from math import e, pi, inf, nan, isinf, isnan

from math import log, log10, log2

* **Use `'<D/DT>.weekday()'` to get the day of the week (Mon == 0).**

* **`'fold=1'` means the second pass in case of time jumping back for one hour.**

<list> = next(<reader>) # Returns next row as a list of strings.

<list> = list(<reader>) # Returns list of remaining rows.

<writer> = csv.writer(<file>) # Also: `dialect='excel', delimiter=','`.

<writer>.writerow(<collection>) # Encodes objects using `str(<el>)`.

<writer>.writerows(<coll_of_coll>) # Appends multiple rows.

* **`'dialect'` - Master parameter that sets the default values.**

>>> conn = sqlite3.connect('test.db')

[(1, 'Jean-Luc', 187)]

```

<Exec> = ThreadPoolExecutor(max_workers=None) # Or: `with ThreadPoolExecutor() as <name>: …`

>>> from timeit import timeit

... number=10000, globals=globals(), setup='pass')

<1d_array> = <2d_array>[<2d_bools>]

**Broadcasting is a set of rules by which NumPy functions operate on arrays of different sizes and/or dimensions.**

F = 44100

P1 = '71♩,69♪,,71♩,66♪,,62♩,66♪,,59♩,,,'

P2 = '71♩,73♪,,74♩,73♪,,74♪,,71♪,,73♩,71♪,,73♪,,69♪,,71♩,69♪,,71♪,,67♪,,71♩,,,'

<div><h3 id="math">Math</h3><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> e, pi, inf, nan, isinf, isnan

<span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> log, log10, log2

<li><strong>Use <code class="python hljs"><span class="hljs-string">'&lt;D/DT&gt;.weekday()'</span></code> to get the day of the week (Mon == 0).</strong></li>

<li><strong><code class="python hljs"><span class="hljs-string">'fold=1'</span></code> means the second pass in case of time jumping back for one hour.</strong></li>

<div><h3 id="now">Now</h3><pre><code class="python language-python hljs">&lt;D/DTn&gt; = D/DT.today() <span class="hljs-comment"># Current local date or naive datetime.</span>

&lt;DTn&gt; = DT.utcnow() <span class="hljs-comment"># Naive datetime from current UTC time.</span>

<div><h3 id="write">Write</h3><pre><code class="python language-python hljs">&lt;writer&gt; = csv.writer(&lt;file&gt;) <span class="hljs-comment"># Also: `dialect='excel', delimiter=','`.</span>

&lt;writer&gt;.writerow(&lt;collection&gt;) <span class="hljs-comment"># Encodes objects using `str(&lt;el&gt;)`.</span>

&lt;writer&gt;.writerows(&lt;coll_of_coll&gt;) <span class="hljs-comment"># Appends multiple rows.</span>

<div><h3 id="parameters">Parameters</h3><ul>

<li><strong><code class="python hljs"><span class="hljs-string">'dialect'</span></code> - Master parameter that sets the default values.</strong></li>

<li><strong><code class="python hljs"><span class="hljs-string">'quoting'</span></code> - Controls the amount of quoting: 0 - as necessary, 1 - all.</strong></li>

<li><strong><code class="python hljs"><span class="hljs-string">'escapechar'</span></code> - Character for escaping 'quotechar' if 'doublequote' is False.</strong></li>

</ul><div><h3 id="dialects">Dialects</h3><pre><code class="text language-text">┏━━━━━━━━━━━━━━━━━━┯━━━━━━━━━━━━━━┯━━━━━━━━━━━━━━┯━━━━━━━━━━━━━━┓

┠──────────────────┼──────────────┼──────────────┼──────────────┨

┗━━━━━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━┛

<div><h3 id="example">Example</h3><p><strong>In this example values are not actually saved because <code class="python hljs"><span class="hljs-string">'conn.commit()'</span></code> is omitted!</strong></p><pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>conn = sqlite3.connect(<span class="hljs-string">'test.db'</span>)

<span class="hljs-number">1</span>

[(<span class="hljs-number">1</span>, <span class="hljs-string">'Jean-Luc'</span>, <span class="hljs-number">187</span>)]

<pre><code class="python language-python hljs">&lt;Exec&gt; = ThreadPoolExecutor(max_workers=<span class="hljs-keyword">None</span>) <span class="hljs-comment"># Or: `with ThreadPoolExecutor() as &lt;name&gt;: …`</span>

<pre><code class="python language-python hljs">&lt;iter&gt; = &lt;Exec&gt;.map(&lt;func&gt;, &lt;args_1&gt;, ...) <span class="hljs-comment"># A multithreaded and non-lazy map().</span>

&lt;Futr&gt; = &lt;Exec&gt;.submit(&lt;func&gt;, &lt;arg_1&gt;, ...) <span class="hljs-comment"># Starts a thread and returns its Future object.</span>

<div><h3 id="timingasnippet">Timing a Snippet</h3><pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span><span class="hljs-keyword">from</span> timeit <span class="hljs-keyword">import</span> timeit

<span class="hljs-meta">... </span> number=<span class="hljs-number">10000</span>, globals=globals(), setup=<span class="hljs-string">'pass'</span>)

<span class="hljs-number">0.34986</span>

<li><strong>Shape is a tuple of dimension sizes.</strong></li>

<li><strong>Axis is an index of the dimension that gets collapsed. Leftmost dimension has index 0.</strong></li>

&lt;1d_array&gt; = &lt;2d_array&gt;[&lt;2d_bools&gt;]

<div><h3 id="broadcasting">Broadcasting</h3><p><strong>Broadcasting is a set of rules by which NumPy functions operate on arrays of different sizes and/or dimensions.</strong></p><pre><code class="python language-python hljs">left = [[<span class="hljs-number">0.1</span>], [<span class="hljs-number">0.6</span>], [<span class="hljs-number">0.8</span>]] <span class="hljs-comment"># Shape: (3, 1)</span>

right = [ <span class="hljs-number">0.1</span> , <span class="hljs-number">0.6</span> , <span class="hljs-number">0.8</span> ] <span class="hljs-comment"># Shape: (3)</span>

<div><h2 id="synthesizer"><a href="#synthesizer" name="synthesizer">#</a>Synthesizer</h2><div><h4 id="playspopcornbygershonkingsley">Plays Popcorn by Gershon Kingsley:</h4><pre><code class="python language-python hljs"><span class="hljs-comment"># $ pip3 install simpleaudio</span>

F = <span class="hljs-number">44100</span>

P1 = <span class="hljs-string">'71♩,69♪,,71♩,66♪,,62♩,66♪,,59♩,,,'</span>

P2 = <span class="hljs-string">'71♩,73♪,,74♩,73♪,,74♪,,71♪,,73♩,71♪,,73♪,,69♪,,71♩,69♪,,71♪,,67♪,,71♩,,,'</span>