Data Types & None

Basic data types

You'll need these four every day.

name = "John"       # str
age = 25             # int
price = 99.50        # float
is_active = True     # bool
is_admin = False      # bool

Notice the capitalization difference from JS/TS:

None

Python's equivalent of null is None:

user = None

You'll see this constantly in backend code (for example FastAPI). To check it:

if user is None:
    print("User not found")

For now, just remember: None means "no value". We'll cover is properly later.

Checking a type

Python has a built-in type() function:

name = "John"
age = 25

print(type(name))   # <class 'str'>
print(type(age))    # <class 'int'>

You can also check a type with isinstance():

isinstance(age, int)   # True