Variables & Data Types

Python is dynamically typed — you don't declare types, Python infers them.

Basic types:

name = "Alice"        # str
age = 30              # int
height = 5.9          # float
is_student = True     # bool
nothing = None        # NoneType

Check the type:

type(age)    # <class 'int'>

Type conversion:

int("42")      # 42
str(100)       # "100"
float("3.14") # 3.14
bool(0)        # False

Naming rules: lowercase_with_underscores (snake_case). No spaces. Can't start with a number. Case-sensitive.

Constants: By convention, use ALL_CAPS: MAX_SIZE = 100. Python doesn't enforce immutability, it's just a signal.

Reference:

Wikipedia: Python

https://en.wikipedia.org/wiki/Python_(programming_language)