Importing Modules

In Python, modules allow you to organize and reuse your code. A module is simply a .py file that contains functions, classes, or variables that you can use in other programs. Importing modules is a fundamental practice for writing clean, maintainable, and scalable code.

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Why Import Modules?

• Reuse: Use already written functions and classes, avoiding repeated code.
• Organization: Divide your project into smaller, more manageable files.
• Access to tools: Take advantage of Python’s vast standard library and external packages.

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Importing Standard Modules

Python includes a large number of ready-to-use modules. For example, to work with dates you can import the datetime module:

Importing a Standard Module

import datetime

today = datetime.date.today()
print('Today's date is:', today)

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Importing Specific Functions or Classes

You can import only what you need from a module:

Importing a Specific Function

from math import sqrt

print(sqrt(16))  # 4.0

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Renaming Modules Upon Import

Sometimes an alias is used to shorten the module name:

Importing with Alias

import numpy as np

array = np.array([1, 2, 3])
print(array)

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Importing Your Own Modules

If you have a file named utilities.py in your project, you can import it like this:

Importing a Custom Module

import utilities

utilities.my_function()

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Best Practices

• Import only what you need.
• Use aliases (as) for long or common names.
• Keep your imports at the beginning of the file.

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Summary

• Modules help you organize and reuse code in Python.
• You can import standard, external, or custom modules.
• Use the different forms of import according to your needs.

Ready to test? Try importing the random module and generate a random number.