Python Basics

Variables and Data Types

• In Python, a variable is a name given to a value.
• Variables can store different data types, including:
  • Integers (int): whole numbers, e.g. 1, 2, 3
  • Floats (float): decimal numbers, e.g. 3.14, -0.5
  • Strings (str): sequences of characters, e.g. "hello", 'hello' (note: strings can be enclosed in single or double quotes)
  • Boolean (bool): true or false values
  • Lists (list): ordered collections of values, e.g. [1, 2, 3], ["a", "b", "c"]
  • Tuples (tuple): ordered, immutable collections of values, e.g. (1, 2, 3), ("a", "b", "c")
  • Dictionaries (dict): unordered collections of key-value pairs, e.g. {"name": "John", "age": 30}

Operators and Control Structures

• Arithmetic operators:
  • Addition: a + b
  • Subtraction: a - b
  • Multiplication: a * b
  • Division: a / b
  • Modulus: a % b
  • Exponentiation: a ** b
• Comparison operators:
  • Equal: a == b
  • Not equal: a!= b
  • Greater than: a > b
  • Less than: a < b
  • Greater than or equal to: a >= b
  • Less than or equal to: a <= b
• Logical operators:
  • And: a and b
  • Or: a or b
  • Not: not a
• Control structures:
  • Conditional statements: if, elif, else
  • Loops: for, while

Functions

• Functions are blocks of code that can be called multiple times with different inputs.
• Functions can take arguments, which are values passed to the function when it is called.
• Functions can return values, which can be used by the calling code.
• Functions can be defined with the def keyword, e.g. def greet(name): print("Hello, " + name + "!")

Modules and Packages

• Modules are pre-written code libraries that can be imported into a Python script.
• Modules can be imported using the import statement, e.g. import math
• Packages are collections of modules that can be imported together.
• Packages can be imported using the import statement, e.g. import tkinter as tk

Object-Oriented Programming

• Classes define objects and their properties and behaviors.
• Classes can inherit properties and behaviors from parent classes.
• Objects are instances of classes, and can have their own properties and behaviors.
• Objects can be created using the () operator, e.g. my_object = MyClass()