A Python file that contains code (functions, classes, variables) that you can import and reuse in other programs.

The collection of modules that comes built into Python (such as math, random, datetime, pathlib). You do not need pip to use them.

An import style that brings in the whole module, so you use names with a prefix, like math.sqrt or random.randint.

Python’s package manager. It installs third-party packages from the Python Package Index (PyPI) so you can import them.

Python’s package manager used to install third-party packages from the Python Package Index (PyPI).

A Python file containing code (functions, classes, variables) that can be imported and reused.

A standard library module that provides an object-oriented way to work with file system paths.

A standard library module for working with dates and times.

Using Python’s Built-in Superpowers: Modules and the Standard Library — Getting Started with Python: A Gentle, Practical Introduction

Why Python Has Built-in Superpowers

Python's Toolbox

Python includes a huge toolbox of ready-made code called the standard library. You can import these tools instead of writing everything from scratch.

What Is a Module?

A module is a Python file that contains code: functions, classes, and variables. The standard library is a big collection of modules that comes with Python.

Why Import?

An import statement is like asking Python: "Bring me this toolbox so I can use its tools." You place imports at the top of your file.

What You Will Learn

You will learn two import styles, use `math`, `random`, `datetime`, `pathlib`, see what `pip` is, and practice reading docs and adapting examples.

The Two Main Import Styles

Two Import Styles

Python has two common import styles: `import module` and `from module import name`. Both let you use tools from a module in your code.

`import module`

With `import math`, you use functions with the module name as a prefix, like `math.cos` or `math.pi`. This style is very clear and beginner-friendly.

`from module import name`

With `from math import cos, pi`, you can call `cos` and `pi` directly, without `math.`. It is shorter but can be less clear if you import many names.

Which Style to Use?

As a beginner, prefer `import module` for clarity. Use `from module import name` when you often use a few tools from a module and want shorter code.

Try It: Your First Imports

Run this code and observe the output. Then change some values and run it again.

Beginner-Friendly Module: math

Meet the math Module

The `math` module provides constants like `math.pi` and functions like `math.sqrt`. It is great for more advanced calculations than basic `+ - * /`.

Useful math Tools

Common tools: `math.pi`, `math.e`, `math.sqrt(x)`, `math.ceil(x)`, `math.floor(x)`. They help with roots and rounding up or down.

Example: Movie Night

Use `math.ceil(people / seatsperrow)` to find how many full rows of seats you need. You cannot seat people in half a row, so you round up.

Beginner-Friendly Module: random

Meet the random Module

The `random` module lets programs make random choices: roll dice, shuffle lists, and pick random items. Great for games and simulations.

Useful random Tools

`random.random()` gives a float from 0.0 to 1.0. `random.randint(a, b)` gives an integer from a to b. `random.choice(list)` picks a random item.

Example: Dice and Snacks

Use `random.randint(1, 6)` to roll dice, and `random.choice(snacks)` to pick a random snack from a list. Each run can give different results.

Working with Dates and Paths: datetime and pathlib

Meet datetime

The `datetime` module helps you work with dates and times. You can get today’s date, the current time, and do math with dates safely.

datetime Example

Use `date.today()` for today’s date and `datetime.now()` for date plus time. You can subtract dates to get differences in days.

Meet pathlib

`pathlib` helps you build and inspect file paths that work across Windows, macOS, and Linux. It is safer than writing raw strings.

pathlib Example

Use `Path.cwd()` for the current folder, then build paths like `current / "notes.txt"`. The `/` operator joins path parts.

Activity: Pick the Right Module

For each situation, decide which standard library module (`math`, `random`, `datetime`, `pathlib`) you would reach for first. Think before you peek at the hints.

You want to simulate flipping a coin 100 times.

Which module? Why?

You want to find how many days are left until the last day of this year.

Which module? Why?

You want to calculate the length of the diagonal of a rectangle given its width and height.

Which module? Why?

You want to save a game score to a file called `scores.txt` in a `data` folder next to your script. You need to build that file path.

Which module? Why?

Hints (unfold in your mind, not in code):

Random choices or numbers? Think `random`.
Real-world dates and times? Think `datetime`.
Extra math formulas (like square root)? Think `math`.
File and folder locations? Think `pathlib`.

After you decide, write a short comment in your own words: "I would use X because..." for each case.

What Is pip and When Do You Need It?

Standard Library vs Extras

The standard library comes with Python. Third-party packages are extras made by others. You need a tool named `pip` to install those extras.

What pip Does

`pip` is Python’s package manager. It downloads and installs packages from PyPI so you can `import` them in your programs.

Example pip Commands

In a terminal you might run `pip install requests` or `pip install numpy`. For this course, you just need to know what pip is, not use it deeply.

Quick Check: Imports and pip

Test your understanding of import styles and pip.

Which statement about Python modules and pip is MOST accurate for you as a beginner?

I must use pip to install the math and random modules before I can import them.
Standard library modules like math and random work without pip, but I use pip to install extra third-party packages.
I should always use from module import name and never use import module.

Show Answer

Answer: B) Standard library modules like math and random work without pip, but I use pip to install extra third-party packages.

Standard library modules such as math, random, datetime, and pathlib come bundled with Python, so you can import them without pip. pip is used to install third-party packages from outside the standard library. Both import styles are valid; as a beginner, import module is often clearer.

Mini-Project: A Tiny Daily Helper Script

Combine several modules to build a tiny script. Plan it first, then code.

Goal: A script that:

Shows today’s date.
Suggests a random activity.
Saves a short log entry to a file.

Step 1: Plan the modules

Which module gives you today’s date? (Hint: `datetime`)
Which module gives random choices? (Hint: `random`)
Which module helps with file paths? (Hint: `pathlib`)

Step 2: Sketch the code (pseudocode)

Import the modules you need.
Get today’s date.
Pick a random activity from a list, like `["read", "exercise", "draw", "code"]`.
Print a friendly message using the date and activity.
Build a path to a file called `daily_log.txt` in the current folder.
Append a line like `2026-04-04: activity` to the file.

Step 3: Turn pseudocode into real Python

Try to write the real code yourself. If you get stuck, look back at the earlier examples for `datetime`, `random`, and `pathlib` and adapt them.

Review: Key Terms

Flip these cards in your mind or with a partner. Say the answer out loud before you check it.

Module: A Python file that contains code (functions, classes, variables) that you can import and reuse in other programs.
Standard library: The collection of modules that comes built into Python (such as math, random, datetime, pathlib). You do not need pip to use them.
import module: An import style that brings in the whole module, so you use names with a prefix, like math.sqrt or random.randint.
from module import name: An import style that brings specific names from a module so you can use them directly, like from math import sqrt, pi.
pip: Python’s package manager. It installs third-party packages from the Python Package Index (PyPI) so you can import them.
pathlib: A standard library module for working with file and folder paths in a clean, cross-platform way using Path objects.

Key Terms

pip: Python’s package manager used to install third-party packages from the Python Package Index (PyPI).
module: A Python file containing code (functions, classes, variables) that can be imported and reused.
pathlib: A standard library module that provides an object-oriented way to work with file system paths.
datetime: A standard library module for working with dates and times.
import statement: A line of code that tells Python to load a module or specific names from a module.
standard library: The set of modules that comes built into Python, available without separate installation.