OOP Instance, Class, Static Methods.ipynb

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    "# OOP\n",
    "\n",
    "## Instance methods\n",
    "\n",
    "These are the normal methods you usually see in Python classes. They carry no special decorators.\n",
    "They can access an instance's properties, which are preceded by the self keyword."
   ]
  },
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   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hello, World!\n",
      "I'm an instance method!\n",
      "My name is Decorator_Example\n"
     ]
    }
   ],
   "source": [
    "class MethodExample:\n",
    "    def __init__(self):\n",
    "        print(\"Hello, World!\")\n",
    "        self.name = 'Decorator_Example'\n",
    "    def example_function(self):\n",
    "        print('I\\'m an instance method!')\n",
    "        print('My name is ' + self.name)\n",
    "    \n",
    "ex = MethodExample()\n",
    "ex.example_function()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Class methods\n",
    "\n",
    "These belong to the class level. They can access and even alter class variables. Unlike static methods, these do have access to the rest of the class to which they belong but instance level properties are invisible to them. They must be marked with the @classmethod decorator to act as such."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
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   "source": [
    "class MethodExample:\n",
    "    clsVar = \"Potato\"\n",
    "    def __init__(self):\n",
    "        print(\"Hello, World!\")\n",
    "        self.name = 'Decorator_Example'\n",
    "    def example_function(self):\n",
    "        print('I\\'m an instance method!')\n",
    "        print('My name is ' + self.name)\n",
    "        \n",
    "    @classmethod\n",
    "    def ex_cls_method(cls):\n",
    "        print(\"I'm a class method\")\n",
    "        cls.example_function(cls)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hello, World!\n",
      "I'm a class method\n",
      "I'm an instance method!\n"
     ]
    },
    {
     "ename": "AttributeError",
     "evalue": "type object 'MethodExample' has no attribute 'name'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-16-cb33932ba456>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[0mex\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mMethodExample\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 2\u001b[1;33m \u001b[0mex\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mex_cls_method\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;32m<ipython-input-15-9160b7733cf5>\u001b[0m in \u001b[0;36mex_cls_method\u001b[1;34m(cls)\u001b[0m\n\u001b[0;32m     11\u001b[0m     \u001b[1;32mdef\u001b[0m \u001b[0mex_cls_method\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mcls\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     12\u001b[0m         \u001b[0mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"I'm a class method\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 13\u001b[1;33m         \u001b[0mcls\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mexample_function\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mcls\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;32m<ipython-input-15-9160b7733cf5>\u001b[0m in \u001b[0;36mexample_function\u001b[1;34m(self)\u001b[0m\n\u001b[0;32m      6\u001b[0m     \u001b[1;32mdef\u001b[0m \u001b[0mexample_function\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      7\u001b[0m         \u001b[0mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m'I\\'m an instance method!'\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 8\u001b[1;33m         \u001b[0mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m'My name is '\u001b[0m \u001b[1;33m+\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mname\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m      9\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     10\u001b[0m     \u001b[1;33m@\u001b[0m\u001b[0mclassmethod\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;31mAttributeError\u001b[0m: type object 'MethodExample' has no attribute 'name'"
     ]
    }
   ],
   "source": [
    "ex = MethodExample()\n",
    "ex.ex_cls_method()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Static Methods\n",
    "\n",
    "These methods sorta just exist and do their thing. The don't know anything about class-specific data and the class they are contained in doesn't need to be instanced to call upon the method."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [],
   "source": [
    "class StaticExample:\n",
    "    def __init__(self):\n",
    "        print (\"I LIVE!\")\n",
    "    \n",
    "    @staticmethod\n",
    "    def static_method():\n",
    "        print(\"Am I alive?\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Am I alive?\n"
     ]
    }
   ],
   "source": [
    "StaticExample.static_method()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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