Skip to content

Commit

Permalink
Regex
Browse files Browse the repository at this point in the history
  • Loading branch information
@gto76
gto76 committed Mar 12, 2024
1 parent ce214f8 commit 794a359
Show file tree
Hide file tree
Showing 2 changed files with 34 additions and 36 deletions.
33 changes: 16 additions & 17 deletions README.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -351,36 +351,35 @@ Regex

```python
import re
<str> = re.sub(<regex>, new, text, count=0) # Substitutes all occurrences with 'new'.
<list> = re.findall(<regex>, text) # Returns all occurrences as strings.
<list> = re.split(<regex>, text, maxsplit=0) # Add brackets around regex to include matches.
<Match> = re.search(<regex>, text) # First occurrence of the pattern or None.
<Match> = re.match(<regex>, text) # Searches only at the beginning of the text.
<iter> = re.finditer(<regex>, text) # Returns all occurrences as Match objects.
<str> = re.sub(r'<regex>', new, text, count=0) # Substitutes all occurrences with 'new'.
<list> = re.findall(r'<regex>', text) # Returns all occurrences as strings.
<list> = re.split(r'<regex>', text, maxsplit=0) # Add brackets around regex to keep matches.
<Match> = re.search(r'<regex>', text) # First occurrence of the pattern or None.
<Match> = re.match(r'<regex>', text) # Searches only at the beginning of the text.
<iter> = re.finditer(r'<regex>', text) # Returns all occurrences as Match objects.
```

* **Argument 'new' can be a function that accepts a Match object and returns a string.**
* **Raw string literals do not interpret escape sequences, thus enabling us to use regex-specific escape sequences that cause SyntaxWarning in normal string literals.**
* **Argument 'new' of re.sub() can be a function that accepts a Match object and returns a str.**
* **Argument `'flags=re.IGNORECASE'` can be used with all functions.**
* **Argument `'flags=re.MULTILINE'` makes `'^'` and `'$'` match the start/end of each line.**
* **Argument `'flags=re.DOTALL'` makes `'.'` also accept the `'\n'`.**
* **Use `r'\1'` or `'\\1'` for backreference (`'\1'` returns a character with octal code 1).**
* **Add `'?'` after `'*'` and `'+'` to make them non-greedy.**
* **`'re.compile(<regex>)'` returns a Pattern object with methods sub(), findall(), …**

### Match Object
```python
<str> = <Match>.group() # Returns the whole match. Also group(0).
<str> = <Match>.group(1) # Returns part inside the first brackets.
<tuple> = <Match>.groups() # Returns all bracketed parts.
<int> = <Match>.start() # Returns start index of the match.
<int> = <Match>.end() # Returns exclusive end index of the match.
<str> = <Match>.group() # Returns the whole match. Also group(0).
<str> = <Match>.group(1) # Returns part inside the first brackets.
<tuple> = <Match>.groups() # Returns all bracketed parts.
<int> = <Match>.start() # Returns start index of the match.
<int> = <Match>.end() # Returns exclusive end index of the match.
```

### Special Sequences
```python
'\d' == '[0-9]' # Also [०-९…]. Matches a decimal character.
'\w' == '[a-zA-Z0-9_]' # Also [ª²³…]. Matches an alphanumeric or _.
'\s' == '[ \t\n\r\f\v]' # Also [\x1c-\x1f…]. Matches a whitespace.
'\d' == '[0-9]' # Also [०-९…]. Matches a decimal character.
'\w' == '[a-zA-Z0-9_]' # Also [ª²³…]. Matches an alphanumeric or _.
'\s' == '[ \t\n\r\f\v]' # Also [\x1c-\x1f…]. Matches a whitespace.
```

* **By default, decimal characters, alphanumerics and whitespaces from all alphabets are matched unless `'flags=re.ASCII'` argument is used.**
Expand Down
37 changes: 18 additions & 19 deletions index.html
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@

<body>
<header>
<aside>March 11, 2024</aside>
<aside>March 12, 2024</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</header>

Expand Down Expand Up @@ -325,34 +325,33 @@
</code></pre></div>

<div><h2 id="regex"><a href="#regex" name="regex">#</a>Regex</h2><p><strong>Functions for regular expression matching.</strong></p><pre><code class="python language-python hljs"><span class="hljs-keyword">import</span> re
&lt;str&gt; = re.sub(&lt;regex&gt;, new, text, count=<span class="hljs-number">0</span>) <span class="hljs-comment"># Substitutes all occurrences with 'new'.</span>
&lt;list&gt; = re.findall(&lt;regex&gt;, text) <span class="hljs-comment"># Returns all occurrences as strings.</span>
&lt;list&gt; = re.split(&lt;regex&gt;, text, maxsplit=<span class="hljs-number">0</span>) <span class="hljs-comment"># Add brackets around regex to include matches.</span>
&lt;Match&gt; = re.search(&lt;regex&gt;, text) <span class="hljs-comment"># First occurrence of the pattern or None.</span>
&lt;Match&gt; = re.match(&lt;regex&gt;, text) <span class="hljs-comment"># Searches only at the beginning of the text.</span>
&lt;iter&gt; = re.finditer(&lt;regex&gt;, text) <span class="hljs-comment"># Returns all occurrences as Match objects.</span>
&lt;str&gt; = re.sub(<span class="hljs-string">r'&lt;regex&gt;'</span>, new, text, count=<span class="hljs-number">0</span>) <span class="hljs-comment"># Substitutes all occurrences with 'new'.</span>
&lt;list&gt; = re.findall(<span class="hljs-string">r'&lt;regex&gt;'</span>, text) <span class="hljs-comment"># Returns all occurrences as strings.</span>
&lt;list&gt; = re.split(<span class="hljs-string">r'&lt;regex&gt;'</span>, text, maxsplit=<span class="hljs-number">0</span>) <span class="hljs-comment"># Add brackets around regex to keep matches.</span>
&lt;Match&gt; = re.search(<span class="hljs-string">r'&lt;regex&gt;'</span>, text) <span class="hljs-comment"># First occurrence of the pattern or None.</span>
&lt;Match&gt; = re.match(<span class="hljs-string">r'&lt;regex&gt;'</span>, text) <span class="hljs-comment"># Searches only at the beginning of the text.</span>
&lt;iter&gt; = re.finditer(<span class="hljs-string">r'&lt;regex&gt;'</span>, text) <span class="hljs-comment"># Returns all occurrences as Match objects.</span>
</code></pre></div>


<ul>
<li><strong>Argument 'new' can be a function that accepts a Match object and returns a string.</strong></li>
<li><strong>Raw string literals do not interpret escape sequences, thus enabling us to use regex-specific escape sequences that cause SyntaxWarning in normal string literals.</strong></li>
<li><strong>Argument 'new' of re.sub() can be a function that accepts a Match object and returns a str.</strong></li>
<li><strong>Argument <code class="python hljs"><span class="hljs-string">'flags=re.IGNORECASE'</span></code> can be used with all functions.</strong></li>
<li><strong>Argument <code class="python hljs"><span class="hljs-string">'flags=re.MULTILINE'</span></code> makes <code class="python hljs"><span class="hljs-string">'^'</span></code> and <code class="python hljs"><span class="hljs-string">'$'</span></code> match the start/end of each line.</strong></li>
<li><strong>Argument <code class="python hljs"><span class="hljs-string">'flags=re.DOTALL'</span></code> makes <code class="python hljs"><span class="hljs-string">'.'</span></code> also accept the <code class="python hljs"><span class="hljs-string">'\n'</span></code>.</strong></li>
<li><strong>Use <code class="python hljs"><span class="hljs-string">r'\1'</span></code> or <code class="python hljs"><span class="hljs-string">'\\1'</span></code> for backreference (<code class="python hljs"><span class="hljs-string">'\1'</span></code> returns a character with octal code 1).</strong></li>
<li><strong>Add <code class="python hljs"><span class="hljs-string">'?'</span></code> after <code class="python hljs"><span class="hljs-string">'*'</span></code> and <code class="python hljs"><span class="hljs-string">'+'</span></code> to make them non-greedy.</strong></li>
<li><strong><code class="python hljs"><span class="hljs-string">'re.compile(&lt;regex&gt;)'</span></code> returns a Pattern object with methods sub(), findall(), …</strong></li>
</ul>
<div><h3 id="matchobject">Match Object</h3><pre><code class="python language-python hljs">&lt;str&gt; = &lt;Match&gt;.group() <span class="hljs-comment"># Returns the whole match. Also group(0).</span>
&lt;str&gt; = &lt;Match&gt;.group(<span class="hljs-number">1</span>) <span class="hljs-comment"># Returns part inside the first brackets.</span>
&lt;tuple&gt; = &lt;Match&gt;.groups() <span class="hljs-comment"># Returns all bracketed parts.</span>
&lt;int&gt; = &lt;Match&gt;.start() <span class="hljs-comment"># Returns start index of the match.</span>
&lt;int&gt; = &lt;Match&gt;.end() <span class="hljs-comment"># Returns exclusive end index of the match.</span>
<div><h3 id="matchobject">Match Object</h3><pre><code class="python language-python hljs">&lt;str&gt; = &lt;Match&gt;.group() <span class="hljs-comment"># Returns the whole match. Also group(0).</span>
&lt;str&gt; = &lt;Match&gt;.group(<span class="hljs-number">1</span>) <span class="hljs-comment"># Returns part inside the first brackets.</span>
&lt;tuple&gt; = &lt;Match&gt;.groups() <span class="hljs-comment"># Returns all bracketed parts.</span>
&lt;int&gt; = &lt;Match&gt;.start() <span class="hljs-comment"># Returns start index of the match.</span>
&lt;int&gt; = &lt;Match&gt;.end() <span class="hljs-comment"># Returns exclusive end index of the match.</span>
</code></pre></div>

<div><h3 id="specialsequences">Special Sequences</h3><pre><code class="python language-python hljs"><span class="hljs-string">'\d'</span> == <span class="hljs-string">'[0-9]'</span> <span class="hljs-comment"># Also [०-९…]. Matches a decimal character.</span>
<span class="hljs-string">'\w'</span> == <span class="hljs-string">'[a-zA-Z0-9_]'</span> <span class="hljs-comment"># Also [ª²³…]. Matches an alphanumeric or _.</span>
<span class="hljs-string">'\s'</span> == <span class="hljs-string">'[ \t\n\r\f\v]'</span> <span class="hljs-comment"># Also [\x1c-\x1f…]. Matches a whitespace.</span>
<div><h3 id="specialsequences">Special Sequences</h3><pre><code class="python language-python hljs"><span class="hljs-string">'\d'</span> == <span class="hljs-string">'[0-9]'</span> <span class="hljs-comment"># Also [०-९…]. Matches a decimal character.</span>
<span class="hljs-string">'\w'</span> == <span class="hljs-string">'[a-zA-Z0-9_]'</span> <span class="hljs-comment"># Also [ª²³…]. Matches an alphanumeric or _.</span>
<span class="hljs-string">'\s'</span> == <span class="hljs-string">'[ \t\n\r\f\v]'</span> <span class="hljs-comment"># Also [\x1c-\x1f…]. Matches a whitespace.</span>
</code></pre></div>

<ul>
Expand Down Expand Up @@ -2934,7 +2933,7 @@ <h3 id="format-2">Format</h3><div><h4 id="forstandardtypesizesandmanualalignment


<footer>
<aside>March 11, 2024</aside>
<aside>March 12, 2024</aside>
<a href="https://gto76.github.io" rel="author">Jure Šorn</a>
</footer>

Expand Down

0 comments on commit 794a359

Please sign in to comment.