{<el>:.<10} # '<el>......'

{<el>:0} # '<el>'

* **Options can be generated dynamically: `f'{<el>:{<str/int>}[…]}'`.**

* **Adding `'='` to the expression prepends it to the output: `f'{1+1=}'` returns `'1+1=2'`.**

* **Adding `'!r'` to the expression converts object to string by calling its [repr()](#class) method.**

p.add_argument('<name>', type=<type>, nargs=1) # Mandatory first argument.

p.add_argument('<name>', type=<type>, nargs='+') # Mandatory remaining args.

p.add_argument('<name>', type=<type>, nargs='?/*') # Optional argument/s.

* **Use `'help=<str>'` to set argument description that will be displayed in help message.**

<file>.seek(0) # Moves to the start of the file.

<file>.seek(offset) # Moves 'offset' chars/bytes from the start.

<file>.seek(0, 2) # Moves to the end of the file.

return flask.render_template_string('<h1>{{title}}</h1>', title=sport)

* **Use `'render_template(filename, <kwargs>)'` to render file located in templates dir.**

* **`'request.args[<str>]'` returns parameter from the query string (URL part after '?').**

* **`'session[<str>] = <obj>'` stores session data. Needs `'app.secret_key = <str>'`.**

<Image> = Image.new('<mode>', (width, height)) # Creates new image. Also `color=<int/tuple>`.

<Image> = Image.open(<path>) # Identifies format based on file's contents.

<Image>.save(<path>) # Selects format based on extension (PNG/JPG…).

<Image>.show() # Opens image in the default preview app.

<Image>.paste(<Image>, (x, y)) # Draws passed image at the specified location.

* **`'L'` - Lightness (greyscale image). Each pixel is an int between 0 and 255.**

* **`'RGB'` - Red, green, blue (true color image). Each pixel is a tuple of three ints.**

* **`'HSV'` - Hue, saturation, value. Three ints representing color in HSV color space.**

<header>

<a href="https://gto76.github.io" rel="author">Jure Šorn</a>

</header>

<li><strong>Options can be generated dynamically: <code class="python hljs"><span class="hljs-string">f'<span class="hljs-subst">{&lt;el&gt;:{&lt;str/int&gt;}</span>[…]}'</span></code>.</strong></li>

<li><strong>Adding <code class="python hljs"><span class="hljs-string">'='</span></code> to the expression prepends it to the output: <code class="python hljs"><span class="hljs-string">f'<span class="hljs-subst">{<span class="hljs-number">1</span>+<span class="hljs-number">1</span>=}</span>'</span></code> returns <code class="python hljs"><span class="hljs-string">'1+1=2'</span></code>.</strong></li>

<li><strong>Adding <code class="python hljs"><span class="hljs-string">'!r'</span></code> to the expression converts object to string by calling its <a href="#class">repr()</a> method.</strong></li>

p.add_argument(<span class="hljs-string">'&lt;name&gt;'</span>, type=&lt;type&gt;, nargs=<span class="hljs-number">1</span>) <span class="hljs-comment"># Mandatory first argument.</span>

p.add_argument(<span class="hljs-string">'&lt;name&gt;'</span>, type=&lt;type&gt;, nargs=<span class="hljs-string">'+'</span>) <span class="hljs-comment"># Mandatory remaining args.</span>

p.add_argument(<span class="hljs-string">'&lt;name&gt;'</span>, type=&lt;type&gt;, nargs=<span class="hljs-string">'?/*'</span>) <span class="hljs-comment"># Optional argument/s.</span>

</ul><div><h3 id="fileobject">File Object</h3><pre><code class="python language-python hljs">&lt;file&gt;.seek(<span class="hljs-number">0</span>) <span class="hljs-comment"># Moves to the start of the file.</span>

&lt;file&gt;.seek(offset) <span class="hljs-comment"># Moves 'offset' chars/bytes from the start.</span>

&lt;file&gt;.seek(<span class="hljs-number">0</span>, <span class="hljs-number">2</span>) <span class="hljs-comment"># Moves to the end of the file.</span>

<li><strong>Use <code class="python hljs"><span class="hljs-string">'render_template(filename, &lt;kwargs&gt;)'</span></code> to render file located in templates dir.</strong></li>

<li><strong><code class="python hljs"><span class="hljs-string">'request.args[&lt;str&gt;]'</span></code> returns parameter from the query string (URL part after '?').</strong></li>

<li><strong><code class="python hljs"><span class="hljs-string">'session[&lt;str&gt;] = &lt;obj&gt;'</span></code> stores session data. Needs <code class="python hljs"><span class="hljs-string">'app.secret_key = &lt;str&gt;'</span></code>.</strong></li>

<pre><code class="python language-python hljs">&lt;Image&gt; = Image.new(<span class="hljs-string">'&lt;mode&gt;'</span>, (width, height)) <span class="hljs-comment"># Creates new image. Also `color=&lt;int/tuple&gt;`.</span>

&lt;Image&gt; = Image.open(&lt;path&gt;) <span class="hljs-comment"># Identifies format based on file's contents.</span>

&lt;Image&gt;.save(&lt;path&gt;) <span class="hljs-comment"># Selects format based on extension (PNG/JPG…).</span>

&lt;Image&gt;.show() <span class="hljs-comment"># Opens image in the default preview app.</span>

&lt;Image&gt;.paste(&lt;Image&gt;, (x, y)) <span class="hljs-comment"># Draws passed image at the specified location.</span>

<pre><code class="python language-python hljs">&lt;array&gt; = np.array(&lt;Image&gt;) <span class="hljs-comment"># Creates a 2d/3d NumPy array from the image.</span>

&lt;Image&gt; = Image.fromarray(np.uint8(&lt;array&gt;)) <span class="hljs-comment"># Use `&lt;array&gt;.clip(0, 255)` to clip values.</span>

<div><h3 id="modes-1">Modes</h3><ul>

<li><strong><code class="python hljs"><span class="hljs-string">'L'</span></code> - Lightness (greyscale image). Each pixel is an int between 0 and 255.</strong></li>

<li><strong><code class="python hljs"><span class="hljs-string">'RGB'</span></code> - Red, green, blue (true color image). Each pixel is a tuple of three ints.</strong></li>

<li><strong><code class="python hljs"><span class="hljs-string">'HSV'</span></code> - Hue, saturation, value. Three ints representing color in HSV color space.</strong></li>

</ul><div><h3 id="examples">Examples</h3><div><h4 id="createsapngimageofarainbowgradient">Creates a PNG image of a rainbow gradient:</h4><pre><code class="python language-python hljs">WIDTH, HEIGHT = <span class="hljs-number">100</span>, <span class="hljs-number">100</span>

n_pixels = WIDTH * HEIGHT

<footer>

<a href="https://gto76.github.io" rel="author">Jure Šorn</a>

</footer>