Python’s Silent Production Killer: Why "Pass-by-Reference" is a Lie

<p>A list that keeps growing between function calls is one of the most common Python surprises in exams and interviews. Here is why it happens, with output I ran on Python

<h2> 💡 TL;DR </h2> <p>PHP copies arrays by default. Python and JavaScript share references by default. If you switch between these languages and don't switch your mental model

<p>Here is a bug that is easy to ship. A function takes a dict of default settings and hands each new user a copy. Someone adds a tag to one user. Every future user now has that

<h2> Introduction </h2> <p>In most programming languages you learn early on to separate <em>values</em> from<br /> <em>variables</em>: a variable is a labelled box, and you drop a