__slots__ — Easy Examples

Restricts instance attributes to a fixed set for memory savings

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Accessing __slots__

How to access and use __slots__.

python
# __slots__ restricts attribute creation for memory efficiency
class Point:
    __slots__ = ("x", "y")

    def __init__(self, x, y):
        self.x = x
        self.y = y

p = Point(1, 2)
print(p.x, p.y)

try:
    p.z = 3
except AttributeError as e:
    print(f"Cannot add: {e}")

__slots__ is a special attribute that restricts instance attributes to a fixed set for memory savings.

__slots__ in practice

Using __slots__ in everyday code.

python
# More __slots__ examples
print("__slots__ is a special Python attribute")

# Every object has certain dunder attributes
obj = object()
attrs = [a for a in dir(obj) if a.startswith("__")]
print(f"object has {len(attrs)} dunder attributes")

Understanding __slots__ helps you introspect and debug Python objects.

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