Python Basics

Syntax

• Indentation: Python uses indentation (spaces or tabs) to define block-level structure.
• Variables: Assign a value to a variable using the assignment operator (=).
• Basic Data Types:
  • Integers (int): whole numbers
  • Floats (float): decimal numbers
  • Strings (str): sequences of characters, can be enclosed in single quotes or double quotes
  • Boolean (bool): true or false values
• Operators:
  • Arithmetic operators: +, -, *, /, %
  • Comparison operators: ==, !=, >, <, >=, <=
  • Logical operators: and, or, not
• Control Flow:
  • Conditional statements: if, elif, else
  • Loops: for, while
  • Functions: def

Modules and Packages

• Modules: A file containing Python definitions and statements.
• Packages: A directory containing multiple modules and a special file __init__.py.
• Importing Modules:
  • Import a module: import module_name
  • Import a specific function or variable: from module_name import function_or_variable
  • Import all functions and variables: from module_name import * (not recommended)
• Creating a Module:
  • Create a new Python file with a .py extension.
  • Define functions, variables, and classes in the file.
  • Import the module in another Python file using import statement.

Object-Oriented Programming

• Classes: Define a class using the class keyword.
• Objects: Instances of a class, created using the () operator.
• Attributes: Data associated with an object, accessed using dot notation (e.g., object.attribute).
• Methods: Functions associated with a class, accessed using dot notation (e.g., object.method()).
• Inheritance: A child class can inherit attributes and methods from a parent class using the class Child(Parent): syntax.

File Input/Output

• Reading Files:
  • Open a file in read mode: open('file.txt', 'r')
  • Read the contents: file.read() or file.readline() or file.readlines()
  • Close the file: file.close() (or use with statement)
• Writing Files:
  • Open a file in write mode: open('file.txt', 'w')
  • Write to the file: file.write('content')
  • Close the file: file.close() (or use with statement)
• Modes:
  • 'r': read mode
  • 'w': write mode
  • 'a': append mode
  • 'r+', 'w+', 'a+': read and write modes
• JSON and CSV:
  • Use the json module to work with JSON data.
  • Use the csv module to work with CSV data.

Syntax in Python

• Python uses indentation to define block-level structure, which can be done using spaces or tabs.

Variables in Python

• Assign a value to a variable using the assignment operator (=).

Basic Data Types in Python

• Integers (int) are whole numbers.
• Floats (float) are decimal numbers.
• Strings (str) are sequences of characters and can be enclosed in single quotes or double quotes.
• Boolean (bool) values are either true or false.

Operators in Python

• Arithmetic operators include +, -, *, /, and %.
• Comparison operators include ==, !=, >, and <=.