Added more instructive examples of list comprehensions.

Author: fedor1113

Matrices.py

@@ -12014,6 +12014,93 @@ <h4 id="&#1040;&#1073;&#1089;&#1090;&#1088;&#1072;&#1082;&#1094;&#1080;&#1080;-&
 
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+</div></section><section>
+<div class="cell border-box-sizing text_cell rendered"><div class="prompt input_prompt">
+</div>
+<div class="inner_cell">
+<div class="text_cell_render border-box-sizing rendered_html">
+<h5 id="&#1053;&#1072;&#1075;&#1083;&#1103;&#1076;&#1085;&#1086;&#1077;-&#171;&#1088;&#1072;&#1079;&#1074;&#1086;&#1088;&#1072;&#1095;&#1080;&#1074;&#1072;&#1085;&#1080;&#1077;&#187;-&#1072;&#1073;&#1089;&#1090;&#1088;&#1072;&#1082;&#1094;&#1080;&#1080;-&#1089;&#1087;&#1080;&#1089;&#1082;&#1086;&#1074;">&#1053;&#1072;&#1075;&#1083;&#1103;&#1076;&#1085;&#1086;&#1077; &#171;&#1088;&#1072;&#1079;&#1074;&#1086;&#1088;&#1072;&#1095;&#1080;&#1074;&#1072;&#1085;&#1080;&#1077;&#187; &#1072;&#1073;&#1089;&#1090;&#1088;&#1072;&#1082;&#1094;&#1080;&#1080; &#1089;&#1087;&#1080;&#1089;&#1082;&#1086;&#1074;<a class="anchor-link" href="#&#1053;&#1072;&#1075;&#1083;&#1103;&#1076;&#1085;&#1086;&#1077;-&#171;&#1088;&#1072;&#1079;&#1074;&#1086;&#1088;&#1072;&#1095;&#1080;&#1074;&#1072;&#1085;&#1080;&#1077;&#187;-&#1072;&#1073;&#1089;&#1090;&#1088;&#1072;&#1082;&#1094;&#1080;&#1080;-&#1089;&#1087;&#1080;&#1089;&#1082;&#1086;&#1074;">&#182;</a></h5><p>Разобранная выше сокращённая запись  <code>l1 = [f1(e) if cond(e) else f2(e) for e in iterable]</code> будет эквивалентна следующему коду.</p>
+<div class="highlight"><pre><span></span><span class="n">l1</span> <span class="o">=</span> <span class="p">[]</span>
+<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">iterable</span><span class="p">:</span>
+    <span class="k">if</span> <span class="n">cond</span><span class="p">(</span><span class="n">e</span><span class="p">):</span>
+        <span class="n">l1</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">f1</span><span class="p">(</span><span class="n">e</span><span class="p">))</span>
+    <span class="k">else</span><span class="p">:</span>
+        <span class="n">l1</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">f2</span><span class="p">(</span><span class="n">e</span><span class="p">))</span>
+</pre></div>
+
+</div>
+</div>
+</div></section><section>
+<div class="cell border-box-sizing text_cell rendered"><div class="prompt input_prompt">
+</div>
+<div class="inner_cell">
+<div class="text_cell_render border-box-sizing rendered_html">
+<h5 id="&#1041;&#1086;&#1083;&#1077;&#1077;-&#1089;&#1083;&#1086;&#1078;&#1085;&#1099;&#1081;-&#1087;&#1088;&#1080;&#1084;&#1077;&#1088;">&#1041;&#1086;&#1083;&#1077;&#1077; &#1089;&#1083;&#1086;&#1078;&#1085;&#1099;&#1081; &#1087;&#1088;&#1080;&#1084;&#1077;&#1088;<a class="anchor-link" href="#&#1041;&#1086;&#1083;&#1077;&#1077;-&#1089;&#1083;&#1086;&#1078;&#1085;&#1099;&#1081;-&#1087;&#1088;&#1080;&#1084;&#1077;&#1088;">&#182;</a></h5><p>Списковое включение:</p>
+<div class="highlight"><pre><span></span><span class="n">dimensions</span> <span class="o">=</span> <span class="p">(</span><span class="mi">7</span><span class="p">,</span> <span class="mi">6</span><span class="p">);</span> <span class="n">d</span> <span class="o">=</span> <span class="n">dimensions</span>
+<span class="n">s</span> <span class="o">=</span> <span class="s2">&quot;111000101000111000100101100010100010000100&quot;</span>
+<span class="n">l1</span> <span class="o">=</span> <span class="p">[[</span><span class="n">s</span><span class="p">[</span><span class="n">r</span> <span class="o">*</span> <span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">c</span><span class="p">]</span> <span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">])]</span> <span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">0</span><span class="p">])]</span>
+<span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="n">l1</span><span class="p">:</span>
+    <span class="k">print</span><span class="p">(</span><span class="o">*</span><span class="n">r</span><span class="p">,</span> <span class="n">sep</span><span class="o">=</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
+</pre></div>
+<p>Развёрнутый вариант:</p>
+<div class="highlight"><pre><span></span><span class="n">dimensions</span> <span class="o">=</span> <span class="p">(</span><span class="mi">7</span><span class="p">,</span> <span class="mi">6</span><span class="p">);</span> <span class="n">d</span> <span class="o">=</span> <span class="n">dimensions</span>
+<span class="n">s</span> <span class="o">=</span> <span class="s2">&quot;111000101000111000100101100010100010000100&quot;</span>
+<span class="n">l1</span> <span class="o">=</span> <span class="p">[]</span>
+<span class="p">[</span><span class="n">s</span><span class="p">[</span><span class="n">r</span> <span class="o">*</span> <span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">c</span><span class="p">]</span> <span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">])]</span> <span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
+<span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">0</span><span class="p">]):</span>
+    <span class="n">l1</span><span class="o">.</span><span class="n">append</span><span class="p">([])</span>
+    <span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">]):</span>
+        <span class="n">l1</span><span class="p">[</span><span class="n">r</span><span class="p">]</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">s</span><span class="p">[</span><span class="n">r</span> <span class="o">*</span> <span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">c</span><span class="p">])</span>
+<span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="n">l1</span><span class="p">:</span>
+    <span class="k">print</span><span class="p">(</span><span class="o">*</span><span class="n">r</span><span class="p">,</span> <span class="n">sep</span><span class="o">=</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
+</pre></div>
+
+</div>
+</div>
+</div></section><section>
+<div class="cell border-box-sizing code_cell rendered">
+<div class="input">
+<div class="prompt input_prompt">In&nbsp;[2]:</div>
+<div class="inner_cell">
+    <div class="input_area">
+<div class=" highlight hl-ipython3"><pre><span></span><span class="n">dimensions</span> <span class="o">=</span> <span class="p">(</span><span class="mi">7</span><span class="p">,</span> <span class="mi">6</span><span class="p">);</span> <span class="n">d</span> <span class="o">=</span> <span class="n">dimensions</span>
+<span class="n">s</span> <span class="o">=</span> <span class="s2">&quot;111000101000111000100101100010100010000100&quot;</span>
+<span class="n">l1</span> <span class="o">=</span> <span class="p">[[</span><span class="s2">&quot;#&quot;</span> <span class="k">if</span> <span class="n">s</span><span class="p">[</span><span class="n">r</span> <span class="o">*</span> <span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">c</span><span class="p">]</span> <span class="o">==</span> <span class="s2">&quot;1&quot;</span>
+       <span class="k">else</span> <span class="s2">&quot; &quot;</span>
+       <span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">1</span><span class="p">])]</span> 
+      <span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">d</span><span class="p">[</span><span class="mi">0</span><span class="p">])]</span>
+<span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="n">l1</span><span class="p">:</span>
+    <span class="nb">print</span><span class="p">(</span><span class="o">*</span><span class="n">r</span><span class="p">,</span> <span class="n">sep</span><span class="o">=</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
+</pre></div>
+
+</div>
+</div>
+</div>
+
+<div class="output_wrapper">
+<div class="output">
+
+
+<div class="output_area">
+
+<div class="prompt"></div>
+
+
+<div class="output_subarea output_stream output_stdout output_text">
+<pre>###   
+# #   
+###   
+#  # #
+#   # 
+#   # 
+   #  
+</pre>
+</div>
+</div>
+
+</div>
+</div>
+
 </div></section></section><section><section>
 <div class="cell border-box-sizing text_cell rendered"><div class="prompt input_prompt">
 </div>

index.html

@@ -151,6 +151,94 @@
     "```\n"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "subslide"
+    }
+   },
+   "source": [
+    "##### Наглядное «разворачивание» абстракции списков\n",
+    "\n",
+    "Разобранная выше сокращённая запись  ```l1 = [f1(e) if cond(e) else f2(e) for e in iterable]``` будет эквивалентна следующему коду.\n",
+    "\n",
+    " ```python \n",
+    "l1 = []\n",
+    "for e in iterable:\n",
+    "    if cond(e):\n",
+    "        l1.append(f1(e))\n",
+    "    else:\n",
+    "        l1.append(f2(e))\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "subslide"
+    }
+   },
+   "source": [
+    "##### Более сложный пример\n",
+    "Списковое включение:\n",
+    " ```python \n",
+    "dimensions = (7, 6); d = dimensions\n",
+    "s = \"111000101000111000100101100010100010000100\"\n",
+    "l1 = [[s[r * d[1] + c] for c in range(d[1])] for r in range(d[0])]\n",
+    "for r in l1:\n",
+    "    print(*r, sep=\"\")\n",
+    "```\n",
+    "Развёрнутый вариант:\n",
+    " ```python \n",
+    "dimensions = (7, 6); d = dimensions\n",
+    "s = \"111000101000111000100101100010100010000100\"\n",
+    "l1 = []\n",
+    "[s[r * d[1] + c] for c in range(d[1])] for r in range(d[0])\n",
+    "for r in range(d[0]):\n",
+    "    l1.append([])\n",
+    "    for c in range(d[1]):\n",
+    "        l1[r].append(s[r * d[1] + c])\n",
+    "for r in l1:\n",
+    "    print(*r, sep=\"\")\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "subslide"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "###   \n",
+      "# #   \n",
+      "###   \n",
+      "#  # #\n",
+      "#   # \n",
+      "#   # \n",
+      "   #  \n"
+     ]
+    }
+   ],
+   "source": [
+    "dimensions = (7, 6); d = dimensions\n",
+    "s = \"111000101000111000100101100010100010000100\"\n",
+    "l1 = [[\"#\" if s[r * d[1] + c] == \"1\"\n",
+    "       else \" \"\n",
+    "       for c in range(d[1])] \n",
+    "      for r in range(d[0])]\n",
+    "for r in l1:\n",
+    "    print(*r, sep=\"\")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {