added 18th Python tip

Author: learnbyexample

README.md

@@ -56,6 +56,7 @@ I'm addicted to reading fantasy/sci-fi books, so I have a [blog](https://learnby
 
 ## Tips
 
+* [Python tip 18: arbitrary number of arguments](https://learnbyexample.github.io/tips/python-tip-18/)
 * [Vim tip 16: terminal mode](https://learnbyexample.github.io/tips/vim-tip-16/)
 * [CLI tip 17: common and unique lines](https://learnbyexample.github.io/tips/cli-tip-17/)
 * [Python tip 17: counting frequency of items](https://learnbyexample.github.io/tips/python-tip-17/)

atom.xml

@@ -5,8 +5,61 @@
 	<link href="https://learnbyexample.github.io/atom.xml" rel="self" type="application/atom+xml"/>
   <link href="https://learnbyexample.github.io"/>
 	<generator uri="https://www.getzola.org/">Zola</generator>
-	<updated>2022-10-18T00:00:00+00:00</updated>
+	<updated>2022-10-26T00:00:00+00:00</updated>
 	<id>https://learnbyexample.github.io/atom.xml</id>
+	<entry xml:lang="en">
+		<title>Python tip 18: arbitrary number of arguments</title>
+		<published>2022-10-26T00:00:00+00:00</published>
+		<updated>2022-10-26T00:00:00+00:00</updated>
+		<link rel="alternate" href="https://learnbyexample.github.io/tips/python-tip-18/" type="text/html"/>
+		<id>https://learnbyexample.github.io/tips/python-tip-18/</id>
+		<content type="html">&lt;p&gt;The &lt;code&gt;print()&lt;&#x2F;code&gt; function can accept zero or more values separated by a comma. Here&#x27;s how the function arguments are shown in &lt;code&gt;help(print)&lt;&#x2F;code&gt;:&lt;&#x2F;p&gt;
+&lt;pre data-lang=&quot;python&quot; style=&quot;background-color:#f5f5f5;color:#1f1f1f;&quot; class=&quot;language-python &quot;&gt;&lt;code class=&quot;language-python&quot; data-lang=&quot;python&quot;&gt;&lt;span style=&quot;color:#b39f04;&quot;&gt;print&lt;&#x2F;span&gt;&lt;span&gt;(value, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;...&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;sep&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;=&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39; &amp;#39;&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;end&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;=&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;&lt;&#x2F;span&gt;&lt;span style=&quot;color:#aeb52b;&quot;&gt;\n&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;file&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;=&lt;&#x2F;span&gt;&lt;span&gt;sys.stdout, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;flush&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;=&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;False&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;&#x2F;code&gt;&lt;&#x2F;pre&gt;
+&lt;p&gt;Here are some examples with varying number of arguments passed to the &lt;code&gt;print()&lt;&#x2F;code&gt; function:&lt;&#x2F;p&gt;
+&lt;pre data-lang=&quot;python&quot; style=&quot;background-color:#f5f5f5;color:#1f1f1f;&quot; class=&quot;language-python &quot;&gt;&lt;code class=&quot;language-python&quot; data-lang=&quot;python&quot;&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b39f04;&quot;&gt;print&lt;&#x2F;span&gt;&lt;span&gt;()
+&lt;&#x2F;span&gt;&lt;span&gt;
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b39f04;&quot;&gt;print&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;hello&amp;#39;&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;span&gt;hello
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b39f04;&quot;&gt;print&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;42&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;22&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&#x2F;&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;7&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;-&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;100&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;42 3.142857142857143 &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;-&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;100
+&lt;&#x2F;span&gt;&lt;&#x2F;code&gt;&lt;&#x2F;pre&gt;
+&lt;p&gt;You can write your own functions to accept arbitrary number of arguments as well. The packing syntax is similar to &lt;a href=&quot;https:&#x2F;&#x2F;learnbyexample.github.io&#x2F;tips&#x2F;python-tip-14&#x2F;&quot;&gt;sequence unpacking&lt;&#x2F;a&gt;. A &lt;code&gt;*&lt;&#x2F;code&gt; prefix to an argument name will allow it to accept zero or more values. Such an argument will be packed as a &lt;code&gt;tuple&lt;&#x2F;code&gt; data type and it should always be specified after positional arguments (if any). &lt;code&gt;args&lt;&#x2F;code&gt; is often used as the variable name for this purpose. Here&#x27;s an example:&lt;&#x2F;p&gt;
+&lt;pre data-lang=&quot;python&quot; style=&quot;background-color:#f5f5f5;color:#1f1f1f;&quot; class=&quot;language-python &quot;&gt;&lt;code class=&quot;language-python&quot; data-lang=&quot;python&quot;&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;background-color:#562d56bf;color:#f8f8f8;&quot;&gt;def&lt;&#x2F;span&gt;&lt;span&gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;many&lt;&#x2F;span&gt;&lt;span&gt;(x, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;*&lt;&#x2F;span&gt;&lt;span&gt;args):
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;...     &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b39f04;&quot;&gt;print&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#668f14;&quot;&gt;f&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;&lt;&#x2F;span&gt;&lt;span&gt;{x = }&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;; &lt;&#x2F;span&gt;&lt;span&gt;{args = }&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;... 
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;many&lt;&#x2F;span&gt;&lt;span&gt;()
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;Traceback &lt;&#x2F;span&gt;&lt;span&gt;(most recent call last):
+&lt;&#x2F;span&gt;&lt;span&gt;  File &lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;quot;&amp;lt;stdin&amp;gt;&amp;quot;&lt;&#x2F;span&gt;&lt;span&gt;, line &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;in &amp;lt;&lt;&#x2F;span&gt;&lt;span&gt;module&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#a2a001;&quot;&gt;TypeError&lt;&#x2F;span&gt;&lt;span&gt;: &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;many&lt;&#x2F;span&gt;&lt;span&gt;() missing &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1 &lt;&#x2F;span&gt;&lt;span&gt;required positional argument: &lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;x&amp;#39;
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;many&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;span&gt;x &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;= &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1&lt;&#x2F;span&gt;&lt;span&gt;; args &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;= &lt;&#x2F;span&gt;&lt;span&gt;()
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;many&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;two&amp;#39;&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;3&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;span&gt;x &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;= &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1&lt;&#x2F;span&gt;&lt;span&gt;; args &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;= &lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#d07711;&quot;&gt;&amp;#39;two&amp;#39;&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;3&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;&#x2F;code&gt;&lt;&#x2F;pre&gt;
+&lt;p&gt;Here&#x27;s a more practical example:&lt;&#x2F;p&gt;
+&lt;pre data-lang=&quot;python&quot; style=&quot;background-color:#f5f5f5;color:#1f1f1f;&quot; class=&quot;language-python &quot;&gt;&lt;code class=&quot;language-python&quot; data-lang=&quot;python&quot;&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;background-color:#562d56bf;color:#f8f8f8;&quot;&gt;def&lt;&#x2F;span&gt;&lt;span&gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;sum_nums&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;*&lt;&#x2F;span&gt;&lt;span&gt;args):
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;...     &lt;&#x2F;span&gt;&lt;span&gt;total &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;= &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;0
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;...     &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;for &lt;&#x2F;span&gt;&lt;span&gt;n &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;in &lt;&#x2F;span&gt;&lt;span&gt;args:
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;...         &lt;&#x2F;span&gt;&lt;span&gt;total &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;+= &lt;&#x2F;span&gt;&lt;span&gt;n
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;...     &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;return &lt;&#x2F;span&gt;&lt;span&gt;total
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;... 
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;sum_nums&lt;&#x2F;span&gt;&lt;span&gt;()
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;0
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;sum_nums&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;3&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;-&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;8&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;-&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;5
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;sum_nums&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;2&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;3&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;4&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;5&lt;&#x2F;span&gt;&lt;span&gt;)
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;15
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;&amp;gt;&amp;gt;&amp;gt; &lt;&#x2F;span&gt;&lt;span style=&quot;color:#5597d6;&quot;&gt;sum_nums&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#72ab00;&quot;&gt;*&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b39f04;&quot;&gt;range&lt;&#x2F;span&gt;&lt;span&gt;(&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;1&lt;&#x2F;span&gt;&lt;span&gt;, &lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;6&lt;&#x2F;span&gt;&lt;span&gt;))
+&lt;&#x2F;span&gt;&lt;span style=&quot;color:#b3933a;&quot;&gt;15
+&lt;&#x2F;span&gt;&lt;&#x2F;code&gt;&lt;&#x2F;pre&gt;
+&lt;p&gt;&lt;img src=&quot;&#x2F;images&#x2F;info.svg&quot; alt=&quot;info&quot; &#x2F;&gt; Use &lt;code&gt;**&lt;&#x2F;code&gt; prefix to accept arbitrary number of keyword arguments. See also &lt;a href=&quot;https:&#x2F;&#x2F;docs.python.org&#x2F;3&#x2F;tutorial&#x2F;controlflow.html#arbitrary-argument-lists&quot;&gt;docs.python: Arbitrary Argument Lists&lt;&#x2F;a&gt;.&lt;&#x2F;p&gt;
+&lt;p&gt;&lt;strong&gt;Video demo&lt;&#x2F;strong&gt;:&lt;&#x2F;p&gt;
+&lt;p align=&quot;center&quot;&gt;&lt;iframe width=&quot;560&quot; height=&quot;315&quot; loading=&quot;lazy&quot; src=&quot;https:&#x2F;&#x2F;www.youtube.com&#x2F;embed&#x2F;kp0TQgguiBI&quot; title=&quot;YouTube video player&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; clipboard-write; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen&gt;&lt;&#x2F;iframe&gt;&lt;&#x2F;p&gt;
+&lt;br&gt;
+&lt;p&gt;&lt;img src=&quot;&#x2F;images&#x2F;info.svg&quot; alt=&quot;info&quot; &#x2F;&gt; See also my &lt;a href=&quot;https:&#x2F;&#x2F;github.com&#x2F;learnbyexample&#x2F;100_page_python_intro&quot;&gt;100 Page Python Intro&lt;&#x2F;a&gt; ebook.&lt;&#x2F;p&gt;
+</content>
+	</entry>
 	<entry xml:lang="en">
 		<title>Vim tip 16: terminal mode</title>
 		<published>2022-10-18T00:00:00+00:00</published>

sitemap.xml

@@ -372,7 +372,7 @@
     </url>
     <url>
         <loc>https://learnbyexample.github.io/tips/</loc>
-        <lastmod>2022-10-06</lastmod>
+        <lastmod>2022-10-26</lastmod>
     </url>
     <url>
         <loc>https://learnbyexample.github.io/tips/cli-tip-1/</loc>
@@ -478,6 +478,10 @@
         <loc>https://learnbyexample.github.io/tips/python-tip-17/</loc>
         <lastmod>2022-10-06</lastmod>
     </url>
+    <url>
+        <loc>https://learnbyexample.github.io/tips/python-tip-18/</loc>
+        <lastmod>2022-10-26</lastmod>
+    </url>
     <url>
         <loc>https://learnbyexample.github.io/tips/python-tip-2/</loc>
         <lastmod>2022-05-16</lastmod>