Python Basics for Ops
The Python essentials an operations engineer reaches for every day.
Python is the default language for automation, glue code, and tooling because it’s readable and batteries-included. The core data structures you’ll use constantly:
- list — ordered, mutable (
[1, 2, 3]) - dict — key/value map (
{"name": "alex"}) - tuple — immutable sequence; set — unique items
Add functions, f-strings for formatting, and comprehensions for concise data transforms, and you can express most ops logic cleanly. Always target Python 3.
servers = [
{"name": "web1", "cpu": 82},
{"name": "web2", "cpu": 35},
{"name": "db1", "cpu": 91},
]
# Comprehension: names of servers over 80% CPU
hot = [s["name"] for s in servers if s["cpu"] > 80]
print(f"High CPU: {', '.join(hot)}") # High CPU: web1, db1
def average(values):
return sum(values) / len(values) if values else 0
print(f"Avg CPU: {average([s['cpu'] for s in servers]):.1f}")- Build a list of dicts and filter it with a comprehension.
- Write a function that returns the max value in a list, handling the empty case.
- Use an f-string to format a number to two decimal places.
- Create a virtual environment and confirm
which pythonpoints inside it.
Cheat Sheet▾
| Item | Syntax |
|---|---|
| List / dict | [1,2] / {"k": v} |
| f-string | f"{x:.2f}" |
| Comprehension | [x for x in xs if cond] |
| Function | def f(a, b=1): ... |
| Loop | for x in xs: |
| Venv | python -m venv .venv |
| Install dep | pip install pkg |
Common Interview Questions▾
When would you choose Python over a shell script?
When logic grows beyond simple command glue — needing data structures, robust error handling, API calls, or testability. Shell is best for short pipelines of CLI tools.
What is a list comprehension?
A concise way to build a list by transforming/filtering an iterable, e.g.
[x*2 for x in nums if x > 0].
Why use a virtual environment?
It isolates a project’s dependencies and Python version from the system and other projects, avoiding version conflicts.