One of Python's most fundamental design principles is that everything is an object. This isn't just a philosophical statement—it has practical implications for how Python code works and what's possible with the language.
The built-in type() function reveals the class of any value:
print(type(42)) # <class 'int'>
print(type(3.14)) # <class 'float'>
print(type("hello")) # <class 'str'>These aren't just labels. int, float, and str are actual classes, and the values 42, 3.14, and "hello" are instances of those classes.
Literals Are Instances
Python's syntax for literals—writing 5 instead of int(5)—is a convenience provided by the interpreter. During compilation, these are equivalent:
x = 5
x = int(5)The implication is significant: integers, floats, strings, and other "primitive" types are not special cases. They're objects with methods and attributes, just like any user-defined class.
This uniformity is what enables Python's flexibility. Understanding it unlocks more advanced features like operator overloading, metaclasses, and the descriptor protocol.