical_analysis.html#identifiers">2.3. Identifiers and keywords</a></li>
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<li class="toctree-l2"><a class="reference internal" href="lexical_analysis.html#literals">2.4. Literals</a></li>
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<li class="toctree-l2"><a class="reference internal" href="lexical_analysis.html#operators">2.5. Operators</a></li>
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<li class="toctree-l2"><a class="reference internal" href="lexical_analysis.html#delimiters">2.6. Delimiters</a></li>
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</ul>
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<li class="toctree-l1"><a class="reference internal" href="datamodel.html">3. Data model</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="datamodel.html#objects-values-and-types">3.1. Objects, values and types</a></li>
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<li class="toctree-l2"><a class="reference internal" href="datamodel.html#the-standard-type-hierarchy">3.2. The standard type hierarchy</a></li>
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<li class="toctree-l2"><a class="reference internal" href="datamodel.html#special-method-names">3.3. Special method names</a></li>
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<li class="toctree-l2"><a class="reference internal" href="datamodel.html#coroutines">3.4. Coroutines</a></li>
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</ul>
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<li class="toctree-l1"><a class="reference internal" href="executionmodel.html">4. Execution model</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="executionmodel.html#structure-of-a-program">4.1. Structure of a program</a></li>
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<li class="toctree-l2"><a class="reference internal" href="executionmodel.html#naming-and-binding">4.2. Naming and binding</a></li>
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<li class="toctree-l2"><a class="reference internal" href="executionmodel.html#exceptions">4.3. Exceptions</a></li>
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</ul>
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<li class="toctree-l1"><a class="reference internal" href="import.html">5. The import system</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="import.html#importlib">5.1. <code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib</span></code></a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#packages">5.2. Packages</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#searching">5.3. Searching</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#loading">5.4. Loading</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#the-path-based-finder">5.5. The Path Based Finder</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#replacing-the-standard-import-system">5.6. Replacing the standard import system</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#package-relative-imports">5.7. Package Relative Imports</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#special-considerations-for-main">5.8. Special considerations for __main__</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#open-issues">5.9. Open issues</a></li>
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<li class="toctree-l2"><a class="reference internal" href="import.html#references">5.10. References</a></li>
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</ul>
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</li>
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<li class="toctree-l1"><a class="reference internal" href="expressions.html">6. Expressions</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#arithmetic-conversions">6.1. Arithmetic conversions</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#atoms">6.2. Atoms</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#primaries">6.3. Primaries</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#await-expression">6.4. Await expression</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#the-power-operator">6.5. The power operator</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#unary-arithmetic-and-bitwise-operations">6.6. Unary arithmetic and bitwise operations</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#binary-arithmetic-operations">6.7. Binary arithmetic operations</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#shifting-operations">6.8. Shifting operations</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#binary-bitwise-operations">6.9. Binary bitwise operations</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#comparisons">6.10. Comparisons</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#boolean-operations">6.11. Boolean operations</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#conditional-expressions">6.12. Conditional expressions</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#lambda">6.13. Lambdas</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#expression-lists">6.14. Expression lists</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#evaluation-order">6.15. Evaluation order</a></li>
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<li class="toctree-l2"><a class="reference internal" href="expressions.html#operator-precedence">6.16. Operator precedence</a></li>
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</ul>
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<li class="toctree-l1"><a class="reference internal" href="simple_stmts.html">7. Simple statements</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#expression-statements">7.1. Expression statements</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#assignment-statements">7.2. Assignment statements</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-assert-statement">7.3. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">assert</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-pass-statement">7.4. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">pass</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-del-statement">7.5. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">del</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-return-statement">7.6. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">return</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-yield-statement">7.7. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">yield</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-raise-statement">7.8. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">raise</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-break-statement">7.9. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">break</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-continue-statement">7.10. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">continue</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-import-statement">7.11. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">import</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-global-statement">7.12. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">global</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="simple_stmts.html#the-nonlocal-statement">7.13. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">nonlocal</span></code> statement</a></li>
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<li class="toctree-l1"><a class="reference internal" href="compound_stmts.html">8. Compound statements</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#the-if-statement">8.1. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">if</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#the-while-statement">8.2. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">while</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#the-for-statement">8.3. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">for</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#the-try-statement">8.4. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">try</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#the-with-statement">8.5. The <code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code> statement</a></li>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#function-definitions">8.6. Function definitions</a></li>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#class-definitions">8.7. Class definitions</a></li>
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<li class="toctree-l2"><a class="reference internal" href="compound_stmts.html#coroutines">8.8. Coroutines</a></li>
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</ul>
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<li class="toctree-l1"><a class="reference internal" href="toplevel_components.html">9. Top-level components</a><ul>
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<li class="toctree-l2"><a class="reference internal" href="toplevel_components.html#complete-python-programs">9.1. Complete Python programs</a></li>
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<li class="toctree-l2"><a class="reference internal" href="toplevel_components.html#file-input">9.2. File input</a></li>
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<li class="toctree-l2"><a class="reference internal" href="toplevel_components.html#interactive-input">9.3. Interactive input</a></li>
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<li class="toctree-l2"><a class="reference internal" href="toplevel_components.html#expression-input">9.4. Expression input</a></li>
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<li class="toctree-l1"><a class="reference internal" href="grammar.html">10. Full Grammar specification</a></li>
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