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Itertools, Numbers, Combinatorics, OS Commands

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Jure Šorn 2 years ago
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  1. 138
      README.md
  2. 142
      index.html
  3. 8
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138
README.md
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@ -200,23 +200,23 @@ Iterator
### Itertools
```python
from itertools import count, repeat, cycle, chain, islice
import itertools as it
```
```python
<iter> = count(start=0, step=1) # Returns updated value endlessly. Accepts floats.
<iter> = repeat(<el> [, times]) # Returns element endlessly or 'times' times.
<iter> = cycle(<collection>) # Repeats the sequence endlessly.
<iter> = it.count(start=0, step=1) # Returns updated value endlessly. Accepts floats.
<iter> = it.repeat(<el> [, times]) # Returns element endlessly or 'times' times.
<iter> = it.cycle(<collection>) # Repeats the sequence endlessly.
```
```python
<iter> = chain(<coll_1>, <coll_2> [, ...]) # Empties collections in order (figuratively).
<iter> = chain.from_iterable(<coll>) # Empties collections inside a collection in order.
<iter> = it.chain(<coll>, <coll> [, ...]) # Empties collections in order (figuratively).
<iter> = it.chain.from_iterable(<coll>) # Empties collections inside a collection in order.
```
```python
<iter> = islice(<coll>, to_exclusive) # Only returns first 'to_exclusive' elements.
<iter> = islice(<coll>, from_inclusive, …) # `to_exclusive, +step_size`. Indices can be None.
<iter> = it.islice(<coll>, to_exclusive) # Only returns first 'to_exclusive' elements.
<iter> = it.islice(<coll>, from_inc, …) # `to_exclusive, +step_size`. Indices can be None.
```
@ -486,11 +486,11 @@ Format
Numbers
-------
```python
<int> = int(<float/str/bool>) # Or: math.floor(<float>)
<float> = float(<int/str/bool>) # Or: <real>e±<int>
<complex> = complex(real=0, imag=0) # Or: <real> ± <real>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.floor(<float>)
<float> = float(<int/str/bool>) # Or: <real>e±<int>
<complex> = complex(real=0, imag=0) # Or: <real> ± <real>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'`.**
@ -499,47 +499,46 @@ Numbers
### Basic Functions
```python
<num> = pow(<num>, <num>) # Or: <num> ** <num>
<num> = abs(<num>) # <float> = abs(<complex>)
<num> = round(<num> [, ±ndigits]) # `round(126, -1) == 130`
<num> = pow(<num>, <num>) # Or: <num> ** <num>
<num> = abs(<num>) # <float> = abs(<complex>)
<num> = round(<num> [, ±ndigits]) # `round(126, -1) == 130`
```
### Math
```python
from math import e, pi, inf, nan, isinf, isnan
from math import sin, cos, tan, asin, acos, atan, degrees, radians
from math import log, log10, log2
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.
```
### Statistics
```python
from statistics import mean, median, variance, stdev, quantiles, groupby
from statistics import mean, median, variance # Also: stdev, quantiles, groupby.
```
### Random
```python
from random import random, randint, choice, shuffle, gauss, seed
<float> = random() # A float inside [0, 1).
<int> = randint(from_inc, to_inc) # An int inside [from_inc, to_inc].
<el> = choice(<sequence>) # Keeps the sequence intact.
from random import random, randint, choice # Also shuffle, gauss, triangular, seed.
<float> = random() # A float inside [0, 1).
<int> = randint(from_inc, to_inc) # An int inside [from_inc, to_inc].
<el> = choice(<sequence>) # Keeps the sequence intact.
```
### Bin, Hex
```python
<int> = ±0b<bin> # Or: ±0x<hex>
<int> = int('±<bin>', 2) # Or: int('±<hex>', 16)
<int> = int('±0b<bin>', 0) # Or: int('±0x<hex>', 0)
<str> = bin(<int>) # Returns '[-]0b<bin>'.
<int> = ±0b<bin> # Or: ±0x<hex>
<int> = int('±<bin>', 2) # Or: int('±<hex>', 16)
<int> = int('±0b<bin>', 0) # Or: int('±0x<hex>', 0)
<str> = bin(<int>) # Returns '[-]0b<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.
```
@ -549,39 +548,40 @@ Combinatorics
* **If you want to print the iterator, you need to pass it to the list() function first!**
```python
from itertools import product, combinations, combinations_with_replacement, permutations
import itertools as it
```
```python
>>> product([0, 1], repeat=3)
[(0, 0, 0), (0, 0, 1), (0, 1, 0), (0, 1, 1), ..., (1, 1, 1)]
>>> 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)]
```
```python
>>> 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
>>> 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
```
```python
>>> combinations('abc', 2) # a b c
[('a', 'b'), ('a', 'c'), # a . x x
('b', 'c')] # b . . x
>>> it.combinations('abc', 2) # a b c
[('a', 'b'), ('a', 'c'), # a . x x
('b', 'c')] # b . . x
```
```python
>>> combinations_with_replacement('abc', 2) # a b c
[('a', 'a'), ('a', 'b'), ('a', 'c'), # a x x x
('b', 'b'), ('b', 'c'), # b . x x
('c', 'c')] # c . . x
>>> it.combinations_with_replacement('abc', 2) # a b c
[('a', 'a'), ('a', 'b'), ('a', 'c'), # a x x x
('b', 'b'), ('b', 'c'), # b . x x
('c', 'c')] # c . . x
```
```python
>>> 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 .
>>> 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 .
```
@ -1701,34 +1701,34 @@ import os, shutil, subprocess
```
```python
os.chdir(<path>) # Changes the current working directory.
os.mkdir(<path>, mode=0o777) # Creates a directory. Mode is in octal.
os.makedirs(<path>, mode=0o777) # Creates all path's dirs. Also: `exist_ok=False`.
os.chdir(<path>) # Changes the current working directory.
os.mkdir(<path>, mode=0o777) # Creates a directory. Permissions are in octal.
os.makedirs(<path>, mode=0o777) # Creates all path's dirs. Also: `exist_ok=False`.
```
```python
shutil.copy(from, to) # Copies the file. 'to' can exist or be a dir.
shutil.copytree(from, to) # Copies the directory. 'to' must not exist.
shutil.copy(from, to) # Copies the file. 'to' can exist or be a dir.
shutil.copytree(from, to) # Copies the directory. 'to' must not exist.
```
```python
os.rename(from, to) # Renames/moves the file or directory.
os.replace(from, to) # Same, but overwrites 'to' if it exists.
os.rename(from, to) # Renames/moves the file or directory.
os.replace(from, to) # Same, but overwrites 'to' if it exists.
```
```python
os.remove(<path>) # Deletes the file.
os.rmdir(<path>) # Deletes the empty directory.
shutil.rmtree(<path>) # Deletes the directory.
os.remove(<path>) # Deletes the file.
os.rmdir(<path>) # Deletes the empty directory.
shutil.rmtree(<path>) # Deletes the directory.
```
* **Paths can be either strings, Paths or DirEntry objects.**
* **Functions report OS related errors by raising either OSError or one of its [subclasses](#exceptions-1).**
### Shell Commands
```python
<pipe> = os.popen('<command>') # Executes command in sh/cmd and returns its stdout pipe.
<str> = <pipe>.read(size=-1) # Reads 'size' chars or until EOF. Also readline/s().
<int> = <pipe>.close() # Closes the pipe. Returns None on success, int on error.
<pipe> = os.popen('<command>') # Executes command in sh/cmd. Returns its stdout pipe.
<str> = <pipe>.read(size=-1) # Reads 'size' chars or until EOF. Also readline/s().
<int> = <pipe>.close() # Closes the pipe. Returns None on success.
```
#### Sends '1 + 1' to the basic calculator and captures its output:
@ -1754,8 +1754,8 @@ JSON
```python
import json
<str> = json.dumps(<object>) # Converts object to JSON string.
<object> = json.loads(<str>) # Converts JSON string to object.
<str> = json.dumps(<object>) # Converts object to JSON string.
<object> = json.loads(<str>) # Converts JSON string to object.
```
### Read Object from JSON File
@ -1779,8 +1779,8 @@ Pickle
```python
import pickle
<bytes> = pickle.dumps(<object>) # Converts object to bytes object.
<object> = pickle.loads(<bytes>) # Converts bytes object to object.
<bytes> = pickle.dumps(<object>) # Converts object to bytes object.
<object> = pickle.loads(<bytes>) # Converts bytes object to object.
```
### Read Object from File

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index.html
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@ -54,7 +54,7 @@
<body>
<header>
<aside>July 30, 2022</aside>
<aside>September 4, 2022</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</header>
@ -220,18 +220,18 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
&lt;list&gt; = list(&lt;iter&gt;) <span class="hljs-comment"># Returns a list of iterator's remaining elements.</span>
</code></pre></div>
<div><h3 id="itertools">Itertools</h3><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> itertools <span class="hljs-keyword">import</span> count, repeat, cycle, chain, islice
<div><h3 id="itertools">Itertools</h3><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">&lt;iter&gt; = count(start=<span class="hljs-number">0</span>, step=<span class="hljs-number">1</span>) <span class="hljs-comment"># Returns updated value endlessly. Accepts floats.</span>
&lt;iter&gt; = repeat(&lt;el&gt; [, times]) <span class="hljs-comment"># Returns element endlessly or 'times' times.</span>
&lt;iter&gt; = cycle(&lt;collection&gt;) <span class="hljs-comment"># Repeats the sequence endlessly.</span>
<pre><code class="python language-python hljs">&lt;iter&gt; = it.count(start=<span class="hljs-number">0</span>, step=<span class="hljs-number">1</span>) <span class="hljs-comment"># Returns updated value endlessly. Accepts floats.</span>
&lt;iter&gt; = it.repeat(&lt;el&gt; [, times]) <span class="hljs-comment"># Returns element endlessly or 'times' times.</span>
&lt;iter&gt; = it.cycle(&lt;collection&gt;) <span class="hljs-comment"># Repeats the sequence endlessly.</span>
</code></pre>
<pre><code class="python language-python hljs">&lt;iter&gt; = chain(&lt;coll_1&gt;, &lt;coll_2&gt; [, ...]) <span class="hljs-comment"># Empties collections in order (figuratively).</span>
&lt;iter&gt; = chain.from_iterable(&lt;coll&gt;) <span class="hljs-comment"># Empties collections inside a collection in order.</span>
<pre><code class="python language-python hljs">&lt;iter&gt; = it.chain(&lt;coll&gt;, &lt;coll&gt; [, ...]) <span class="hljs-comment"># Empties collections in order (figuratively).</span>
&lt;iter&gt; = it.chain.from_iterable(&lt;coll&gt;) <span class="hljs-comment"># Empties collections inside a collection in order.</span>
</code></pre>
<pre><code class="python language-python hljs">&lt;iter&gt; = islice(&lt;coll&gt;, to_exclusive) <span class="hljs-comment"># Only returns first 'to_exclusive' elements.</span>
&lt;iter&gt; = islice(&lt;coll&gt;, from_inclusive, …) <span class="hljs-comment"># `to_exclusive, +step_size`. Indices can be None.</span>
<pre><code class="python language-python hljs">&lt;iter&gt; = it.islice(&lt;coll&gt;, to_exclusive) <span class="hljs-comment"># Only returns first 'to_exclusive' elements.</span>
&lt;iter&gt; = it.islice(&lt;coll&gt;, from_inc, …) <span class="hljs-comment"># `to_exclusive, +step_size`. Indices can be None.</span>
</code></pre>
<div><h2 id="generator"><a href="#generator" name="generator">#</a>Generator</h2><ul>
<li><strong>Any function that contains a yield statement returns a generator.</strong></li>
@ -444,11 +444,11 @@ 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'</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.floor(&lt;float&gt;)</span>
&lt;float&gt; = float(&lt;int/str/bool&gt;) <span class="hljs-comment"># Or: &lt;real&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;real&gt; ± &lt;real&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.floor(&lt;float&gt;)</span>
&lt;float&gt; = float(&lt;int/str/bool&gt;) <span class="hljs-comment"># Or: &lt;real&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;real&gt; ± &lt;real&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>
@ -457,67 +457,67 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
<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>
</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;num&gt; ** &lt;num&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="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;num&gt; ** &lt;num&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>
</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-keyword">from</span> math <span class="hljs-keyword">import</span> sin, cos, tan, asin, acos, atan, degrees, radians
<span class="hljs-keyword">from</span> math <span class="hljs-keyword">import</span> log, log10, log2
<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>
</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, stdev, quantiles, groupby
<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>
</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, choice, shuffle, gauss, seed
&lt;float&gt; = random() <span class="hljs-comment"># A float inside [0, 1).</span>
&lt;int&gt; = randint(from_inc, to_inc) <span class="hljs-comment"># An int inside [from_inc, to_inc].</span>
&lt;el&gt; = choice(&lt;sequence&gt;) <span class="hljs-comment"># Keeps the sequence intact.</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, choice <span class="hljs-comment"># Also shuffle, gauss, triangular, seed.</span>
&lt;float&gt; = random() <span class="hljs-comment"># A float inside [0, 1).</span>
&lt;int&gt; = randint(from_inc, to_inc) <span class="hljs-comment"># An int inside [from_inc, to_inc].</span>
&lt;el&gt; = choice(&lt;sequence&gt;) <span class="hljs-comment"># Keeps the sequence intact.</span>
</code></pre></div>
<div><h3 id="binhex">Bin, Hex</h3><pre><code class="python language-python hljs">&lt;int&gt; = ±<span class="hljs-number">0</span>b&lt;bin&gt; <span class="hljs-comment"># Or: ±0x&lt;hex&gt;</span>
&lt;int&gt; = int(<span class="hljs-string">'±&lt;bin&gt;'</span>, <span class="hljs-number">2</span>) <span class="hljs-comment"># Or: int('±&lt;hex&gt;', 16)</span>
&lt;int&gt; = int(<span class="hljs-string">'±0b&lt;bin&gt;'</span>, <span class="hljs-number">0</span>) <span class="hljs-comment"># Or: int('±0x&lt;hex&gt;', 0)</span>
&lt;str&gt; = bin(&lt;int&gt;) <span class="hljs-comment"># Returns '[-]0b&lt;bin&gt;'.</span>
<div><h3 id="binhex">Bin, Hex</h3><pre><code class="python language-python hljs">&lt;int&gt; = ±<span class="hljs-number">0</span>b&lt;bin&gt; <span class="hljs-comment"># Or: ±0x&lt;hex&gt;</span>
&lt;int&gt; = int(<span class="hljs-string">'±&lt;bin&gt;'</span>, <span class="hljs-number">2</span>) <span class="hljs-comment"># Or: int('±&lt;hex&gt;', 16)</span>
&lt;int&gt; = int(<span class="hljs-string">'±0b&lt;bin&gt;'</span>, <span class="hljs-number">0</span>) <span class="hljs-comment"># Or: int('±0x&lt;hex&gt;', 0)</span>
&lt;str&gt; = bin(&lt;int&gt;) <span class="hljs-comment"># Returns '[-]0b&lt;bin&gt;'.</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><ul>
<li><strong>Every function returns an iterator.</strong></li>
<li><strong>If you want to print the iterator, you need to pass it to the list() function first!</strong></li>
</ul><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> itertools <span class="hljs-keyword">import</span> product, combinations, combinations_with_replacement, permutations
</ul><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>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">1</span>, <span class="hljs-number">1</span>)]
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>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>)]
</code></pre>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>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>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>
</code></pre>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>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>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>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>
</code></pre>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>combinations_with_replacement(<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">'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">'b'</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">'c'</span>)] <span class="hljs-comment"># c . . x</span>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>it.combinations_with_replacement(<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">'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">'b'</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">'c'</span>)] <span class="hljs-comment"># c . . x</span>
</code></pre>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>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>
<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>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>
<div><h2 id="datetime"><a href="#datetime" name="datetime">#</a>Datetime</h2><ul>
<li><strong>Module 'datetime' provides 'date' <code class="apache hljs"><span class="hljs-section">&lt;D&gt;</span></code>, 'time' <code class="apache hljs"><span class="hljs-section">&lt;T&gt;</span></code>, 'datetime' <code class="apache hljs"><span class="hljs-section">&lt;DT&gt;</span></code> and 'timedelta' <code class="apache hljs"><span class="hljs-section">&lt;TD&gt;</span></code> classes. All are immutable and hashable.</strong></li>
@ -1434,27 +1434,27 @@ value = args.&lt;name&gt;
<div><h2 id="oscommands"><a href="#oscommands" name="oscommands">#</a>OS Commands</h2><pre><code class="python language-python hljs"><span class="hljs-keyword">import</span> os, shutil, subprocess
</code></pre></div>
<pre><code class="python language-python hljs">os.chdir(&lt;path&gt;) <span class="hljs-comment"># Changes the current working directory.</span>
os.mkdir(&lt;path&gt;, mode=<span class="hljs-number">0o777</span>) <span class="hljs-comment"># Creates a directory. Mode is in octal.</span>
os.makedirs(&lt;path&gt;, mode=<span class="hljs-number">0o777</span>) <span class="hljs-comment"># Creates all path's dirs. Also: `exist_ok=False`.</span>
<pre><code class="python language-python hljs">os.chdir(&lt;path&gt;) <span class="hljs-comment"># Changes the current working directory.</span>
os.mkdir(&lt;path&gt;, mode=<span class="hljs-number">0o777</span>) <span class="hljs-comment"># Creates a directory. Permissions are in octal.</span>
os.makedirs(&lt;path&gt;, mode=<span class="hljs-number">0o777</span>) <span class="hljs-comment"># Creates all path's dirs. Also: `exist_ok=False`.</span>
</code></pre>
<pre><code class="python language-python hljs">shutil.copy(from, to) <span class="hljs-comment"># Copies the file. 'to' can exist or be a dir.</span>
shutil.copytree(from, to) <span class="hljs-comment"># Copies the directory. 'to' must not exist.</span>
<pre><code class="python language-python hljs">shutil.copy(from, to) <span class="hljs-comment"># Copies the file. 'to' can exist or be a dir.</span>
shutil.copytree(from, to) <span class="hljs-comment"># Copies the directory. 'to' must not exist.</span>
</code></pre>
<pre><code class="python language-python hljs">os.rename(from, to) <span class="hljs-comment"># Renames/moves the file or directory.</span>
os.replace(from, to) <span class="hljs-comment"># Same, but overwrites 'to' if it exists.</span>
<pre><code class="python language-python hljs">os.rename(from, to) <span class="hljs-comment"># Renames/moves the file or directory.</span>
os.replace(from, to) <span class="hljs-comment"># Same, but overwrites 'to' if it exists.</span>
</code></pre>
<pre><code class="python language-python hljs">os.remove(&lt;path&gt;) <span class="hljs-comment"># Deletes the file.</span>
os.rmdir(&lt;path&gt;) <span class="hljs-comment"># Deletes the empty directory.</span>
shutil.rmtree(&lt;path&gt;) <span class="hljs-comment"># Deletes the directory.</span>
<pre><code class="python language-python hljs">os.remove(&lt;path&gt;) <span class="hljs-comment"># Deletes the file.</span>
os.rmdir(&lt;path&gt;) <span class="hljs-comment"># Deletes the empty directory.</span>
shutil.rmtree(&lt;path&gt;) <span class="hljs-comment"># Deletes the directory.</span>
</code></pre>
<ul>
<li><strong>Paths can be either strings, Paths or DirEntry objects.</strong></li>
<li><strong>Functions report OS related errors by raising either OSError or one of its <a href="#exceptions-1">subclasses</a>.</strong></li>
</ul>
<div><h3 id="shellcommands">Shell Commands</h3><pre><code class="python language-python hljs">&lt;pipe&gt; = os.popen(<span class="hljs-string">'&lt;command&gt;'</span>) <span class="hljs-comment"># Executes command in sh/cmd and returns its stdout pipe.</span>
&lt;str&gt; = &lt;pipe&gt;.read(size=<span class="hljs-number">-1</span>) <span class="hljs-comment"># Reads 'size' chars or until EOF. Also readline/s().</span>
&lt;int&gt; = &lt;pipe&gt;.close() <span class="hljs-comment"># Closes the pipe. Returns None on success, int on error.</span>
<div><h3 id="shellcommands">Shell Commands</h3><pre><code class="python language-python hljs">&lt;pipe&gt; = os.popen(<span class="hljs-string">'&lt;command&gt;'</span>) <span class="hljs-comment"># Executes command in sh/cmd. Returns its stdout pipe.</span>
&lt;str&gt; = &lt;pipe&gt;.read(size=<span class="hljs-number">-1</span>) <span class="hljs-comment"># Reads 'size' chars or until EOF. Also readline/s().</span>
&lt;int&gt; = &lt;pipe&gt;.close() <span class="hljs-comment"># Closes the pipe. Returns None on success.</span>
</code></pre></div>
<div><h4 id="sends11tothebasiccalculatorandcapturesitsoutput">Sends '1 + 1' to the basic calculator and captures its output:</h4><pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>subprocess.run(<span class="hljs-string">'bc'</span>, input=<span class="hljs-string">'1 + 1\n'</span>, capture_output=<span class="hljs-keyword">True</span>, text=<span class="hljs-keyword">True</span>)
@ -1470,8 +1470,8 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
</code></pre></div>
<div><h2 id="json"><a href="#json" name="json">#</a>JSON</h2><p><strong>Text file format for storing collections of strings and numbers.</strong></p><pre><code class="python language-python hljs"><span class="hljs-keyword">import</span> json
&lt;str&gt; = json.dumps(&lt;object&gt;) <span class="hljs-comment"># Converts object to JSON string.</span>
&lt;object&gt; = json.loads(&lt;str&gt;) <span class="hljs-comment"># Converts JSON string to object.</span>
&lt;str&gt; = json.dumps(&lt;object&gt;) <span class="hljs-comment"># Converts object to JSON string.</span>
&lt;object&gt; = json.loads(&lt;str&gt;) <span class="hljs-comment"># Converts JSON string to object.</span>
</code></pre></div>
@ -1486,8 +1486,8 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
</code></pre></div>
<div><h2 id="pickle"><a href="#pickle" name="pickle">#</a>Pickle</h2><p><strong>Binary file format for storing Python objects.</strong></p><pre><code class="python language-python hljs"><span class="hljs-keyword">import</span> pickle
&lt;bytes&gt; = pickle.dumps(&lt;object&gt;) <span class="hljs-comment"># Converts object to bytes object.</span>
&lt;object&gt; = pickle.loads(&lt;bytes&gt;) <span class="hljs-comment"># Converts bytes object to object.</span>
&lt;bytes&gt; = pickle.dumps(&lt;object&gt;) <span class="hljs-comment"># Converts object to bytes object.</span>
&lt;object&gt; = pickle.loads(&lt;bytes&gt;) <span class="hljs-comment"># Converts bytes object to object.</span>
</code></pre></div>
@ -2906,7 +2906,7 @@ $ pyinstaller script.py --add-data '&lt;path&gt;:.' <span class="hljs-comment">
<footer>
<aside>July 30, 2022</aside>
<aside>September 4, 2022</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</footer>

8
parse.js
View File

@ -86,12 +86,12 @@ const DATACLASS =
'&lt;tuple&gt; = (<span class="hljs-string">\'&lt;attr_name&gt;\'</span>, &lt;type&gt; [, &lt;default_value&gt;])';
const SHUTIL_COPY =
'shutil.copy(from, to) <span class="hljs-comment"># Copies the file. \'to\' can exist or be a dir.</span>\n' +
'shutil.copytree(from, to) <span class="hljs-comment"># Copies the directory. \'to\' must not exist.</span>\n';
'shutil.copy(from, to) <span class="hljs-comment"># Copies the file. \'to\' can exist or be a dir.</span>\n' +
'shutil.copytree(from, to) <span class="hljs-comment"># Copies the directory. \'to\' must not exist.</span>\n';
const OS_RENAME =
'os.rename(from, to) <span class="hljs-comment"># Renames/moves the file or directory.</span>\n' +
'os.replace(from, to) <span class="hljs-comment"># Same, but overwrites \'to\' if it exists.</span>\n';
'os.rename(from, to) <span class="hljs-comment"># Renames/moves the file or directory.</span>\n' +
'os.replace(from, to) <span class="hljs-comment"># Same, but overwrites \'to\' if it exists.</span>\n';
const STRUCT_FORMAT =
'<span class="hljs-section">\'&lt;n&gt;s\'</span><span class="hljs-attribute"></span>';

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