When you add a function to a Python file, its purpose may not be clear to someone who calls it later. A Python docstring is a string at the start of a definition that Python makes available as documentation. This…
When a Python script needs to handle each value in a collection, repeating the same code by hand gets in the way. A loop repeats an indented block, with for taking values one at a time and while repeating as…
`”banana”.find(“pear”)` returns `-1` when the text is absent. I’m fascinated that a failed search has a clear result, while `-1` can still act as a valid slice position. You can separate the idea of a text fragment from the operation…
With `axis=0` on a 2×3 array, the result has one row index for each column. I like how that lets each column identify its own winning position. Those indices can guide a separate lookup for each column’s winner. `np.argmax` returns…
The `+` in `8 + 3` adds, while the same symbol in `”py” + “thon”` joins text. I like that one familiar symbol can do both jobs, depending on what it acts on. Once you can name the operation, choosing…
You have probably typed git checkout feature-branch a hundred times without thinking about it. Then one day you tried to restore a deleted file and found git checkout handles that too. Single command doing two completely different jobs. That confusion…
A city of ten million people generates more sensor data before lunch than most enterprises touch in a year. Traffic cameras, smart meters, streetlight controllers — millions of them per metro area, all streaming constantly. Municipal servers bought a decade…
Python never shipped a switch statement, so generations of us built our own out of long if-elif chains and dict lookups. I ran every style on Python 3.11.16 this morning, side by side, and the surprise was not speed. You…
10 / 0 without a handler prints a traceback ending in ZeroDivisionError. I ran that on Python 3.11.16, then wrapped the line in try except and the script kept running instead of stopping. I kept wrapping whole files in try…
Python lists hold an ordered row of references you can read, change, and grow in place. I hit the classic alias surprise while verifying the samples for this page, I ran b = a followed by b.append(99) on Python 3.11.16…