Python Modules
Python modules are files that store functions, classes, and variables. Python has numerous built-in modules, each specialized for various tasks. In this guide, we’ll cover how to create and use modules in Python, including importing techniques, specific imports, aliasing, and exploring built-in modules.
What is a Python Module?
A Python module is a file containing definitions and statements. Modules help organize code logically, making it more understandable and reusable. Each module can define functions, classes, and variables, and it may include executable code.
Creating a Python Module
To create a module in Python, write the necessary code and save it with a .py extension. Here’s a simple example:
Example: operations.py
# Module: operations.py
def add(a, b):
return a + b
def subtract(a, b):
return a - bTo use the functions and classes defined in a module, we can import it using the import statement. Python searches for modules in a specific order and imports them if found in the search path.
Syntax:
import module_nameExample:
import operations
print(operations.add(15, 5))Output:
20Python’s from statement allows you to import specific parts of a module rather than the whole module.
Example:
# Importing specific functions from math
from math import sqrt, factorial
print(sqrt(25))
print(factorial(5))Output:
5.0
120Using the * symbol imports all names from a module into the current namespace. Use this approach cautiously to avoid conflicts.
Syntax:
from module_name import *Example:
from math import *
print(sqrt(16))
print(factorial(4))Output:
4.0
24When importing a module, Python looks through the following paths:
1. Current directory.
2. Directories listed in PYTHONPATH (an environment variable).
3. Installation-specific directories.
Python stores these paths in sys.path for easy access.
import sys
print(sys.path)Example Output:
['/user/files', '/usr/lib/python3.8', ...]Renaming a Module with Aliases
You can rename a module upon import using the as keyword.
Syntax:
import module_name as alias_nameExample:
import math as m
print(m.sqrt(25))
print(m.factorial(4))Output:
5.0
24Python provides several built-in modules, including math, random, and datetime. Let’s look at a few examples:
Example with math
import math
print(math.sqrt(36))
print(math.pi)
print(math.degrees(1.57))
print(math.radians(90))
print(math.sin(1.57))
print(math.factorial(5))Output:
6.0
3.141592653589793
90.0
1.5707963267948966
1.0
120Example with random
import random
print(random.randint(1, 10)) # Random integer between 1 and 10
print(random.uniform(0, 1)) # Random float between 0 and 1
print(random.choice(['apple', 'banana', 'cherry']))Output:
7
0.5682323
bananaExample with datetime:
import datetime
from datetime import date
import time
print(time.time())
print(date.fromtimestamp(123456789))Output:
1698257896.47832
1973-11-29