Python Modules

Introduction

• Modules are files containing Python code.
• They help organize code logically and enable code reuse.

The import Statement

• Use import to include a module.
• Syntax:

  import module_name
  

• Example:

  import sys
  print(sys.argv)
  

from ... import Statement

• Import specific attributes from a module.
• Syntax:

  from module_name import attribute_name
  

• Example:

  from math import sqrt
  print(sqrt(16))
  

as Keyword

• Alias module or attribute names.
• Syntax:

  import module_name as alias
  

• Example:

  import math as m
  print(m.sqrt(16))
  

Built-in Modules

• Python includes many useful built-in modules.
• Examples: sys, os, time, math, csv, random, re, datetime, and more...

Writing Modules

• Create a mymodule.py file with functions and variables.

  def say_hi():
      print('Hello!')
  

• Usage:

  import mymodule
  mymodule.say_hi()
  

__name__ Attribute

• Check if a module is run directly or imported.
• Example:

  if __name__ == "__main__":
      # This block runs only when the module is executed directly
      print("Module is run directly")
  else:
      print("Module is imported")
  

• You won't see this in Google Colab, but you will if you start writing Python for things like games and web apps.

JSON

• Encode and decode JSON data.
• Example:

  import json
  
  data = {'name': 'Alice', 'age': 25}
  json.dumps(data)
  

  '{"name": "Alice", "age": 25}'
  

PPrint

• Pretty print data structures.
• Example:

  from pprint import pprint
  
  data = {'name': 'Alice', 'age': 25}
  pprint(data)
  

  {'age': 25,
   'name': 'Alice'}
  

Datetime

• Work with dates and times.
• Example:

  from datetime import datetime  # This one is weird
  
  now = datetime.now()
  
  hp_birthday = datetime(1980, 7, 31)
  hp_seconds_alive = (now - hp_birthday).total_seconds()
  

Summary

• Modules help organize and reuse code.
• Use import, from ... import, and as to work with modules.
• Built-in and custom modules enhance functionality.

Exercise

http://gg.gg/1b8kph