TIL on EverythingPythonhttps://everythingpython.in/blog/til/Recent content in TIL on EverythingPythonHugoen-USContents under CC-BY-NCTue, 19 Nov 2024 00:00:00 +0000Dataclasseshttps://everythingpython.in/blog/dataclasses/Tue, 19 Nov 2024 00:00:00 +0000https://everythingpython.in/blog/dataclasses/<h3 id="19th-nov-2024">19th Nov 2024</h3> <p>I was trying to write an article on Dataclasses<sup id="fnref:1"><a href="#fn:1" class="footnote-ref" role="doc-noteref">1</a></sup> and I looked up an example on the official website<sup id="fnref:2"><a href="#fn:2" class="footnote-ref" role="doc-noteref">2</a></sup></p> <p>Easy enough on the face of it, but it led me into quite a rabbit hole. A dataclass allows for the creation of &ldquo;special methods&rdquo; for a class when the annotation @dataclass is sighted.</p> <p>So if I have a class &ldquo;Superhero&rdquo; with the annotation :</p> <div class="highlight"><pre tabindex="0" style="background-color:#f0f0f0;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-python" data-lang="python"><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 1</span><span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 2</span><span><span style="color:#555;font-weight:bold">@dataclass</span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 3</span><span><span style="color:#007020;font-weight:bold">class</span> <span style="color:#0e84b5;font-weight:bold">Superhero</span>: </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 4</span><span> <span style="color:#4070a0">&#34;&#34;&#34; </span></span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 5</span><span><span style="color:#4070a0"> A class of superheroes and properties about their appearance </span></span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 6</span><span><span style="color:#4070a0"> in Marvel movies </span></span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 7</span><span><span style="color:#4070a0"> &#34;&#34;&#34;</span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 8</span><span> name: <span style="color:#007020">str</span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f"> 9</span><span> superpower: <span style="color:#007020">str</span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">10</span><span> appearances: <span style="color:#007020">int</span> <span style="color:#666">=</span> <span style="color:#40a070">0</span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">11</span><span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">12</span><span> <span style="color:#007020;font-weight:bold">def</span> <span style="color:#06287e">beckon</span>(<span style="color:#007020">self</span>): </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">13</span><span> <span style="color:#007020">print</span>(<span style="color:#4070a0">f</span><span style="color:#4070a0">&#34;</span><span style="color:#70a0d0">{</span><span style="color:#007020">self</span><span style="color:#666">.</span>name<span style="color:#70a0d0">}</span><span style="color:#4070a0"> with the super power - </span><span style="color:#70a0d0">{</span><span style="color:#007020">self</span><span style="color:#666">.</span>superpower<span style="color:#70a0d0">}</span><span style="color:#4070a0"> has appeared in Marvel movies </span><span style="color:#70a0d0">{</span><span style="color:#007020">self</span><span style="color:#666">.</span>appearances<span style="color:#70a0d0">}</span><span style="color:#4070a0"> times&#34;</span>) </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">14</span><span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">15</span><span> </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">16</span><span>superhero <span style="color:#666">=</span> Superhero(<span style="color:#4070a0">&#34;Aquaman&#34;</span>,<span style="color:#4070a0">&#34;Underwater breathing&#34;</span>,<span style="color:#40a070">2</span>) </span></span><span style="display:flex;"><span style="white-space:pre;-webkit-user-select:none;user-select:none;margin-right:0.4em;padding:0 0.4em 0 0.4em;color:#7f7f7f">17</span><span>superhero<span style="color:#666">.</span>beckon() </span></span></code></pre></div><p>It effectively means that :</p>