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python-cheatsheet
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Numbers big changes, Combinatorics, Console app, GUI, Web

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Jure Šorn 2 weeks ago
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  1. 115
      README.md
  2. 115
      index.html
  3. 12
      parse.js
  4. 4
      pdf/index_for_pdf.html

115
README.md
View File

@ -494,64 +494,69 @@ Format
Numbers
-------
```python
<int> = int(<float/str/bool>) # Or: math.trunc(<float>)
<float> = float(<int/str/bool>) # Or: <int/float>e±<int>
<complex> = complex(real=0, imag=0) # Or: <int/float> ± <int/float>j
<Fraction> = fractions.Fraction(0, 1) # Or: Fraction(numerator=0, denominator=1)
<Decimal> = decimal.Decimal(<str/int>) # Or: Decimal((sign, digits, exponent))
<int> = int(<float/str/bool>) # Or: math.trunc(<float>)
<float> = float(<int/str/bool>) # Or: <int/float>e±<int>
<complex> = complex(real=0, imag=0) # Or: <int/float> ± <int/float>j
<Fraction> = fractions.Fraction(0, 1) # Or: Fraction(numerator=0, denominator=1)
<Decimal> = decimal.Decimal(<str/int>) # Or: Decimal((sign, digits, exponent))
```
* **`'int(<str>)'` and `'float(<str>)'` raise ValueError on malformed strings.**
* **Decimal numbers are stored exactly, unlike most floats where `'1.1 + 2.2 != 3.3'`.**
* **Floats can be compared with: `'math.isclose(<float>, <float>)'`.**
* **Precision of decimal operations is set with: `'decimal.getcontext().prec = <int>'`.**
* **Bools can be used anywhere ints can, because bool is a subclass of int: `'True + 1 == 2'`.**
### Basic Functions
### Built-in Functions
```python
<num> = pow(<num>, <num>) # Or: <number> ** <number>
<num> = abs(<num>) # <float> = abs(<complex>)
<num> = round(<num> [, ±ndigits]) # `round(126, -1) == 130`
<num> = pow(<num>, <num>) # Or: <number> ** <number>
<num> = abs(<num>) # <float> = abs(<complex>)
<num> = round(<num> [, ±ndigits]) # Also math.floor/ceil(<number>).
<num> = min(<collection>) # Also max(<num>, <num> [, ...]).
<num> = sum(<collection>) # Also math.prod(<collection>).
```
### Math
```python
from math import e, pi, inf, nan, isinf, isnan # `<el> == nan` is always False.
from math import sin, cos, tan, asin, acos, atan # Also: degrees, radians.
from math import log, log10, log2 # Log can accept base as second arg.
from math import e, pi, inf, nan, isnan # `inf*0` and `nan+1` return nan.
from math import sqrt, factorial # `sqrt(-1)` raises ValueError.
from math import sin, cos, tan # Also: asin, degrees, radians.
from math import log, log10, log2 # Log accepts base as second arg.
```
### Statistics
```python
from statistics import mean, median, variance # Also: stdev, quantiles, groupby.
from statistics import mean, median, mode # Mode returns the most common value.
from statistics import variance, stdev # Also: pvariance, pstdev, quantiles.
```
### Random
```python
from random import random, randint, uniform # Also: gauss, choice, shuffle, seed.
from random import random, randint, uniform # Also: gauss, choice, shuffle, seed.
```
```python
<float> = random() # Returns a float inside [0, 1).
<num> = randint/uniform(a, b) # Returns an int/float inside [a, b].
<float> = gauss(mean, stdev) # Also triangular(low, high, mode).
<el> = choice(<sequence>) # Keeps it intact. Also sample(pop, k).
shuffle(<list>) # Shuffles the list in place.
<float> = random() # Returns a float inside [0, 1).
<num> = randint/uniform(a, b) # Returns an int/float inside [a, b].
<float> = gauss(mean, stdev) # Also triangular(low, high, mode).
<el> = choice(<sequence>) # Keeps it intact. Also sample(pop, k).
shuffle(<list>) # Shuffles the list in place.
```
### Hexadecimal Numbers
```python
<int> = ±0x<hex> # Or: ±0b<bin>
<int> = int('±<hex>', 16) # Or: int('±<bin>', 2)
<int> = int('±0x<hex>', 0) # Or: int('±0b<bin>', 0)
<str> = hex(<int>) # Returns '[-]0x<hex>'. Also bin().
<int> = ±0x<hex> # Or: ±0b<bin>
<int> = int('±<hex>', 16) # Or: int('±<bin>', 2)
<int> = int('±0x<hex>', 0) # Or: int('±0b<bin>', 0)
<str> = hex(<int>) # Returns '[-]0x<hex>'. Also bin().
```
### Bitwise Operators
```python
<int> = <int> & <int> # And (0b1100 & 0b1010 == 0b1000).
<int> = <int> | <int> # Or (0b1100 | 0b1010 == 0b1110).
<int> = <int> ^ <int> # Xor (0b1100 ^ 0b1010 == 0b0110).
<int> = <int> << n_bits # Left shift. Use >> for right.
<int> = ~<int> # Not. Also -<int> - 1.
<int> = <int> & <int> # And (0b1100 & 0b1010 == 0b1000).
<int> = <int> | <int> # Or (0b1100 | 0b1010 == 0b1110).
<int> = <int> ^ <int> # Xor (0b1100 ^ 0b1010 == 0b0110).
<int> = <int> << n_bits # Left shift. Use >> for right.
<int> = ~<int> # Not. Also -<int> - 1.
```
@ -562,30 +567,24 @@ import itertools as it
```
```python
>>> list(it.product([0, 1], repeat=3))
[(0, 0, 0), (0, 0, 1), (0, 1, 0), (0, 1, 1),
(1, 0, 0), (1, 0, 1), (1, 1, 0), (1, 1, 1)]
>>> list(it.product('abc', repeat=2)) # a b c
[('a', 'a'), ('a', 'b'), ('a', 'c'), # a x x x
('b', 'a'), ('b', 'b'), ('b', 'c'), # b x x x
('c', 'a'), ('c', 'b'), ('c', 'c')] # c x x x
```
```python
>>> list(it.product('abc', 'abc')) # a b c
[('a', 'a'), ('a', 'b'), ('a', 'c'), # a x x x
('b', 'a'), ('b', 'b'), ('b', 'c'), # b x x x
('c', 'a'), ('c', 'b'), ('c', 'c')] # c x x x
>>> list(it.permutations('abc', 2)) # a b c
[('a', 'b'), ('a', 'c'), # a . x x
('b', 'a'), ('b', 'c'), # b x . x
('c', 'a'), ('c', 'b')] # c x x .
```
```python
>>> list(it.permutations('abc', 2)) # a b c
[('a', 'b'), ('a', 'c'), # a . x x
('b', 'a'), ('b', 'c'), # b x . x
('c', 'a'), ('c', 'b')] # c x x .
```
```python
>>> list(it.combinations('abc', 2)) # a b c
[('a', 'b'), ('a', 'c'), # a . x x
('b', 'c'), # b . . x
] # c . . .
>>> list(it.combinations('abc', 2)) # a b c
[('a', 'b'), ('a', 'c'), # a . x x
('b', 'c'), # b . . x
] # c . . .
```
@ -1183,7 +1182,7 @@ class Counter:
### Callable
* **All functions and classes have a call() method, hence are callable.**
* **Use `'callable(<obj>)'` or `'isinstance(<obj>, collections.abc.Callable)'` to check if object is callable.**
* **Use `'callable(<obj>)'` or `'isinstance(<obj>, collections.abc.Callable)'` to check if object is callable. Calling an uncallable object raises `'TypeError'`.**
* **When this cheatsheet uses `'<function>'` as an argument, it means `'<callable>'`.**
```python
class Counter:
@ -2435,7 +2434,7 @@ Console App
```python
# $ pip3 install windows-curses
import curses, os
from curses import A_REVERSE, KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT, KEY_ENTER
from curses import A_REVERSE, KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT
def main(screen):
ch, first, selected, paths = 0, 0, 0, os.listdir()
@ -2450,7 +2449,7 @@ def main(screen):
selected += (ch == KEY_DOWN) and (selected < len(paths)-1)
first -= (first > selected)
first += (first < selected-(height-1))
if ch in [KEY_LEFT, KEY_RIGHT, KEY_ENTER, ord('\n'), ord('\r')]:
if ch in [KEY_LEFT, KEY_RIGHT, ord('\n')]:
new_dir = '..' if ch == KEY_LEFT else paths[selected]
if os.path.isdir(new_dir):
os.chdir(new_dir)
@ -2469,9 +2468,9 @@ GUI App
# $ pip3 install PySimpleGUI
import PySimpleGUI as sg
text_box = sg.Input(default_text='100', enable_events=True, key='-QUANTITY-')
dropdown = sg.InputCombo(['g', 'kg', 't'], 'kg', readonly=True, enable_events=True, k='-UNIT-')
label = sg.Text('100 kg is 220.462 lbs.', key='-OUTPUT-')
text_box = sg.Input(default_text='100', enable_events=True, key='QUANTITY')
dropdown = sg.InputCombo(['g', 'kg', 't'], 'kg', readonly=True, enable_events=True, k='UNIT')
label = sg.Text('100 kg is 220.462 lbs.', key='OUTPUT')
button = sg.Button('Close')
window = sg.Window('Weight Converter', [[text_box, dropdown], [label], [button]])
@ -2480,13 +2479,13 @@ while True:
if event in [sg.WIN_CLOSED, 'Close']:
break
try:
quantity = float(values['-QUANTITY-'])
quantity = float(values['QUANTITY'])
except ValueError:
continue
unit = values['-UNIT-']
unit = values['UNIT']
factors = {'g': 0.001, 'kg': 1, 't': 1000}
lbs = quantity * factors[unit] / 0.45359237
window['-OUTPUT-'].update(value=f'{quantity} {unit} is {lbs:g} lbs.')
window['OUTPUT'].update(value=f'{quantity} {unit} is {lbs:g} lbs.')
window.close()
```
@ -2552,14 +2551,14 @@ app.run(host=None, port=None, debug=None) # Or: $ flask --app FILE run [--ARG[=
* **Install a WSGI server like [Waitress](https://flask.palletsprojects.com/en/latest/deploying/waitress/) and a HTTP server such as [Nginx](https://flask.palletsprojects.com/en/latest/deploying/nginx/) for better security.**
* **Debug mode restarts the app whenever script changes and displays errors in the browser.**
### Static Request
### Serving Files
```python
@app.route('/img/<path:filename>')
def serve_file(filename):
return fl.send_from_directory('DIRNAME', filename)
```
### Dynamic Request
### Serving HTML
```python
@app.route('/<sport>')
def serve_html(sport):
@ -2570,7 +2569,7 @@ def serve_html(sport):
* **`'fl.request.args[<str>]'` returns parameter from query string (URL part right of '?').**
* **`'fl.session[<str>] = <obj>'` stores session data. It requires secret key to be set at the startup with `'app.secret_key = <str>'`.**
### REST Request
### Serving JSON
```python
@app.post('/<sport>/odds')
def serve_json(sport):

115
index.html
View File

@ -56,7 +56,7 @@
<body>
<header>
<aside>April 17, 2025</aside>
<aside>April 22, 2025</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</header>
@ -455,75 +455,76 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
{<span class="hljs-number">90</span>:X} <span class="hljs-comment"># '5A'. Hexadecimal with upper-case letters.</span>
</code></pre></div>
<div><h2 id="numbers"><a href="#numbers" name="numbers">#</a>Numbers</h2><pre><code class="python language-python hljs">&lt;int&gt; = int(&lt;float/str/bool&gt;) <span class="hljs-comment"># Or: math.trunc(&lt;float&gt;)</span>
&lt;float&gt; = float(&lt;int/str/bool&gt;) <span class="hljs-comment"># Or: &lt;int/float&gt;e±&lt;int&gt;</span>
&lt;complex&gt; = complex(real=<span class="hljs-number">0</span>, imag=<span class="hljs-number">0</span>) <span class="hljs-comment"># Or: &lt;int/float&gt; ± &lt;int/float&gt;j</span>
&lt;Fraction&gt; = fractions.Fraction(<span class="hljs-number">0</span>, <span class="hljs-number">1</span>) <span class="hljs-comment"># Or: Fraction(numerator=0, denominator=1)</span>
&lt;Decimal&gt; = decimal.Decimal(&lt;str/int&gt;) <span class="hljs-comment"># Or: Decimal((sign, digits, exponent))</span>
<div><h2 id="numbers"><a href="#numbers" name="numbers">#</a>Numbers</h2><pre><code class="python language-python hljs">&lt;int&gt; = int(&lt;float/str/bool&gt;) <span class="hljs-comment"># Or: math.trunc(&lt;float&gt;)</span>
&lt;float&gt; = float(&lt;int/str/bool&gt;) <span class="hljs-comment"># Or: &lt;int/float&gt;e±&lt;int&gt;</span>
&lt;complex&gt; = complex(real=<span class="hljs-number">0</span>, imag=<span class="hljs-number">0</span>) <span class="hljs-comment"># Or: &lt;int/float&gt; ± &lt;int/float&gt;j</span>
&lt;Fraction&gt; = fractions.Fraction(<span class="hljs-number">0</span>, <span class="hljs-number">1</span>) <span class="hljs-comment"># Or: Fraction(numerator=0, denominator=1)</span>
&lt;Decimal&gt; = decimal.Decimal(&lt;str/int&gt;) <span class="hljs-comment"># Or: Decimal((sign, digits, exponent))</span>
</code></pre></div>
<ul>
<li><strong><code class="python hljs"><span class="hljs-string">'int(&lt;str&gt;)'</span></code> and <code class="python hljs"><span class="hljs-string">'float(&lt;str&gt;)'</span></code> raise ValueError on malformed strings.</strong></li>
<li><strong>Decimal numbers are stored exactly, unlike most floats where <code class="python hljs"><span class="hljs-string">'1.1 + 2.2 != 3.3'</span></code>.</strong></li>
<li><strong>Floats can be compared with: <code class="python hljs"><span class="hljs-string">'math.isclose(&lt;float&gt;, &lt;float&gt;)'</span></code>.</strong></li>
<li><strong>Precision of decimal operations is set with: <code class="python hljs"><span class="hljs-string">'decimal.getcontext().prec = &lt;int&gt;'</span></code>.</strong></li>
<li><strong>Bools can be used anywhere ints can, because bool is a subclass of int: <code class="python hljs"><span class="hljs-string">'True + 1 == 2'</span></code>.</strong></li>
</ul>
<div><h3 id="basicfunctions">Basic Functions</h3><pre><code class="python language-python hljs">&lt;num&gt; = pow(&lt;num&gt;, &lt;num&gt;) <span class="hljs-comment"># Or: &lt;number&gt; ** &lt;number&gt;</span>
&lt;num&gt; = abs(&lt;num&gt;) <span class="hljs-comment"># &lt;float&gt; = abs(&lt;complex&gt;)</span>
&lt;num&gt; = round(&lt;num&gt; [, ±ndigits]) <span class="hljs-comment"># `round(126, -1) == 130`</span>
<div><h3 id="builtinfunctions">Built-in Functions</h3><pre><code class="python language-python hljs">&lt;num&gt; = pow(&lt;num&gt;, &lt;num&gt;) <span class="hljs-comment"># Or: &lt;number&gt; ** &lt;number&gt;</span>
&lt;num&gt; = abs(&lt;num&gt;) <span class="hljs-comment"># &lt;float&gt; = abs(&lt;complex&gt;)</span>
&lt;num&gt; = round(&lt;num&gt; [, ±ndigits]) <span class="hljs-comment"># Also math.floor/ceil(&lt;number&gt;).</span>
&lt;num&gt; = min(&lt;collection&gt;) <span class="hljs-comment"># Also max(&lt;num&gt;, &lt;num&gt; [, ...]).</span>
&lt;num&gt; = sum(&lt;collection&gt;) <span class="hljs-comment"># Also math.prod(&lt;collection&gt;).</span>
</code></pre></div>
<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-comment"># `&lt;el&gt; == nan` is always False.</span>
<span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> sin, cos, tan, asin, acos, atan <span class="hljs-comment"># Also: degrees, radians.</span>
<span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> log, log10, log2 <span class="hljs-comment"># Log can accept base as second arg.</span>
<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, isnan <span class="hljs-comment"># `inf*0` and `nan+1` return nan.</span>
<span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> sqrt, factorial <span class="hljs-comment"># `sqrt(-1)` raises ValueError.</span>
<span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> sin, cos, tan <span class="hljs-comment"># Also: asin, degrees, radians.</span>
<span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> log, log10, log2 <span class="hljs-comment"># Log accepts base as second arg.</span>
</code></pre></div>
<div><h3 id="statistics">Statistics</h3><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> statistics <span class="hljs-keyword">import</span> mean, median, variance <span class="hljs-comment"># Also: stdev, quantiles, groupby.</span>
<div><h3 id="statistics">Statistics</h3><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> statistics <span class="hljs-keyword">import</span> mean, median, mode <span class="hljs-comment"># Mode returns the most common value.</span>
<span class="hljs-keyword">from</span> statistics <span class="hljs-keyword">import</span> variance, stdev <span class="hljs-comment"># Also: pvariance, pstdev, quantiles.</span>
</code></pre></div>
<div><h3 id="random">Random</h3><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> random <span class="hljs-keyword">import</span> random, randint, uniform <span class="hljs-comment"># Also: gauss, choice, shuffle, seed.</span>
<div><h3 id="random">Random</h3><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> random <span class="hljs-keyword">import</span> random, randint, uniform <span class="hljs-comment"># Also: gauss, choice, shuffle, seed.</span>
</code></pre></div>
<pre><code class="python language-python hljs">&lt;float&gt; = random() <span class="hljs-comment"># Returns a float inside [0, 1).</span>
&lt;num&gt; = randint/uniform(a, b) <span class="hljs-comment"># Returns an int/float inside [a, b].</span>
&lt;float&gt; = gauss(mean, stdev) <span class="hljs-comment"># Also triangular(low, high, mode).</span>
&lt;el&gt; = choice(&lt;sequence&gt;) <span class="hljs-comment"># Keeps it intact. Also sample(pop, k).</span>
shuffle(&lt;list&gt;) <span class="hljs-comment"># Shuffles the list in place.</span>
<pre><code class="python language-python hljs">&lt;float&gt; = random() <span class="hljs-comment"># Returns a float inside [0, 1).</span>
&lt;num&gt; = randint/uniform(a, b) <span class="hljs-comment"># Returns an int/float inside [a, b].</span>
&lt;float&gt; = gauss(mean, stdev) <span class="hljs-comment"># Also triangular(low, high, mode).</span>
&lt;el&gt; = choice(&lt;sequence&gt;) <span class="hljs-comment"># Keeps it intact. Also sample(pop, k).</span>
shuffle(&lt;list&gt;) <span class="hljs-comment"># Shuffles the list in place.</span>
</code></pre>
<div><h3 id="hexadecimalnumbers">Hexadecimal Numbers</h3><pre><code class="python language-python hljs">&lt;int&gt; = ±<span class="hljs-number">0x</span>&lt;hex&gt; <span class="hljs-comment"># Or: ±0b&lt;bin&gt;</span>
&lt;int&gt; = int(<span class="hljs-string">'±&lt;hex&gt;'</span>, <span class="hljs-number">16</span>) <span class="hljs-comment"># Or: int('±&lt;bin&gt;', 2)</span>
&lt;int&gt; = int(<span class="hljs-string">'±0x&lt;hex&gt;'</span>, <span class="hljs-number">0</span>) <span class="hljs-comment"># Or: int('±0b&lt;bin&gt;', 0)</span>
&lt;str&gt; = hex(&lt;int&gt;) <span class="hljs-comment"># Returns '[-]0x&lt;hex&gt;'. Also bin().</span>
<div><h3 id="hexadecimalnumbers">Hexadecimal Numbers</h3><pre><code class="python language-python hljs">&lt;int&gt; = ±<span class="hljs-number">0x</span>&lt;hex&gt; <span class="hljs-comment"># Or: ±0b&lt;bin&gt;</span>
&lt;int&gt; = int(<span class="hljs-string">'±&lt;hex&gt;'</span>, <span class="hljs-number">16</span>) <span class="hljs-comment"># Or: int('±&lt;bin&gt;', 2)</span>
&lt;int&gt; = int(<span class="hljs-string">'±0x&lt;hex&gt;'</span>, <span class="hljs-number">0</span>) <span class="hljs-comment"># Or: int('±0b&lt;bin&gt;', 0)</span>
&lt;str&gt; = hex(&lt;int&gt;) <span class="hljs-comment"># Returns '[-]0x&lt;hex&gt;'. Also bin().</span>
</code></pre></div>
<div><h3 id="bitwiseoperators">Bitwise Operators</h3><pre><code class="python language-python hljs">&lt;int&gt; = &lt;int&gt; &amp; &lt;int&gt; <span class="hljs-comment"># And (0b1100 &amp; 0b1010 == 0b1000).</span>
&lt;int&gt; = &lt;int&gt; | &lt;int&gt; <span class="hljs-comment"># Or (0b1100 | 0b1010 == 0b1110).</span>
&lt;int&gt; = &lt;int&gt; ^ &lt;int&gt; <span class="hljs-comment"># Xor (0b1100 ^ 0b1010 == 0b0110).</span>
&lt;int&gt; = &lt;int&gt; &lt;&lt; n_bits <span class="hljs-comment"># Left shift. Use &gt;&gt; for right.</span>
&lt;int&gt; = ~&lt;int&gt; <span class="hljs-comment"># Not. Also -&lt;int&gt; - 1.</span>
<div><h3 id="bitwiseoperators">Bitwise Operators</h3><pre><code class="python language-python hljs">&lt;int&gt; = &lt;int&gt; &amp; &lt;int&gt; <span class="hljs-comment"># And (0b1100 &amp; 0b1010 == 0b1000).</span>
&lt;int&gt; = &lt;int&gt; | &lt;int&gt; <span class="hljs-comment"># Or (0b1100 | 0b1010 == 0b1110).</span>
&lt;int&gt; = &lt;int&gt; ^ &lt;int&gt; <span class="hljs-comment"># Xor (0b1100 ^ 0b1010 == 0b0110).</span>
&lt;int&gt; = &lt;int&gt; &lt;&lt; n_bits <span class="hljs-comment"># Left shift. Use &gt;&gt; for right.</span>
&lt;int&gt; = ~&lt;int&gt; <span class="hljs-comment"># Not. Also -&lt;int&gt; - 1.</span>
</code></pre></div>
<div><h2 id="combinatorics"><a href="#combinatorics" name="combinatorics">#</a>Combinatorics</h2><pre><code class="python language-python hljs"><span class="hljs-keyword">import</span> itertools <span class="hljs-keyword">as</span> it
</code></pre></div>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.product([<span class="hljs-number">0</span>, <span class="hljs-number">1</span>], repeat=<span class="hljs-number">3</span>))
[(<span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">1</span>), (<span class="hljs-number">0</span>, <span class="hljs-number">1</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">0</span>, <span class="hljs-number">1</span>, <span class="hljs-number">1</span>),
(<span class="hljs-number">1</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">1</span>, <span class="hljs-number">0</span>, <span class="hljs-number">1</span>), (<span class="hljs-number">1</span>, <span class="hljs-number">1</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">1</span>, <span class="hljs-number">1</span>, <span class="hljs-number">1</span>)]
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.product(<span class="hljs-string">'abc'</span>, repeat=<span class="hljs-number">2</span>)) <span class="hljs-comment"># a b c</span>
[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># a x x x</span>
(<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># b x x x</span>
(<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'c'</span>)] <span class="hljs-comment"># c x x x</span>
</code></pre>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.product(<span class="hljs-string">'abc'</span>, <span class="hljs-string">'abc'</span>)) <span class="hljs-comment"># a b c</span>
[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># a x x x</span>
(<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># b x x x</span>
(<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'c'</span>)] <span class="hljs-comment"># c x x x</span>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.permutations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>)) <span class="hljs-comment"># a b c</span>
[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># a . x x</span>
(<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># b x . x</span>
(<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>)] <span class="hljs-comment"># c x x .</span>
</code></pre>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.permutations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>)) <span class="hljs-comment"># a b c</span>
[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># a . x x</span>
(<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># b x . x</span>
(<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>)] <span class="hljs-comment"># c x x .</span>
</code></pre>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.combinations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>)) <span class="hljs-comment"># a b c</span>
[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># a . x x</span>
(<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># b . . x</span>
] <span class="hljs-comment"># c . . .</span>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.combinations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>)) <span class="hljs-comment"># a b c</span>
[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># a . x x</span>
(<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>), <span class="hljs-comment"># b . . x</span>
] <span class="hljs-comment"># c . . .</span>
</code></pre>
<div><h2 id="datetime"><a href="#datetime" name="datetime">#</a>Datetime</h2><p><strong>Provides 'date', 'time', 'datetime' and 'timedelta' classes. All are immutable and hashable.</strong></p><pre><code class="python language-python hljs"><span class="hljs-comment"># $ pip3 install python-dateutil</span>
<span class="hljs-keyword">from</span> datetime <span class="hljs-keyword">import</span> date, time, datetime, timedelta, timezone
@ -1012,7 +1013,7 @@ P = make_dataclass(<span class="hljs-string">'P'</span>, [(<span class="hljs-str
<li><strong>File objects returned by the <a href="#open">open()</a> function, etc.</strong></li>
</ul><div><h3 id="callable">Callable</h3><ul>
<li><strong>All functions and classes have a call() method, hence are callable.</strong></li>
<li><strong>Use <code class="python hljs"><span class="hljs-string">'callable(&lt;obj&gt;)'</span></code> or <code class="python hljs"><span class="hljs-string">'isinstance(&lt;obj&gt;, collections.abc.Callable)'</span></code> to check if object is callable.</strong></li>
<li><strong>Use <code class="python hljs"><span class="hljs-string">'callable(&lt;obj&gt;)'</span></code> or <code class="python hljs"><span class="hljs-string">'isinstance(&lt;obj&gt;, collections.abc.Callable)'</span></code> to check if object is callable. Calling an uncallable object raises <code class="python hljs"><span class="hljs-string">'TypeError'</span></code>.</strong></li>
<li><strong>When this cheatsheet uses <code class="python hljs"><span class="hljs-string">'&lt;function&gt;'</span></code> as an argument, it means <code class="python hljs"><span class="hljs-string">'&lt;callable&gt;'</span></code>.</strong></li>
</ul><pre><code class="python language-python hljs"><span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Counter</span>:</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">__init__</span><span class="hljs-params">(self)</span>:</span>
@ -2004,7 +2005,7 @@ print(tabulate.tabulate(rows, headers=<span class="hljs-string">'firstrow'</span
<div><h2 id="consoleapp"><a href="#consoleapp" name="consoleapp">#</a>Console App</h2><div><h4 id="runsabasicfileexplorerintheconsole">Runs a basic file explorer in the console:</h4><pre><code class="python language-python hljs"><span class="hljs-comment"># $ pip3 install windows-curses</span>
<span class="hljs-keyword">import</span> curses, os
<span class="hljs-keyword">from</span> curses <span class="hljs-keyword">import</span> A_REVERSE, KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT, KEY_ENTER
<span class="hljs-keyword">from</span> curses <span class="hljs-keyword">import</span> A_REVERSE, KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">main</span><span class="hljs-params">(screen)</span>:</span>
ch, first, selected, paths = <span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>, os.listdir()
@ -2019,7 +2020,7 @@ print(tabulate.tabulate(rows, headers=<span class="hljs-string">'firstrow'</span
selected += (ch == KEY_DOWN) <span class="hljs-keyword">and</span> (selected &lt; len(paths)-<span class="hljs-number">1</span>)
first -= (first &gt; selected)
first += (first &lt; selected-(height-<span class="hljs-number">1</span>))
<span class="hljs-keyword">if</span> ch <span class="hljs-keyword">in</span> [KEY_LEFT, KEY_RIGHT, KEY_ENTER, ord(<span class="hljs-string">'\n'</span>), ord(<span class="hljs-string">'\r'</span>)]:
<span class="hljs-keyword">if</span> ch <span class="hljs-keyword">in</span> [KEY_LEFT, KEY_RIGHT, ord(<span class="hljs-string">'\n'</span>)]:
new_dir = <span class="hljs-string">'..'</span> <span class="hljs-keyword">if</span> ch == KEY_LEFT <span class="hljs-keyword">else</span> paths[selected]
<span class="hljs-keyword">if</span> os.path.isdir(new_dir):
os.chdir(new_dir)
@ -2033,9 +2034,9 @@ print(tabulate.tabulate(rows, headers=<span class="hljs-string">'firstrow'</span
<div><h2 id="guiapp"><a href="#guiapp" name="guiapp">#</a>GUI App</h2><div><h4 id="aweightconverterguiapplication">A weight converter GUI application:</h4><pre><code class="python language-python hljs"><span class="hljs-comment"># $ pip3 install PySimpleGUI</span>
<span class="hljs-keyword">import</span> PySimpleGUI <span class="hljs-keyword">as</span> sg
text_box = sg.Input(default_text=<span class="hljs-string">'100'</span>, enable_events=<span class="hljs-keyword">True</span>, key=<span class="hljs-string">'-QUANTITY-'</span>)
dropdown = sg.InputCombo([<span class="hljs-string">'g'</span>, <span class="hljs-string">'kg'</span>, <span class="hljs-string">'t'</span>], <span class="hljs-string">'kg'</span>, readonly=<span class="hljs-keyword">True</span>, enable_events=<span class="hljs-keyword">True</span>, k=<span class="hljs-string">'-UNIT-'</span>)
label = sg.Text(<span class="hljs-string">'100 kg is 220.462 lbs.'</span>, key=<span class="hljs-string">'-OUTPUT-'</span>)
text_box = sg.Input(default_text=<span class="hljs-string">'100'</span>, enable_events=<span class="hljs-keyword">True</span>, key=<span class="hljs-string">'QUANTITY'</span>)
dropdown = sg.InputCombo([<span class="hljs-string">'g'</span>, <span class="hljs-string">'kg'</span>, <span class="hljs-string">'t'</span>], <span class="hljs-string">'kg'</span>, readonly=<span class="hljs-keyword">True</span>, enable_events=<span class="hljs-keyword">True</span>, k=<span class="hljs-string">'UNIT'</span>)
label = sg.Text(<span class="hljs-string">'100 kg is 220.462 lbs.'</span>, key=<span class="hljs-string">'OUTPUT'</span>)
button = sg.Button(<span class="hljs-string">'Close'</span>)
window = sg.Window(<span class="hljs-string">'Weight Converter'</span>, [[text_box, dropdown], [label], [button]])
@ -2044,13 +2045,13 @@ window = sg.Window(<span class="hljs-string">'Weight Converter'</span>, [[text
<span class="hljs-keyword">if</span> event <span class="hljs-keyword">in</span> [sg.WIN_CLOSED, <span class="hljs-string">'Close'</span>]:
<span class="hljs-keyword">break</span>
<span class="hljs-keyword">try</span>:
quantity = float(values[<span class="hljs-string">'-QUANTITY-'</span>])
quantity = float(values[<span class="hljs-string">'QUANTITY'</span>])
<span class="hljs-keyword">except</span> ValueError:
<span class="hljs-keyword">continue</span>
unit = values[<span class="hljs-string">'-UNIT-'</span>]
unit = values[<span class="hljs-string">'UNIT'</span>]
factors = {<span class="hljs-string">'g'</span>: <span class="hljs-number">0.001</span>, <span class="hljs-string">'kg'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'t'</span>: <span class="hljs-number">1000</span>}
lbs = quantity * factors[unit] / <span class="hljs-number">0.45359237</span>
window[<span class="hljs-string">'-OUTPUT-'</span>].update(value=<span class="hljs-string">f'<span class="hljs-subst">{quantity}</span> <span class="hljs-subst">{unit}</span> is <span class="hljs-subst">{lbs:g}</span> lbs.'</span>)
window[<span class="hljs-string">'OUTPUT'</span>].update(value=<span class="hljs-string">f'<span class="hljs-subst">{quantity}</span> <span class="hljs-subst">{unit}</span> is <span class="hljs-subst">{lbs:g}</span> lbs.'</span>)
window.close()
</code></pre></div></div>
@ -2105,12 +2106,12 @@ app.run(host=<span class="hljs-keyword">None</span>, port=<span class="hljs-keyw
<li><strong>Install a WSGI server like <a href="https://flask.palletsprojects.com/en/latest/deploying/waitress/">Waitress</a> and a HTTP server such as <a href="https://flask.palletsprojects.com/en/latest/deploying/nginx/">Nginx</a> for better security.</strong></li>
<li><strong>Debug mode restarts the app whenever script changes and displays errors in the browser.</strong></li>
</ul>
<div><h3 id="staticrequest">Static Request</h3><pre><code class="python language-python hljs"><span class="hljs-meta">@app.route('/img/&lt;path:filename&gt;')</span>
<div><h3 id="servingfiles">Serving Files</h3><pre><code class="python language-python hljs"><span class="hljs-meta">@app.route('/img/&lt;path:filename&gt;')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">serve_file</span><span class="hljs-params">(filename)</span>:</span>
<span class="hljs-keyword">return</span> fl.send_from_directory(<span class="hljs-string">'DIRNAME'</span>, filename)
</code></pre></div>
<div><h3 id="dynamicrequest">Dynamic Request</h3><pre><code class="python language-python hljs"><span class="hljs-meta">@app.route('/&lt;sport&gt;')</span>
<div><h3 id="servinghtml">Serving HTML</h3><pre><code class="python language-python hljs"><span class="hljs-meta">@app.route('/&lt;sport&gt;')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">serve_html</span><span class="hljs-params">(sport)</span>:</span>
<span class="hljs-keyword">return</span> fl.render_template_string(<span class="hljs-string">'&lt;h1&gt;{{title}}&lt;/h1&gt;'</span>, title=sport)
</code></pre></div>
@ -2121,7 +2122,7 @@ app.run(host=<span class="hljs-keyword">None</span>, port=<span class="hljs-keyw
<li><strong><code class="python hljs"><span class="hljs-string">'fl.request.args[&lt;str&gt;]'</span></code> returns parameter from query string (URL part right of '?').</strong></li>
<li><strong><code class="python hljs"><span class="hljs-string">'fl.session[&lt;str&gt;] = &lt;obj&gt;'</span></code> stores session data. It requires secret key to be set at the startup with <code class="python hljs"><span class="hljs-string">'app.secret_key = &lt;str&gt;'</span></code>.</strong></li>
</ul>
<div><h3 id="restrequest">REST Request</h3><pre><code class="python language-python hljs"><span class="hljs-meta">@app.post('/&lt;sport&gt;/odds')</span>
<div><h3 id="servingjson">Serving JSON</h3><pre><code class="python language-python hljs"><span class="hljs-meta">@app.post('/&lt;sport&gt;/odds')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">serve_json</span><span class="hljs-params">(sport)</span>:</span>
team = fl.request.form[<span class="hljs-string">'team'</span>]
<span class="hljs-keyword">return</span> {<span class="hljs-string">'team'</span>: team, <span class="hljs-string">'odds'</span>: [<span class="hljs-number">2.09</span>, <span class="hljs-number">3.74</span>, <span class="hljs-number">3.68</span>]}
@ -2943,7 +2944,7 @@ $ deactivate <span class="hljs-comment"># Deactivates the active
<footer>
<aside>April 17, 2025</aside>
<aside>April 22, 2025</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</footer>

12
parse.js
View File

@ -43,10 +43,10 @@ const TOC =
'</code></pre>\n';
const BIN_HEX =
'&lt;int&gt; = ±<span class="hljs-number">0x</span>&lt;hex&gt; <span class="hljs-comment"># Or: ±0b&lt;bin&gt;</span>\n' +
'&lt;int&gt; = int(<span class="hljs-string">\'±&lt;hex&gt;\'</span>, <span class="hljs-number">16</span>) <span class="hljs-comment"># Or: int(\'±&lt;bin&gt;\', 2)</span>\n' +
'&lt;int&gt; = int(<span class="hljs-string">\'±0x&lt;hex&gt;\'</span>, <span class="hljs-number">0</span>) <span class="hljs-comment"># Or: int(\'±0b&lt;bin&gt;\', 0)</span>\n' +
'&lt;str&gt; = hex(&lt;int&gt;) <span class="hljs-comment"># Returns \'[-]0x&lt;hex&gt;\'. Also bin().</span>\n';
'&lt;int&gt; = ±<span class="hljs-number">0x</span>&lt;hex&gt; <span class="hljs-comment"># Or: ±0b&lt;bin&gt;</span>\n' +
'&lt;int&gt; = int(<span class="hljs-string">\'±&lt;hex&gt;\'</span>, <span class="hljs-number">16</span>) <span class="hljs-comment"># Or: int(\'±&lt;bin&gt;\', 2)</span>\n' +
'&lt;int&gt; = int(<span class="hljs-string">\'±0x&lt;hex&gt;\'</span>, <span class="hljs-number">0</span>) <span class="hljs-comment"># Or: int(\'±0b&lt;bin&gt;\', 0)</span>\n' +
'&lt;str&gt; = hex(&lt;int&gt;) <span class="hljs-comment"># Returns \'[-]0x&lt;hex&gt;\'. Also bin().</span>\n';
const CACHE =
'<span class="hljs-keyword">from</span> functools <span class="hljs-keyword">import</span> cache\n' +
@ -175,7 +175,7 @@ const COROUTINES =
const CURSES =
'<span class="hljs-comment"># $ pip3 install windows-curses</span>\n' +
'<span class="hljs-keyword">import</span> curses, os\n' +
'<span class="hljs-keyword">from</span> curses <span class="hljs-keyword">import</span> A_REVERSE, KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT, KEY_ENTER\n' +
'<span class="hljs-keyword">from</span> curses <span class="hljs-keyword">import</span> A_REVERSE, KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT\n' +
'\n' +
'<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">main</span><span class="hljs-params">(screen)</span>:</span>\n' +
' ch, first, selected, paths = <span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>, os.listdir()\n' +
@ -190,7 +190,7 @@ const CURSES =
' selected += (ch == KEY_DOWN) <span class="hljs-keyword">and</span> (selected &lt; len(paths)-<span class="hljs-number">1</span>)\n' +
' first -= (first &gt; selected)\n' +
' first += (first &lt; selected-(height-<span class="hljs-number">1</span>))\n' +
' <span class="hljs-keyword">if</span> ch <span class="hljs-keyword">in</span> [KEY_LEFT, KEY_RIGHT, KEY_ENTER, ord(<span class="hljs-string">\'\\n\'</span>), ord(<span class="hljs-string">\'\\r\'</span>)]:\n' +
' <span class="hljs-keyword">if</span> ch <span class="hljs-keyword">in</span> [KEY_LEFT, KEY_RIGHT, ord(<span class="hljs-string">\'\\n\'</span>)]:\n' +
' new_dir = <span class="hljs-string">\'..\'</span> <span class="hljs-keyword">if</span> ch == KEY_LEFT <span class="hljs-keyword">else</span> paths[selected]\n' +
' <span class="hljs-keyword">if</span> os.path.isdir(new_dir):\n' +
' os.chdir(new_dir)\n' +

4
pdf/index_for_pdf.html
View File

@ -73,7 +73,7 @@
<strong>iterator, <a href="#enumerate">3</a>-<a href="#generator">4</a>, <a href="#comprehensions">11</a>, <a href="#iterator-1">17</a></strong><br>
<strong>itertools module, <a href="#itertools">3</a>, <a href="#combinatorics">8</a></strong> </p>
<h3 id="j">J</h3>
<p><strong>json, <a href="#json">25</a>, <a href="#restrequest">36</a>, <a href="#fileformats">46</a></strong> </p>
<p><strong>json, <a href="#json">25</a>, <a href="#servingjson">36</a>, <a href="#fileformats">46</a></strong> </p>
<h3 id="l">L</h3>
<p><strong>lambda, <a href="#lambda">11</a></strong><br>
<strong>lists, <a href="#list">1</a>-<a href="#list">2</a>, <a href="#abstractbaseclasses">4</a>, <a href="#otheruses">10</a>-<a href="#comprehensions">11</a>, <a href="#sequence">18</a>-<a href="#abcsequence">19</a>, <a href="#collectionsandtheirexceptions">21</a></strong><br>
@ -135,7 +135,7 @@
<strong>sys module, <a href="#cache">13</a>, <a href="#exit">21</a>-<a href="#commandlinearguments">22</a></strong> </p>
<h3 id="t">T</h3>
<p><strong>table, <a href="#csv">26</a>, <a href="#example-1">27</a>, <a href="#table">34</a>, <a href="#numpy">37</a>-<a href="#indexing">38</a>, <a href="#dataframe">45</a>-<a href="#dataframeaggregatetransformmap">46</a></strong><br>
<strong>template, <a href="#format">6</a>, <a href="#dynamicrequest">36</a></strong><br>
<strong>template, <a href="#format">6</a>, <a href="#servinghtml">36</a></strong><br>
<strong>threading module, <a href="#threading">32</a>, <a href="#startstheappinitsownthreadandqueriesitsrestapi">36</a></strong><br>
<strong>time module, <a href="#progressbar">34</a>, <a href="#profiling">36</a></strong><br>
<strong>tuples, <a href="#tuple">3</a>, <a href="#abstractbaseclasses">4</a>, <a href="#otheruses">10</a>-<a href="#comprehensions">11</a>, <a href="#sequence">18</a>-<a href="#abcsequence">19</a></strong><br>

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