009_classes.ipynb

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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 009_classes\n",
    "\n",
    "[Source](https://github.com/iArunava/Python-TheNoTheoryGuide/)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
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   "source": [
    "# Simple class\n",
    "class Programmer():\n",
    "    \"\"\"This is called a docstring. This class is to create a Programmer. \n",
    "       Functions inside a class is called a method.\n",
    "       Methods are automatically passed the 'self' argument. \n",
    "       Any variable prefixed with 'self.' is available to the class.\n",
    "       We will also be able to access this self prefixed variables from any instance of the class.\"\"\"\n",
    "    \n",
    "    def __init__(self, name, age, *known_languages):\n",
    "        \"\"\"__init__ is a special method that Python automatically calls \n",
    "           when a new instance of the class is created. \"\"\"\n",
    "        self.name = name\n",
    "        self.age = age\n",
    "        self.languages = set(known_languages)\n",
    "        \n",
    "        # Default value for a class variable\n",
    "        self.concepts_revised = 0\n",
    "        \n",
    "    def add_new_language(self, lang):\n",
    "        self.languages.add(lang)\n",
    "        print (str(self.name) + \" knows a new language : \" + str(lang) + \" !!\")\n",
    "        \n",
    "    def revise_concept(self, concept):\n",
    "        self.concepts_revised += 1\n",
    "        print (str(self.name) + \" just revised \" + str(concept) + \" !!\")\n",
    "    \n",
    "    def languages_known(self):\n",
    "        return list(self.languages)\n",
    "        \n",
    "    def cv(self):\n",
    "        print (\"Name   : \" + str(self.name))\n",
    "        print (\"Age    : \" + str(self.age))\n",
    "        print (\"Skills : \" + str(self.languages))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Creating an instance of the class\n",
    "# This calls the __init__() method\n",
    "a_programmer = Programmer(\"Jennifer\", 21, \"Python\", \"R\", \"Julia\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Accessing the attributes\n",
    "print (a_programmer.name.title())\n",
    "print (a_programmer.age)\n",
    "print (a_programmer.languages)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Calling Methods\n",
    "a_programmer.add_new_language(\"Ruby\")\n",
    "print (a_programmer.languages)\n",
    "\n",
    "print (\"\\nCV for \" + str(a_programmer.name.title()) + \"\\n=================\")\n",
    "a_programmer.cv()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Creating multiple instances\n",
    "b_programmer = Programmer (\"Scarlett\", 21, \"Python\", \"Julia\", \"SPLUS\", \"Ruby\")\n",
    "c_programmer = Programmer (\"Ariel\", 20, \"C++\", \"Java\", \"Python\")\n",
    "\n",
    "print (\"\\nCV for \" + str(b_programmer.name.title()) + \"\\n=================\")\n",
    "b_programmer.cv()\n",
    "\n",
    "print (\"\\nCV for \" + str(c_programmer.name.title()) + \"\\n=================\")\n",
    "c_programmer.cv()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Directly modifying Attribute's value\n",
    "print (\"Concepts Revised by \" + str(b_programmer.name.title()) + \" : \" + str(b_programmer.concepts_revised))\n",
    "b_programmer.concepts_revised += 10\n",
    "print (\"Concepts Revised by \" + str(b_programmer.name.title()) + \" : \" + str(b_programmer.concepts_revised))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Modifying Attribute's value through a method\n",
    "print (\"\\nConcepts Revised by \" + str(c_programmer.name.title()) + \" : \" + str(c_programmer.concepts_revised))\n",
    "c_programmer.revise_concept(\"Python Lists\")\n",
    "c_programmer.revise_concept(\"Python Tuples\")\n",
    "c_programmer.revise_concept(\"Python Dictionaries\")\n",
    "print (\"Concepts Revised by \" + str(c_programmer.name.title()) + \" : \" + str(c_programmer.concepts_revised))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Inheritance\n",
    "'''\n",
    "Programmer => Parent Class\n",
    "Developer  => Child Class\n",
    "\n",
    "Child class inherits from the base class.\n",
    "The classes share a IS A relationship.\n",
    "So, in this case, Developer IS A Programmer.\n",
    "It has available all methods and variables from the parent class.\n",
    "And can define methods and variables of its own.\n",
    "'''\n",
    "class Developer(Programmer):\n",
    "    def __init__(self, name, age, expertise, yoe, *known_languages):\n",
    "        \n",
    "        # Call the parent class to initialize and give the child class an instance of the parent\n",
    "        super().__init__(name, age, known_languages)\n",
    "        self.expertise = expertise\n",
    "        self.years_of_experience = yoe\n",
    "        \n",
    "    def specializes_in(self):\n",
    "        return self.expertise\n",
    "    \n",
    "    def cv(self):\n",
    "        \"\"\"\n",
    "        This method overrides the cv() method in the parent class.\n",
    "        Any method in child class with same name as a method inherited from parent class\n",
    "        overrides the parent class method.\n",
    "        \"\"\"\n",
    "        print (\"Name                : \" + str(self.name))\n",
    "        print (\"Age                 : \" + str(self.age))\n",
    "        print (\"Skills              : \" + str(self.languages))\n",
    "        print (\"Expertise           : \" + str(self.expertise))\n",
    "        print (\"Years of Experience : \" + str(self.years_of_experience))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Creating an instance of the child class\n",
    "a_developer = Developer (\"Jennifer\", 21, \"Android\", 2, \"Java\", \"Kotlin\", \"Python\", \"R\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Call to methods and variables from the child as well as parent class\n",
    "print (str(a_developer.name) + \" specializes in \" + str(a_developer.specializes_in()) + \".\")\n",
    "print (str(a_developer.name) + \" can code in \" + str(a_developer.languages_known()) + \".\")\n",
    "print (str(a_developer.name) + \" has \" + str(a_developer.years_of_experience) + \" years of experience.\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Calling the overriden method in the child class\n",
    "a_developer.cv()"
   ]
  }
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