Abstract Class

OOP/abstract_class.ipynb

@@ -0,0 +1,273 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "3afa5dd3-247a-4330-98e9-79bf52554c06",
+   "metadata": {},
+   "source": [
+    "## You have to implement area()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "77136081-d4fc-4ed4-8175-7a4956b4af0f",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Square area: 25\n",
+      "Circle area: 28.259999999999998\n"
+     ]
+    }
+   ],
+   "source": [
+    "from abc import ABC, abstractmethod\n",
+    "\n",
+    "class Shape(ABC):  # Abstract base class for shapes\n",
+    "  @abstractmethod\n",
+    "  def area(self):\n",
+    "    pass  # Abstract method, subclasses must implement\n",
+    "\n",
+    "class Square(Shape):  # Concrete subclass of Shape\n",
+    "  def __init__(self, side):\n",
+    "    self.side = side\n",
+    "\n",
+    "  def area(self):\n",
+    "    return self.side * self.side\n",
+    "\n",
+    "class Circle(Shape):  # Concrete subclass of Shape\n",
+    "  def __init__(self, radius):\n",
+    "    self.radius = radius\n",
+    "\n",
+    "  def area(self):\n",
+    "    return 3.14 * self.radius * self.radius\n",
+    "\n",
+    "# Trying to create a Shape instance directly will fail\n",
+    "# since it's an abstract class\n",
+    "# shape = Shape()  # TypeError: Can't instantiate abstract class Shape with abstract methods area\n",
+    "\n",
+    "square = Square(5)\n",
+    "circle = Circle(3)\n",
+    "\n",
+    "print(f\"Square area: {square.area()}\")\n",
+    "print(f\"Circle area: {circle.area()}\")\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "fdad0d0e-0185-4464-9371-7df90159e42f",
+   "metadata": {},
+   "source": [
+    "### You can't skip implementation"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "2c5db76b-ed42-47fd-8ee7-c33cc129d826",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Can't instantiate abstract class Triangle with abstract methods area\n"
+     ]
+    }
+   ],
+   "source": [
+    "class Triangle(Shape):\n",
+    "    pass\n",
+    "\n",
+    "try:\n",
+    "    t = Triangle()\n",
+    "except TypeError as error:\n",
+    "    print(error)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "48e01ee7-1655-4769-8915-9dc5e328600c",
+   "metadata": {},
+   "source": [
+    "### but you can pass it again with pass"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "43457ae6-bf75-49d8-9105-3936ff031fee",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "None\n"
+     ]
+    }
+   ],
+   "source": [
+    "class Square(Shape):  # Concrete subclass of Shape\n",
+    "  def area(self):\n",
+    "    pass\n",
+    "\n",
+    "s = Square()\n",
+    "print(s.area())"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "740b1c0b-5665-4f72-a1b8-6cf6637c427d",
+   "metadata": {},
+   "source": [
+    "### and you can't instantiate the base class"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "5d9d558a-6563-4ba8-8d8d-7442a36482cc",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Can't instantiate abstract class Shape with abstract methods area\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    s = Shape()\n",
+    "except TypeError as error:\n",
+    "    print(error)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "d892541c-818b-4639-aeda-61d6de159ee1",
+   "metadata": {},
+   "source": [
+    "## And you can register subclasses to be like a virtual base class (Godfather to them)\n",
+    "### Adobted kids, not DNA kids"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "3837f4b3-2c40-4a67-a626-7e888900924a",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "float"
+      ]
+     },
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "import abc\n",
+    "class Double(metaclass=abc.ABCMeta):\n",
+    "    \"\"\"Double precision floating point number.\"\"\"\n",
+    "    pass\n",
+    "\n",
+    "Double.register(float)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "id": "b239d976-8b37-4a7b-be9e-7ad11458b061",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "True"
+      ]
+     },
+     "execution_count": 6,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "issubclass(float, Double)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "id": "5ea12601-9d55-460b-832b-cfb23f5e37b9",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "True"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "isinstance(1.2345, Double)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "0dc639a4-0c21-448e-9c0f-534e8fc2de6f",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "True\n"
+     ]
+    }
+   ],
+   "source": [
+    "@Double.register\n",
+    "class Double64:\n",
+    "    \"\"\"A 64-bit double-precision floating-point number.\"\"\"\n",
+    "    pass\n",
+    "\n",
+    "print(issubclass(Double64, Double))  # True"
+   ]
+  }
+ ],
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+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
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+   "mimetype": "text/x-python",
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+}