Latest posts on Помогите понять как работают методы __iter__ и __next__ topichttps://python.su/forum/topic/41370/2022-03-30T12:39:18+03:00Общий :: Python для новичков :: Помогите понять как работают методы __iter__ и __next__
2022-03-30T12:39:18+03:00vladimir_vl_vlad221228В общем, есть простая функция, находящая простые числа. С ней все понятно. Но у меня задание создать класс итерируемых объектов, который будет делать тоже самое. И тут я в тупике: я понимаю, что код внутри метода __next__ должен итерироваться поэтому никаких списков внутри него быть не должно (это противоречит самой идее итератора) Но как запилить решение задачи без использования списка я не понимаю. Буду рад помощи. <br/>Функция:<br/> <div class="code"><pre> <span class="k">def</span> <span class="nf">get_prime_numbers</span><span class="p">(</span><span class="n">n</span><span class="p">):</span>
<span class="n">prime_numbers</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">number</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="n">n</span><span class="o">+</span><span class="mi">1</span><span class="p">):</span>
<span class="k">for</span> <span class="n">prime</span> <span class="ow">in</span> <span class="n">prime_numbers</span><span class="p">:</span>
<span class="k">if</span> <span class="n">number</span> <span class="o">%</span> <span class="n">prime</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="k">break</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">prime_numbers</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">number</span><span class="p">)</span>
<span class="k">return</span> <span class="n">prime_numbers</span>
</pre></div>Мой вариант решения (нерабочий):<br/> <div class="code"><pre> <span class="k">class</span> <span class="nc">PrimeNumbers</span><span class="p">:</span>
<span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">n</span> <span class="o">=</span> <span class="n">n</span>
<span class="bp">self</span><span class="o">.</span><span class="n">number</span> <span class="o">=</span> <span class="mi">0</span>
<span class="bp">self</span><span class="o">.</span><span class="n">prime</span> <span class="o">=</span> <span class="mi">2</span>
<span class="k">def</span> <span class="fm">__iter__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">number</span> <span class="o">=</span> <span class="mi">0</span>
<span class="bp">self</span><span class="o">.</span><span class="n">prime</span> <span class="o">=</span> <span class="mi">2</span>
<span class="k">return</span> <span class="bp">self</span>
<span class="k">def</span> <span class="nf">__next__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">number</span> <span class="o">+=</span> <span class="mi">1</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">number</span> <span class="o">></span> <span class="bp">self</span><span class="o">.</span><span class="n">n</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">StopIteration</span><span class="p">()</span>
<span class="k">for</span> <span class="bp">self</span><span class="o">.</span><span class="n">number</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">n</span><span class="o">+</span><span class="mi">1</span><span class="p">):</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">number</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="n">prime</span> <span class="o">!=</span> <span class="mi">0</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">prime</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">number</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">prime</span>
<span class="n">prime_number_iterator</span> <span class="o">=</span> <span class="n">PrimeNumbers</span><span class="p">(</span><span class="n">n</span><span class="o">=</span><span class="mi">10000</span><span class="p">)</span>
<span class="k">for</span> <span class="n">number</span> <span class="ow">in</span> <span class="n">prime_number_iterator</span><span class="p">:</span>
<span class="k">print</span><span class="p">(</span><span class="n">number</span><span class="p">)</span>
</pre></div>