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python-cheatsheet
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Main, Dictionary, Enumerate

pull/188/head
Jure Šorn 10 months ago
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2 changed files with 14 additions and 15 deletions
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  1. 13
      README.md
  2. 16
      index.html

13
README.md
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@ -21,8 +21,8 @@ Contents
Main
----
```python
if __name__ == '__main__': # Runs main() if file wasn't imported.
main()
if __name__ == '__main__': # Skips next line if file was imported.
main() # Runs `def main(): ...` function.
```
@ -99,9 +99,9 @@ value = <dict>.pop(key) # Removes item or raises KeyErro
### Counter
```python
>>> from collections import Counter
>>> colors = ['blue', 'blue', 'blue', 'red', 'red']
>>> counter = Counter(colors)
>>> counter = Counter(['blue', 'blue', 'blue', 'red', 'red'])
>>> counter['yellow'] += 1
>>> print(counter)
Counter({'blue': 3, 'red': 2, 'yellow': 1})
>>> counter.most_common()[0]
('blue', 3)
@ -153,11 +153,10 @@ Tuple
### Named Tuple
**Tuple's subclass with named elements.**
```python
>>> from collections import namedtuple
>>> Point = namedtuple('Point', 'x y')
>>> p = Point(1, y=2)
>>> p = Point(1, y=2); p
Point(x=1, y=2)
>>> p[0]
1
@ -186,7 +185,7 @@ Range
Enumerate
---------
```python
for i, el in enumerate(<collection> [, i_start]):
for i, el in enumerate(<coll>, start=0): # Returns iterator of `(index+start, <el>)` tuples.
...
```

16
index.html
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@ -54,7 +54,7 @@
<body>
<header>
<aside>June 20, 2024</aside>
<aside>July 7, 2024</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</header>
@ -96,8 +96,8 @@
<div><h2 id="main"><a href="#main" name="main">#</a>Main</h2><pre><code class="python language-python hljs"><span class="hljs-keyword">if</span> __name__ == <span class="hljs-string">'__main__'</span>: <span class="hljs-comment"># Runs main() if file wasn't imported.</span>
main()
<div><h2 id="main"><a href="#main" name="main">#</a>Main</h2><pre><code class="python language-python hljs"><span class="hljs-keyword">if</span> __name__ == <span class="hljs-string">'__main__'</span>: <span class="hljs-comment"># Skips next line if file was imported.</span>
main() <span class="hljs-comment"># Runs `def main(): ...` function.</span>
</code></pre></div>
<div><h2 id="list"><a href="#list" name="list">#</a>List</h2><pre><code class="python language-python hljs">&lt;el&gt; = &lt;list&gt;[index] <span class="hljs-comment"># First index is 0. Last -1. Allows assignments.</span>
@ -152,9 +152,9 @@ value = &lt;dict&gt;.pop(key) <span class="hljs-comment"
{k: v <span class="hljs-keyword">for</span> k, v <span class="hljs-keyword">in</span> &lt;dict&gt;.items() <span class="hljs-keyword">if</span> k <span class="hljs-keyword">in</span> keys} <span class="hljs-comment"># Filters the dictionary by keys.</span>
</code></pre>
<div><h3 id="counter">Counter</h3><pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span><span class="hljs-keyword">from</span> collections <span class="hljs-keyword">import</span> Counter
<span class="hljs-meta">&gt;&gt;&gt; </span>colors = [<span class="hljs-string">'blue'</span>, <span class="hljs-string">'blue'</span>, <span class="hljs-string">'blue'</span>, <span class="hljs-string">'red'</span>, <span class="hljs-string">'red'</span>]
<span class="hljs-meta">&gt;&gt;&gt; </span>counter = Counter(colors)
<span class="hljs-meta">&gt;&gt;&gt; </span>counter = Counter([<span class="hljs-string">'blue'</span>, <span class="hljs-string">'blue'</span>, <span class="hljs-string">'blue'</span>, <span class="hljs-string">'red'</span>, <span class="hljs-string">'red'</span>])
<span class="hljs-meta">&gt;&gt;&gt; </span>counter[<span class="hljs-string">'yellow'</span>] += <span class="hljs-number">1</span>
<span class="hljs-meta">&gt;&gt;&gt; </span>print(counter)
Counter({<span class="hljs-string">'blue'</span>: <span class="hljs-number">3</span>, <span class="hljs-string">'red'</span>: <span class="hljs-number">2</span>, <span class="hljs-string">'yellow'</span>: <span class="hljs-number">1</span>})
<span class="hljs-meta">&gt;&gt;&gt; </span>counter.most_common()[<span class="hljs-number">0</span>]
(<span class="hljs-string">'blue'</span>, <span class="hljs-number">3</span>)
@ -192,7 +192,7 @@ Counter({<span class="hljs-string">'blue'</span>: <span class="hljs-number">3</s
<div><h3 id="namedtuple">Named Tuple</h3><p><strong>Tuple's subclass with named elements.</strong></p><pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span><span class="hljs-keyword">from</span> collections <span class="hljs-keyword">import</span> namedtuple
<span class="hljs-meta">&gt;&gt;&gt; </span>Point = namedtuple(<span class="hljs-string">'Point'</span>, <span class="hljs-string">'x y'</span>)
<span class="hljs-meta">&gt;&gt;&gt; </span>p = Point(<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>)
<span class="hljs-meta">&gt;&gt;&gt; </span>p = Point(<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>); p
Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>)
<span class="hljs-meta">&gt;&gt;&gt; </span>p[<span class="hljs-number">0</span>]
<span class="hljs-number">1</span>
@ -212,7 +212,7 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>[i <span class="hljs-keyword">for</span> i <span class="hljs-keyword">in</span> range(<span class="hljs-number">3</span>)]
[<span class="hljs-number">0</span>, <span class="hljs-number">1</span>, <span class="hljs-number">2</span>]
</code></pre>
<div><h2 id="enumerate"><a href="#enumerate" name="enumerate">#</a>Enumerate</h2><pre><code class="python language-python hljs"><span class="hljs-keyword">for</span> i, el <span class="hljs-keyword">in</span> enumerate(&lt;collection&gt; [, i_start]):
<div><h2 id="enumerate"><a href="#enumerate" name="enumerate">#</a>Enumerate</h2><pre><code class="python language-python hljs"><span class="hljs-keyword">for</span> i, el <span class="hljs-keyword">in</span> enumerate(&lt;coll&gt;, start=<span class="hljs-number">0</span>): <span class="hljs-comment"># Returns iterator of `(index+start, &lt;el&gt;)` tuples.</span>
...
</code></pre></div>
@ -2931,7 +2931,7 @@ $ deactivate <span class="hljs-comment"># Deactivates the activ
<footer>
<aside>June 20, 2024</aside>
<aside>July 7, 2024</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</footer>

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