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Intro to Python Libraries & modules

SJU ACM STUDENT CHAPTER

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before we start…

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important Reminders:

This lab will involve the use of python and visual Studio Code (VSCode/VSC), both throughout the presentation and the code-along lab at the end.
If you do not have python and/or vscode set up on your machine, the following will be a guide on how to set up python and vscode.

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Python/vscode set up

Step one:

Check if you have python on your machine

windows: press win+R, type in cmd, and command prompt should popup up. type in ‘py —version’
Mac os: launch terminal, type in ‘python3 —version’

If not on your machine, proceed to step two

Step two:

visit python.org/downloads, click ‘download python 3.12.2 (this is the latest major release)
Follow all on-screen instructions on python setup wizard

maintain all default settings

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Python/vscode set up cont.

Step three

visit code.visualstudio.com

windows: click download button
macos: click the arrow next to download button, and download mac os stable release

Step four:

follow on-screen instructions on vscode setup wizard

notes:

you will get an option to create a desktop icon, i recommend you check that box
once the installation process finishes, ensure to check the box to launch vscode

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Python/vscode set up cont.

Step five

once inside vscode, customize your experience to your liking (this can be changed later)

for now, ensure you select the color theme you want

Step six:

on the left hand side, there is a menu with seven icons (five on the top half, two on the bottom half)
click on the last icon in the top half of the menu (extensions)

step seven:

Once inside extensions, you will search for two things that you need to download:

python (should be in the popular section)
Code Runner (helps you run your code)

install both, and you should be set!

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Primer on python

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Primer on python

Python is a high-level, general-purpose programming language.

It is dynamically-typed and garbage-collected.
Known for clear syntax, readability, flexibility, and indentation.
Supports multiple programming paradigms:

Structured, oop and functional programming

Fast Facts:

Creator: GUido van rossum
First release: february 20th, 1991
latest release: python 3.12.2 (february 6th, 2024)

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Primer on python cont.

Python is known for its comprehensive standard library.

As a result, Python is said to be a “batteries included” language.
it provides broad functionality, with a vast number of modules and packages that support a variety of tasks.
Eliminates need for external dependencies.
Included with every python installation!

Examples:

text processing, data types, math, file/directory access, etc.

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Basics of modules and libraries

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What Are modules?

A module in python is a file containing python definitions and statements.
Can define functions, classes, and variables that can be used in other python files.
Typically used to break down large programs and tasks into small and manageable files.
Two types of modules:

user-defined modules
built-in modules

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user-defined modules

How to create your own module:

First, create a new file, and name it appropriately. Ensure it ends in .py.
Next, define a function, class, variable, etc.
Then, in a new file, use the ‘import’ keyword on the first line of code.

you are able to rename the module whatever you want in the new file.

Finally, access the function(s) you desire using the following syntax:

module_name.function_name

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Built-in modules

Python comes equipped with a library of standard modules.

over 200 modules in the library
Some are built into the interpreter, others are not.
Most modules are available to users, but some are designed for specific operating systems/platforms/software.

winreg, Winsound: Designed for windows
posix, pwd, syslog: designed for unix/linux

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Examples of most-often used modules

provides way to use os-dependent functionality, e.g. navigating file system

used to manipulate the python runtime environment

datetime

supplies classes for manipulating dates & time, essential for time-based ops

math

offers access to mathematical functions

random

provides tools for random selections

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What are Libraries?

In short, a library in python is an umbrella term that refers to a reusable chunk of code.

Typically consists of a collection of related modules and packages
In other words, libraries are a collection of packages.

Libraries help devs share reusable code with the community.

This eliminates the need to write code from scratch, which is very useful for large-scale projects!
This is done by creating a set of functions that are related to the same area.

Fun fact:

There currently are over 137,000 python libraries!

rookie numbers!

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Popular python libraries

Data Analysis & Science:

Pandas & Numpy: Data structures, data analysis, math functions

Machine Learning & Ai:

Tensorflow & Pytorch: flexibility, speed, efficiency in ML & AI Development

Data visualization:

matplotlib & seaborn: high-level interfaces for visualizing and drawing statistical graphics

Scientific computing:

Scipy & sumpy: Science computing, algorithms, & mathematical tools

Networking & Internet:

requests & Beautiful soup: Http library, web scraping

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What are packages?

packages in python are directories of a collection of modules

Packages allow for hierarchical structuring of the module namespace.
In the same way we organize our files into folders and subfolders on a hard drive, we can organize modules into packages and subpackages.

Each package must include an initialization file for it to be considered a package.

file name: ‘__init__.py’

Fun fact:

there are over 497,000 python packages, according to pypistats.org (as of 2/14/2024)

ALL-pro numbers!

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popular packages

Numpy/pandas

Previously mentioned; are package/library hybrids

pytest

Provides a variety of modules to test new code.

incl. small unit/complex functional tests

Boto3/botocore

these are part of the amazon web services software development kit (AWS SDK).
makes it easy to integrate python with aws services!

The recommended tool for installing python packages

Setuptools

helps to easily download, build, install, upgrade, and uninstall python packages.
requires a few dependencies for it to work

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what are frameworks?

Frameworks in python are a special collection of modules and packages that help programmers fast track the development process.

Usually more complex than libraries
Contain packages that perform specific operations

Basic flow & architecture of application

Analogy of house construction:

python frameworks provide you with all the essential building blocks of construction

Foundation, walls, windows, roof, etc.

Then, devs build the application around the foundation and add furniture, appliances, etc.

Three types of frameworks:

full-stack
micro
asynchronous

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types of frameworks

Full-stack:

have all web dev requirements

form generators, form validation, template layouts
Core features of any full-stack framework

Micro

Require lots of code and additional requirements to be added manually

doesn’t provide the specific tools provided by full-stack frameworks

Asynchronous

supports high concurrency

large set of concurrent connections

uses asyncio library to run the process

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popular frameworks

Flask

A micro framework through which devs can build a solid web app foundation from

lightweight/modular design, readily adaptable

Django

A Full-stack framework, known for helping develop rich web apps

built-in libraries, free-to-use features, database support

bottle

A micro framework, creates a single source file for every developed app

Api dev, no dependencies, built-in https server, database support

Cherrypy

Open-source, OOP, micro framework

one of the oldest python Frameworks
runs on android, flexibility, robust configuration system, etc

falcon

A micro framework used to build web apis

needs dependencies, used widely at linkedin, openstack, etc.
upfront exception handling, highly optimized code base, extensible

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Knowing the difference

Packages and libraries are often used interchangeably. However, it is important to understand the difference between them.
Generally speaking:

A package is a collection of modules
A library is a collection of packages

All of the terms discussed so far (Function, module, package, library, and framework) are ultimately cogs working together, hand-in-hand, to create an application.

source: Swathi arun, https://medium.com/pythoneers/6-must-know-words-in-python-ac87ab420ab7