Python @property decorator

1) Simple @property

Create a class Person with a private attribute _name. Use @property so p.name returns the value.

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2) Property With Setter

Extend the above so you can assign to p.name = "Alice" using a @name.setter.

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3) Read-Only Property

Create a class Circle with private _radius. Add a read-only property radius (no setter).

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4) Computed Property

In Circle, add a property area that returns π × r² (use math.pi).

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5) Property With Validation

Create a class Student with private _age. In the setter for .age, ensure age ≥ 0; if not, print an error.

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6) Property That Formats

Create a class Person where .fullname returns "First Last". Store first and last privately.

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7) Auto-Compute Property

Add a class Rectangle with _width and _height. Add property perimeter that returns 2 × (w + h).

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8) Property Without Setter

Create a class Temperature with private _celsius. Only allow reading .celsius — no setter.

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9) Write-Only Property

Create a property password with only a setter; store hashed or just print “Set!”

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10) Lazy Computed Property

Create a property in a class that prints “Computing…” the first time it’s read.

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11) Property That Counts Access

Create a property that increments a counter each time it is accessed.

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12) Property Using Different Internal Name

Store _x but expose .value as property (both get/set).

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13) Protected Setter

Make .age set only if value is an integer; otherwise ignore.

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14) Property Returning List Length

Given class with a private list _items, add property .count that returns its length.

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15) Property That Uppercases

Property name returns uppercase form of the internal string.

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16) Property With Print

Every time the property is accessed, print “Accessing…”.

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17) Property That Prevents Negative

Given class with _balance, setter for .balance prevents negative values.

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18) Property That Logs Change

Setter for .score prints old and new value whenever .score = … is assigned.

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19) Chained Properties

Create Point class with .x and .y properties backed by _x, _y.

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20) Property to Upper/Lower

Given class with internal _text, create two properties:

• .upper returns uppercase

• .lower returns lowercase

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🧠 Concepts Covered

Feature	Practice
Defining properties	@property def name
Setters	@name.setter
Read-only properties	no setter
Computed values	value derived from internals
Validation inside setter	control assignment
Side effects	printing/logging when accessed

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📌 Minimal Starter Template

class Person:
    def __init__(self, name):
        self._name = name

    @property
    def name(self):
        return self._name

    @name.setter
    def name(self, value):
        self._name = value

p = Person("Alice")
print(p.name)  # uses property
p.name = "Bob" # uses setter
print(p.name)

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📝 Quick Tips

• Use private attribute naming (e.g., _x) for backing store.

• @property makes a method look like a field.

• You can define getters, setters, and deleters with decorators.

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