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Importing Modules

This note covers importing modules in Python.

Modules are files containing Python definitions and statements. They provide a way to organize and reuse code.

Ways to Import:

import module_name: Imports the entire module. Access members using module_name.member.
from module_name import member_name: Imports a specific member (function, class, variable). Access directly using member_name.
from module_name import member1, member2: Imports multiple specific members.
from module_name import *: Imports all members. Generally discouraged due to potential naming conflicts. (Namespaces and Scope)

Example:

import math

print(math.sqrt(25))  # Output: 5.0

from random import randint

print(randint(1, 10)) # Output: A random integer between 1 and 10 (inclusive)

from os import path, getcwd

print(getcwd()) #Prints current working directory.

Module Search Path:

Python searches for modules in a specific order:

The current directory.
Locations specified by the PYTHONPATH environment variable.
Standard library directories.
Installation-specific directories (site-packages).

(PYTHONPATH Environment Variable)

Packages:

Packages are a way to organize modules into directories. A package directory must contain an __init__.py file (can be empty).

# mypackage/
#  __init__.py
#  module1.py
#  module2.py

import mypackage.module1
import mypackage.module2 
from mypackage import module1, module2

(Packages and init.py)

Relative Imports:

Within a package, you can import modules relative to the current module’s location. Use leading dots to specify the relative path.

# mypackage/module1.py
from .module2 import my_function # Imports my_function from module2 within mypackage

(Relative Imports)

Built-in Modules:

Python comes with many built-in modules (e.g., math, os, random, sys). These are always available without needing to install them.

(Standard Library Modules)

Importing Modules

Carson West

Python 1 Home

Importing Modules