classes and objects(Part 1).ipynb

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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# OOP concepts:Classes and objects(Part 1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Robot:\n",
    "    def introduce_self(self): # self as a parameter as it is defined in a class \n",
    "        print(\"My name is \" + self.name) #self is similar to \"this\" keyword in java"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "creating objects and assigning attributes to each object manually"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "r1=Robot()\n",
    "r1.name=\"Tom\"\n",
    "r1.color=\"red\"\n",
    "r1.weight=30"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "My name is Tom\n"
     ]
    }
   ],
   "source": [
    "r1.introduce_self()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "# create another object\n",
    "\n",
    "r2=Robot()\n",
    "r2.name=\"jerry\"\n",
    "r2.color=\"Green\"\n",
    "r2.weight=20"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "My name is Tom\n",
      "My name is jerry\n"
     ]
    }
   ],
   "source": [
    "r1.introduce_self()\n",
    "r2.introduce_self()"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "attribute should be named properly if it is intended to access later"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "r3=Robot()\n",
    "r3.nameee=\"jerry\"\n",
    "r3.color=\"Green\"\n",
    "r3.weight=25"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "ename": "AttributeError",
     "evalue": "'Robot' object 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-8-0a6252a5610b>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mr3\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mintroduce_self\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-1-fbd34db30ae6>\u001b[0m in \u001b[0;36mintroduce_self\u001b[1;34m(self)\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[1;32mclass\u001b[0m \u001b[0mRobot\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      2\u001b[0m     \u001b[1;32mdef\u001b[0m \u001b[0mintroduce_self\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m \u001b[1;31m# self as a parameter as it is defined in a class\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 3\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;31m#self is similar to \"this\" keyword in java\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mAttributeError\u001b[0m: 'Robot' object has no attribute 'name'"
     ]
    }
   ],
   "source": [
    "r3.introduce_self()"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "introduce_self print self.name that means it prints attribute \"name\" 's value which we spelled mistakenly \"nameee\""
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    " so it gives attribute error as the print self.name didn't find any such \"name\" attribute"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "To overcome this issue, we use constructors to initialize the attributes"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [],
   "source": [
    "class RobotX:\n",
    "    #constructor below\n",
    "    def __init__(self,given_name,given_color,given_weight):\n",
    "        self.name=given_name\n",
    "        self.color=given_color\n",
    "        self.weight=given_weight\n",
    "    \n",
    "    # not that self is added as the 1st parameter to all the defined functions including constructors\n",
    "    #attributes \"given_name\" \"given_color\",\"given_weight\" can be kept anything user-defined to use it throughout the function\n",
    "    def introduce_self(self): \n",
    "        print(\"My name is \" + self.name + \"\\nMy color is \" + self.color)\n",
    "        print(\"My weight is \",self.weight)\n",
    "        "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [],
   "source": [
    "ro = RobotX(\"Tom\",\"brown\",10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "My name is Tom\n",
      "My color is brown\n",
      "My weight is  10\n"
     ]
    }
   ],
   "source": [
    "ro.introduce_self()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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