Understanding Python Terminology: Module, Package, Library, and Framework

When starting to learn a programming language, one of the first challenges is getting familiar with the terminology. In Python, terms like module, package, library, and framework are commonly used, but their distinctions aren’t always clear to beginners. This article aims to explain these concepts clearly and highlight their differences with examples.

1. The Module

A module in Python is simply a file that contains Python code. This file has a .py extension and can include functions, classes, variables, and executable code. Modules allow you to reuse code by importing it into other files.

Example:

Let’s create a file math_utils.py:

<span># math_utils.py </span><span>def</span> <span>add</span><span>(</span><span>a</span><span>,</span> <span>b</span><span>):</span>
    <span>return</span> <span>a</span> <span>+</span> <span>b</span>
<span>def</span> <span>subtract</span><span>(</span><span>a</span><span>,</span> <span>b</span><span>):</span>
    <span>return</span> <span>a</span> <span>-</span> <span>b</span>
<span># math_utils.py </span><span>def</span> <span>add</span><span>(</span><span>a</span><span>,</span> <span>b</span><span>):</span>
    <span>return</span> <span>a</span> <span>+</span> <span>b</span>

<span>def</span> <span>subtract</span><span>(</span><span>a</span><span>,</span> <span>b</span><span>):</span>
    <span>return</span> <span>a</span> <span>-</span> <span>b</span>
# math_utils.py def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

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This module can then be imported and used in another script:

<span>from</span> <span>math_utils</span> <span>import</span> <span>add</span>
<span>result</span> <span>=</span> <span>add</span><span>(</span><span>5</span><span>,</span> <span>3</span><span>)</span>
<span>print</span><span>(</span><span>result</span><span>)</span>  <span># Outputs 8 </span>
<span>from</span> <span>math_utils</span> <span>import</span> <span>add</span>

<span>result</span> <span>=</span> <span>add</span><span>(</span><span>5</span><span>,</span> <span>3</span><span>)</span>
<span>print</span><span>(</span><span>result</span><span>)</span>  <span># Outputs 8 </span>
from math_utils import add

result = add(5, 3)
print(result)  # Outputs 8 

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2. The Package

A package is a folder containing multiple modules and a special file named __init__.py. This file allows Python to treat the folder as a package. Packages are used to organize code by grouping related modules.

Example:

Package structure:

math_tools/
    __init__.py
    algebra.py
    geometry.py
math_tools/
    __init__.py
    algebra.py
    geometry.py
math_tools/
    __init__.py
    algebra.py
    geometry.py

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• algebra.py:

<span>def</span> <span>solve_linear</span><span>(</span><span>a</span><span>,</span> <span>b</span><span>):</span>
    <span>return</span> <span>-</span><span>b</span> <span>/</span> <span>a</span>
<span>def</span> <span>solve_linear</span><span>(</span><span>a</span><span>,</span> <span>b</span><span>):</span>
    <span>return</span> <span>-</span><span>b</span> <span>/</span> <span>a</span>
def solve_linear(a, b):
    return -b / a

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• geometry.py:

<span>def</span> <span>area_circle</span><span>(</span><span>radius</span><span>):</span>
    <span>from</span> <span>math</span> <span>import</span> <span>pi</span>
    <span>return</span> <span>pi</span> <span>*</span> <span>radius</span> <span>**</span> <span>2</span>
<span>def</span> <span>area_circle</span><span>(</span><span>radius</span><span>):</span>
    <span>from</span> <span>math</span> <span>import</span> <span>pi</span>
    <span>return</span> <span>pi</span> <span>*</span> <span>radius</span> <span>**</span> <span>2</span>
def area_circle(radius):
    from math import pi
    return pi * radius ** 2

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Usage:

<span>from</span> <span>math_tools.algebra</span> <span>import</span> <span>solve_linear</span>
<span>from</span> <span>math_tools.geometry</span> <span>import</span> <span>area_circle</span>
<span>print</span><span>(</span><span>solve_linear</span><span>(</span><span>2</span><span>,</span> <span>-</span><span>4</span><span>))</span>  <span># Outputs 2.0 </span><span>print</span><span>(</span><span>area_circle</span><span>(</span><span>3</span><span>))</span>      <span># Outputs 28.27 </span>
<span>from</span> <span>math_tools.algebra</span> <span>import</span> <span>solve_linear</span>
<span>from</span> <span>math_tools.geometry</span> <span>import</span> <span>area_circle</span>

<span>print</span><span>(</span><span>solve_linear</span><span>(</span><span>2</span><span>,</span> <span>-</span><span>4</span><span>))</span>  <span># Outputs 2.0 </span><span>print</span><span>(</span><span>area_circle</span><span>(</span><span>3</span><span>))</span>      <span># Outputs 28.27 </span>
from math_tools.algebra import solve_linear
from math_tools.geometry import area_circle

print(solve_linear(2, -4))  # Outputs 2.0 print(area_circle(3))      # Outputs 28.27 

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3. The Library

The term library is often used to describe a collection of ready-to-use packages or modules. A library can contain several packages serving various purposes.

For example, Requests is a popular Python library for making HTTP requests. It includes several internal modules and packages working together to provide a user-friendly interface.

Example:

<span>import</span> <span>requests</span>
<span>response</span> <span>=</span> <span>requests</span><span>.</span><span>get</span><span>(</span><span>'</span><span>https://api.example.com</span><span>'</span><span>)</span>
<span>if</span> <span>response</span><span>.</span><span>status_code</span> <span>==</span> <span>200</span><span>:</span>
    <span>print</span><span>(</span><span>response</span><span>.</span><span>json</span><span>())</span>
<span>import</span> <span>requests</span>

<span>response</span> <span>=</span> <span>requests</span><span>.</span><span>get</span><span>(</span><span>'</span><span>https://api.example.com</span><span>'</span><span>)</span>
<span>if</span> <span>response</span><span>.</span><span>status_code</span> <span>==</span> <span>200</span><span>:</span>
    <span>print</span><span>(</span><span>response</span><span>.</span><span>json</span><span>())</span>
import requests

response = requests.get('https://api.example.com')
if response.status_code == 200:
    print(response.json())

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Note: Some people use the terms library and package interchangeably, and this confusion is understandable. The difference often lies in the scale and context of use.

4. The Framework

A framework is a structured library designed with a specific purpose. Unlike a simple library that provides tools, a framework enforces an architecture and a way of working. In Python, frameworks are commonly used for web development, data analysis, or artificial intelligence.

Example: Flask (Web Framework)

<span>from</span> <span>flask</span> <span>import</span> <span>Flask</span>
<span>app</span> <span>=</span> <span>Flask</span><span>(</span><span>__name__</span><span>)</span>
<span>@app.route</span><span>(</span><span>'</span><span>/</span><span>'</span><span>)</span>
<span>def</span> <span>home</span><span>():</span>
    <span>return</span> <span>"</span><span>Welcome to my website!</span><span>"</span>
<span>if</span> <span>__name__</span> <span>==</span> <span>'</span><span>__main__</span><span>'</span><span>:</span>
    <span>app</span><span>.</span><span>run</span><span>(</span><span>debug</span><span>=</span><span>True</span><span>)</span>
<span>from</span> <span>flask</span> <span>import</span> <span>Flask</span>

<span>app</span> <span>=</span> <span>Flask</span><span>(</span><span>__name__</span><span>)</span>

<span>@app.route</span><span>(</span><span>'</span><span>/</span><span>'</span><span>)</span>
<span>def</span> <span>home</span><span>():</span>
    <span>return</span> <span>"</span><span>Welcome to my website!</span><span>"</span>

<span>if</span> <span>__name__</span> <span>==</span> <span>'</span><span>__main__</span><span>'</span><span>:</span>
    <span>app</span><span>.</span><span>run</span><span>(</span><span>debug</span><span>=</span><span>True</span><span>)</span>
from flask import Flask

app = Flask(__name__)

@app.route('/')
def home():
    return "Welcome to my website!"

if __name__ == '__main__':
    app.run(debug=True)

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Flask imposes a minimalist structure but provides essential tools to develop a web application.

Summary of Differences

These distinctions are essential to better understand the Python ecosystem and organize your projects effectively. However, the boundary between some terms, such as library and package, can be blurry, and their usage may vary from person to person.

I am open to discussions and debates if you have a different perspective or points to add. Feel free to share your ideas or ask questions!

原文链接：Understanding Python Terminology: Module, Package, Library, and Framework