https://errorvault.dev/tags/nameerror/Recent content in NameError on ErrorVault — Developer Error Code DictionaryHugoen-usSun, 12 Apr 2026 22:22:17 +0800https://errorvault.dev/python/python-nameerror-undefined-variable/Sun, 12 Apr 2026 22:22:17 +0800https://errorvault.dev/python/python-nameerror-undefined-variable/<h2 id="1-symptoms">1. Symptoms</h2> <p>NameError in Python occurs at runtime when code references a name (variable, function, class, or module) that is not defined in the current scope. The traceback typically shows:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#282a36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-gdscript3" data-lang="gdscript3"><span style="display:flex;"><span>Traceback (most recent call last): </span></span><span style="display:flex;"><span> File <span style="color:#f1fa8c">&#34;example.py&#34;</span>, line <span style="color:#bd93f9">5</span>, <span style="color:#ff79c6">in</span> <span style="color:#ff79c6">&lt;</span>module<span style="color:#ff79c6">&gt;</span> </span></span><span style="display:flex;"><span> <span style="color:#8be9fd;font-style:italic">print</span>(undefined_var) </span></span><span style="display:flex;"><span>NameError: name <span style="color:#f1fa8c">&#39;undefined_var&#39;</span> is <span style="color:#ff79c6">not</span> defined </span></span></code></pre></div><p>Key indicators:</p> <ul> <li>Error message: <code>NameError: name '{name}' is not defined</code></li> <li>Points to the exact line with the undefined reference.</li> <li>Common in scripts, functions, or after conditional definitions.</li> <li>No issue during syntax parsing; fails on execution.</li> </ul> <p>Variations include references to misspelled variables, functions called before definition, or globals accessed incorrectly in functions. IDEs like VS Code or PyCharm highlight these as warnings pre-runtime.</p>