{ "cells": [ { "cell_type": "markdown", "id": "bb725259", "metadata": {}, "source": [ "# Modules\n", "\n", "This section teaches how modules work in Python and how quickly you can build your own reusable modules for projects.\n", "\n", "**Learning Goals**\n", "- Explain what a Python module is\n", "- Create a custom module file\n", "- Import and use module functions in another file/notebook\n", "- Organize module code in a project-friendly way" ] }, { "cell_type": "markdown", "id": "df0eaf85", "metadata": {}, "source": [ "## What Is a Module?\n", "\n", "A **module** is a Python file (`.py`) that contains reusable code (functions, classes, variables).\n", "\n", "Why this matters for projects:\n", "- You avoid copy-pasting logic\n", "- You separate concerns (I/O, processing, utilities)\n", "- You can test and reuse functionality across files" ] }, { "cell_type": "code", "execution_count": 1, "id": "5837f65b", "metadata": { "execution": { "iopub.execute_input": "2026-03-19T03:58:55.454948Z", "iopub.status.busy": "2026-03-19T03:58:55.454857Z", "iopub.status.idle": "2026-03-19T03:58:55.457396Z", "shell.execute_reply": "2026-03-19T03:58:55.457168Z" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "9.0\n", "3.141592653589793\n" ] } ], "source": [ "# Built-in module example\n", "import math\n", "\n", "print(math.sqrt(81))\n", "print(math.pi)" ] }, { "cell_type": "markdown", "id": "d0cbd546", "metadata": {}, "source": [ "## Create and Import Your Own Module\n", "\n", "A custom module is just a `.py` file.\n", "The example below writes a module file, imports it, and reuses its functions." ] }, { "cell_type": "code", "execution_count": 2, "id": "263d9f7a", "metadata": { "execution": { "iopub.execute_input": "2026-03-19T03:58:55.458533Z", "iopub.status.busy": "2026-03-19T03:58:55.458469Z", "iopub.status.idle": "2026-03-19T03:58:55.461119Z", "shell.execute_reply": "2026-03-19T03:58:55.460943Z" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "36\n", "27\n" ] } ], "source": [ "from pathlib import Path\n", "import sys\n", "\n", "module_dir = Path('.')\n", "module_dir.mkdir(parents=True, exist_ok=True)\n", "module_path = module_dir / 'my_math_tools.py'\n", "\n", "module_path.write_text(\n", " \"def square(x):\\n\"\n", " \" return x * x\\n\\n\"\n", " \"def cube(x):\\n\"\n", " \" return x * x * x\\n\",\n", " encoding='utf-8'\n", ")\n", "\n", "if str(module_dir.resolve()) not in sys.path:\n", " sys.path.insert(0, str(module_dir.resolve()))\n", "\n", "import my_math_tools\n", "\n", "print(my_math_tools.square(6))\n", "print(my_math_tools.cube(3))" ] }, { "cell_type": "code", "execution_count": 3, "id": "bb0c441c", "metadata": { "execution": { "iopub.execute_input": "2026-03-19T03:58:55.462650Z", "iopub.status.busy": "2026-03-19T03:58:55.462571Z", "iopub.status.idle": "2026-03-19T03:58:55.464036Z", "shell.execute_reply": "2026-03-19T03:58:55.463850Z" }, "tags": [ "thebe-interactive" ] }, "outputs": [], "source": [ "### Exercise: Build a Tax Module\n", "# Create a file `pricing_tools.py` with a function:\n", "# `add_tax(price, rate=0.07)` that returns price with tax.\n", "# Then import it and calculate the taxed value of 49.99.\n", "### Your code starts here.\n", "\n", "\n", "### Your code ends here." ] }, { "cell_type": "code", "execution_count": 4, "id": "2a73c8ae", "metadata": { "execution": { "iopub.execute_input": "2026-03-19T03:58:55.465047Z", "iopub.status.busy": "2026-03-19T03:58:55.464990Z", "iopub.status.idle": "2026-03-19T03:58:55.467496Z", "shell.execute_reply": "2026-03-19T03:58:55.467201Z" }, "tags": [ "hide-input" ] }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "53.49\n" ] } ], "source": [ "### Solution\n", "from pathlib import Path\n", "import sys\n", "\n", "module_dir = Path('.')\n", "module_dir.mkdir(parents=True, exist_ok=True)\n", "module_path = module_dir / 'pricing_tools.py'\n", "module_path.write_text(\n", " \"def add_tax(price, rate=0.07):\\n\"\n", " \" return price * (1 + rate)\\n\",\n", " encoding='utf-8'\n", ")\n", "\n", "if str(module_dir.resolve()) not in sys.path:\n", " sys.path.insert(0, str(module_dir.resolve()))\n", "\n", "import pricing_tools\n", "print(round(pricing_tools.add_tax(49.99), 2))\n" ] }, { "cell_type": "markdown", "id": "dc508357", "metadata": {}, "source": [ "## Module Design for Projects\n", "\n", "Simple project pattern:\n", "- one file for entry point (`main.py`)\n", "- one or more module files for reusable logic (`utils.py`, `data_ops.py`, etc.)\n", "\n", "Keep module functions:\n", "- small\n", "- single-purpose\n", "- well-named\n", "- easy to test" ] }, { "cell_type": "code", "execution_count": 5, "id": "a907bfab", "metadata": { "execution": { "iopub.execute_input": "2026-03-19T03:58:55.468684Z", "iopub.status.busy": "2026-03-19T03:58:55.468620Z", "iopub.status.idle": "2026-03-19T03:58:55.469976Z", "shell.execute_reply": "2026-03-19T03:58:55.469780Z" } }, "outputs": [], "source": [ "# Example project-style split (conceptual)\n", "# main.py\n", "# from my_math_tools import square\n", "# print(square(10))\n", "\n", "# my_math_tools.py\n", "# def square(x):\n", "# return x * x" ] }, { "cell_type": "markdown", "id": "1f394ff4", "metadata": {}, "source": [ "## Summary\n", "\n", "If students can build one custom module, they can scale to small projects:\n", "- define reusable functions once\n", "- import where needed\n", "- keep project code organized" ] } ], "metadata": { "kernelspec": { "display_name": ".venv", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.13.7" } }, "nbformat": 4, "nbformat_minor": 5 }