What's the pythonic way to use getters and setters?

python

best-practices

properties

pythonic-way

byNikita Barsukov·Sep 12, 2024

Embrace Pythonic convention by leveraging the @property decorator for getters and @<property_name>.setter for setters. This idiosyncrasy promotes native attribute access while ensuring encapsulation.

class MyClass:
    def __init__(self):
        self._my_attribute = None                                                        # It's private! Keep out! 🚷

    @property
    def my_attribute(self):
        """Getter for my_attribute"""
        return self._my_attribute

    @my_attribute.setter
    def my_attribute(self, value):
        """Setter for my_attribute"""
        if isinstance(value, int) and value > 0:                                         # Hey, no funny business here!
            self._my_attribute = value
        else:
            raise ValueError("Value must be a positive integer! 🥵")

obj = MyClass()
obj.my_attribute = 10  # Setter called here! Knock knock! 🚪
print(obj.my_attribute)  # Getter called here! Peekaboo! 👀

This pattern allows for smooth attribute operation, cleverly enclosing the logic with an intuitive syntax.

Python properties: Under the hood

Making variables private

Prefix attribute names with underscore (_) indicating private variables. This convention communicates to others that the variable shouldn't be accessed directly.

Ensuring data integrity

Setters employ type checks and validations, flagging ValueError or custom exceptions for invalid inputs, which prevents misuse of the class interface.

Documenting properties

Docstrings explain the purpose behind a property and any side-effects of getting or setting a value, aiding in code readability and maintainability.

Use direct access when necessary

If simple attribute access is sufficient and there is no validation or computation necessary, we can bypass property usage.

Embracing read-only properties

Use @property without a corresponding setter to enforce read-only attributes, safeguarding against unintended mutations.

Deletion control with `@<property_name>.deleter`

Apply this decorator when removing an attribute needs specific handling.

Consistent naming

Maintain clarity in your code by using consistent naming for the getter, setter and deleter.

Upping your property game

Observering pattern with properties

Properties allow triggering callbakcs on value changes, paving the path for observer pattern.

Memory optimization with `slots`

Use __slots__ to streamline memory usage, particularly when your class will have a plentiful number of instances.

Metaprogramming and properties

For complex cases, employ metaclasses and descriptors to mechanize or customize property behaviors.

Bolstering security

Properties provide a layer of security, allowing controlled manipulation of sensitive data, a crucial aspect in designing public APIs.

explain-codes / Python / What's the pythonic way to use getters and setters?

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