7.5 Finding modules

Python modules are the building blocks of code organization and reuse. They allow developers to extend Python's functionality beyond its built-in features. Understanding how to manage, import, and utilize modules is crucial for efficient programming.

From the Standard Library to third-party packages on PyPI, Python offers a vast ecosystem of modules. Navigating these resources, exploring module contents, and mastering import techniques are essential skills for every Python programmer. This knowledge empowers developers to leverage existing code and focus on solving unique problems.

Python Module Management

Python Standard Library vs PyPI

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• Python Standard Library provides built-in modules that come with Python installation offers a wide range of functionality for common programming tasks (

  [math](https://www.fiveableKeyTerm:Math)

  ,

  [random](https://www.fiveableKeyTerm:Random)

  ,

  os

  ,

  [datetime](https://www.fiveableKeyTerm:datetime)

  )
• Python Package Index (PyPI) serves as a repository of third-party packages and modules allows developers to share and distribute their own packages extends the functionality of Python beyond the Standard Library (

  numpy

  ,

  pandas

  ,

  requests

  ,

  flask

  )
  • Packages on PyPI can be installed using package managers like

    [pip](https://www.fiveableKeyTerm:pip)

Navigation of python.org and pypi.org

• python.org provides access to the official Python documentation allows exploration of the Standard Library reference to find built-in modules
  • Read module descriptions, usage examples, and API references to evaluate the suitability of a module for a specific task based on its documentation
• pypi.org enables searching for third-party packages using keywords or package names
  • Review package descriptions, documentation, and user ratings to assess the package's popularity, maintenance, and community support
  • Check package dependencies and compatibility with your Python version and evaluate the package's license and terms of use

Module exploration and import functions

• Importing modules from the Standard Library
  1. Use the

     import

     statement to import a module:

     import module_name

  2. Access module functions or variables using dot notation:

     module_name.function_name()

  3. Alternatively, use

     from module_name import function_name

     to import specific functions
     • Example:

       import math

       , then use

       math.sqrt(16)

       to calculate the square root of 16
• Importing modules from PyPI
  1. Install the package using

     pip

     in the command line:

     pip install package_name

  2. Import the installed package in your Python script:

     import package_name

  3. Use the package's functions and classes as per its documentation
     • Example:

       import numpy as np

       , then use

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

       to create a NumPy array
• Exploring modules

  • [dir()](https://www.fiveableKeyTerm:dir())

    function lists all available functions and variables in a module

  • [help()](https://www.fiveableKeyTerm:help())

    function accesses the module's documentation:

    help(module_name)

    • Inspect a specific function's documentation:

      help(module_name.function_name)

    • Example:

      dir(math)

      lists all functions in the

      math

      module, and

      help(math.sqrt)

      views the documentation for the

      sqrt()

      function

Advanced Module Management

• Virtual environments: Isolated Python environments for project-specific dependencies
• Dependency management: Tools like

  pip

  to manage package versions and dependencies
• Module search path: Python's system for locating modules (including the

  PYTHONPATH

  environment variable)

• [__init__.py](https://www.fiveableKeyTerm:__init__.py)

  : Special file that defines a directory as a Python package
• Wheel files: Pre-built package format for faster installation of Python libraries