Python Standard Library: What Ships Without Installing Anything

In the previous post we learned to handle errors gracefully. Now let us talk about something that will save you enormous amounts of time: Python’s standard library.

The Python Standard Library is the collection of modules that ships with every Python installation, covering file system operations, dates and times, data serialisation, mathematics, networking, testing, and compression without requiring a single third-party install. The first instinct of many beginners — and honestly of many experienced developers — is to reach for a third-party package. Often the right answer is already in the box.

The Python community has a saying: batteries included. This post is about finding the batteries.

Python Modules and the import Statement

Before exploring specific modules, a quick note on how to use them. A module is a Python file — or a package of files — that you bring into your script with import:

import math
print(math.sqrt(144))  # 12.0

If you only need one thing from a module, from x import y keeps the namespace cleaner:

from math import sqrt, pi
print(sqrt(144))  # 12.0
print(pi)         # 3.141592653589793

You can alias a module to a shorter name with as:

import datetime as dt
today = dt.date.today()

That is all there is to it. The rest is knowing which modules exist and what they do.

pathlib — File Paths Done Right

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datetime — Dates and Times

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json — Data Exchange

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random — Controlled Randomness

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dataclasses — Structured Data Without Ceremony

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Complete Example: Combining pathlib, json, random, and dataclasses

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Python Standard Library vs Third-Party Packages: When to Reach for Each

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References

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