Managing Imports¶

Python modules are reusable pieces of code that allow you to logically organize your programs. Modules can define functions, classes, and variables, or include runnable code. Using the import statement, you can include these modules in your scripts, accessing their functionality without rewriting code.

Syntax¶

To import a module, use the import statement. Here are a few examples:

import math  # Imports the entire math module
from collections import Counter  # Imports only the Counter class from the collections module
import numpy as np  # Imports the numpy module and gives it an alias as np

Examples¶

Example 1: Using the os Module¶

The os module provides functions for interacting with the operating system, such as managing files and directories.

import os

# Get the current working directory
current_directory = os.getcwd()
print(f"Current Directory: {current_directory}")

# List files and directories in the current directory
entries = os.listdir(current_directory)
print(f"Contents of Directory: {entries}")

# Create a new directory
os.mkdir('example_dir')
print("Created a new directory named 'example_dir'")

Example 2: Using the math Module¶

The math module provides access to mathematical constants and functions.

import math

# Calculate the square root of a number
number = 16
sqrt_number = math.sqrt(number)
print(f"The square root of {number} is {sqrt_number}")

# Calculate the value of pi
print(f"The value of pi is {math.pi}")

# Calculate the sine of an angle (in radians)
angle = math.radians(30)  # Convert degrees to radians
sine_value = math.sin(angle)
print(f"The sine of 30 degrees is {sine_value}")

Importing Specific Functions or Classes¶

To avoid prefixing module names every time, import specific components directly:

from math import sqrt, pi

# Using imported functions directly
print(f"The square root of 25 is {sqrt(25)}")
print(f"The value of pi is approximately {pi}")

Aliasing Modules¶

For long module names or commonly used libraries, aliasing makes code more concise and readable.

import numpy as np

# Create an array using numpy
array = np.array([1, 2, 3, 4, 5])
print(f"Numpy Array: {array}")

Best Practices¶

1. Organize imports at the top of the file: All imports should be placed at the beginning of the script for clarity and maintainability.
2. Avoid wildcard imports: Instead of from module import *, import only the components you need for clarity and to avoid conflicts.
3. Use aliases for readability: For example, import numpy as np.
4. Group imports logically:
   • Standard library imports (e.g., math, os).
   • Third-party library imports (e.g., numpy, pandas).
   • Custom module imports.

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