Python Programming Fundamentals

Data Structures

• Lists: ordered, mutable, and can store different data types
  • Indexing: access elements using square brackets [] and an index (starts at 0)
  • Slicing: extract a subset of elements using start:stop:step syntax
  • Methods: append(), insert(), extend(), remove(), pop(), sort(), reverse()
• Tuples: ordered, immutable, and can store different data types
  • Similar to lists, but cannot be modified after creation
• Dictionaries: unordered, mutable, and store key-value pairs
  • Access values using square brackets [] and a key
  • Methods: keys(), values(), items(), get(), update()
• Sets: unordered, mutable, and store unique elements
  • Methods: add(), remove(), union(), intersection(), difference()

File Input/Output

• Reading files:
  • open() function: opens a file and returns a file object
  • read() method: reads the entire file as a string
  • readline() method: reads a single line from the file
  • readlines() method: reads all lines from the file as a list of strings
• Writing files:
  • open() function: opens a file and returns a file object
  • write() method: writes a string to the file
  • writelines() method: writes a list of strings to the file
• Modes:
  • r : read mode (default)
  • w : write mode (truncates the file if it exists)
  • a : append mode (adds to the end of the file)
  • x : create mode (fails if the file already exists)
  • b : binary mode (for reading and writing binary files)

Exception Handling

• Try-except block:
  • try clause: code that might raise an exception
  • except clause: code to handle the exception
• Types of exceptions:
  • SyntaxError: syntax error in the code
  • NameError: undefined variable or function
  • TypeError: incorrect data type
  • IOError: input/output error
  • ValueError: invalid or unsupported value
• Raising exceptions:
  • raise statement: manually raises an exception
  • assert statement: raises an exception if the condition is false

Object-Oriented Programming

• Classes:
  • Define a blueprint for creating objects
  • Contain attributes (data) and methods (functions)
• Objects:
  • Instances of a class
  • Have their own set of attributes and methods
• Inheritance:
  • A child class inherits attributes and methods from a parent class
  • Can also override or extend parent class behavior
• Polymorphism:
  • Objects of different classes can be treated as objects of a common superclass
  • Methods can be overridden or overloaded to provide different behavior
• Encapsulation:
  • Hiding internal implementation details from the outside world
  • Accessing attributes and methods through a controlled interface