MLDL Python basics 28.11.20.ipynb

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   "source": [
    "Python Basics"
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   "source": [
    "1+2"
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   "source": [
    "4%2 # finding reminders use modulus i.e, %"
   ]
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   "source": [
    "5//2 ## Quotient only"
   ]
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     "data": {
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       "2.5"
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   "source": [
    "5/2 # "
   ]
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   "source": [
    "# BODMAS Bracket, Off, Division, Multiplication and Subtraction\n",
    "5+3*2"
   ]
  },
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    "(5+3)*2"
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       "int"
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   ],
   "source": [
    "# CHECK DATA TYPE with type()\n",
    "type(2)"
   ]
  },
  {
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       "float"
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   "source": [
    "type(2.5)"
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  {
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   "execution_count": 9,
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     "data": {
      "text/plain": [
       "str"
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   "source": [
    "type('Senthil')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
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     "execution_count": 10,
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   ],
   "source": [
    "#Boolean operation\n",
    "True or False"
   ]
  },
  {
   "cell_type": "code",
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       "bool"
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    "type(True)"
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       "True"
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   "source": [
    "## Assignment qn: what is the different between or |  \n",
    "# | is logical operator\n",
    "# or is bitwise operator\n",
    "True|False"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
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     "data": {
      "text/plain": [
       "True"
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     "execution_count": 18,
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   "source": [
    "a=10\n",
    "b=20\n",
    "a+b>30 | a-b<10 # works for or also"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Strings"
   ]
  },
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   "cell_type": "code",
   "execution_count": null,
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   "outputs": [],
   "source": [
    "# typing ### Strings and droplist Markdown, shift+enter brings the above bold Strings "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Senthil is good boy'"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "# single or double quote in string still gives output. don't name str because variable should\n",
    "#never be named with reserved keywords, then error will come. Then, restart kernel.\n",
    "str1=\"Senthil is good boy\"\n",
    "str1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "A good boy\n",
      "A bad boy\n"
     ]
    }
   ],
   "source": [
    "str1=\"A good boy\"\n",
    "str2=\"A bad boy\"\n",
    "print(str1)\n",
    "print(str2)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'A good boyA bad boy'"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "# merging strings\n",
    "str1+str2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'A good boy A bad boy'"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "str1+\" \"+str2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Enter your name?Senthil Kumar A\n",
      "Senthil Kumar A\n"
     ]
    }
   ],
   "source": [
    "#capturing run time data using input function\n",
    "name=input(\"Enter your name?\")\n",
    "print(name)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "### add 2 numbers as conctaneated. input value given like below is treated as a string. \n",
    "# Fix it by typecasting input to a float or int\n",
    "a=float(input(\"Enter number 1?\"))\n",
    "b=float(input(\"Enter number 2?\"))\n",
    "c=a+b\n",
    "print(\"The Output is \", c)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "What is your first name?Senthil Kumar\n",
      "What is your last name?A\n",
      "My first name is () and last name is ()\n"
     ]
    }
   ],
   "source": [
    "### string formating\n",
    "first_name=input(\"What is your first name?\")\n",
    "last_name=input(\"What is your last name?\")\n",
    "\n",
    "# () empty placeholder\n",
    "# .format() for filling placeholder\n",
    "print(\"My first name is () and last name is ()\".format(first_name,last_name))\n",
    "\n",
    "# print(\"My first name is (firstname) and last name is (lastname)\".format(lastname=last_name, firstname=first_name))"
   ]
  },
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   "cell_type": "code",
   "execution_count": 2,
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    {
     "ename": "NameError",
     "evalue": "name 'last_name' is not defined",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mNameError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-2-d76009102c0c>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[1;31m# () empty placeholder\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;31m# .format() for filling placeholder\u001b[0m\u001b[1;33m\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 first name is (firstname) and last name is (lastname)\"\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mformat\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mlastname\u001b[0m\u001b[1;33m=\u001b[0m\u001b[0mlast_name\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mfirstname\u001b[0m\u001b[1;33m=\u001b[0m\u001b[0mfirst_name\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;31mNameError\u001b[0m: name 'last_name' is not defined"
     ]
    }
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   "source": []
  },
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   "metadata": {},
   "source": [
    "##Variable Dynamic Typing"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "a=10.0\n",
    "type(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "## Strong typing\n",
    "'Krish'+1 # wont work, because concatenation will work only between same types.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "1+int(\"2\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "### conditional statements\n",
    "## if and elif\n",
    "a=int(input(\"Enter the number1?\"))\n",
    "b=int(input(\"Enter the number2?\"))\n",
    "c=a-b\n",
    "print(\"The output is\",c)\n",
    "\n",
    "if c<0:\n",
    "    print(\"The number is negative\")\n",
    "else:\n",
    "    print(\"The number is positive\")\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Enter the number1?80\n",
      "Enter the number2?10\n",
      "The output is 70\n",
      "The difference is huge\n"
     ]
    }
   ],
   "source": [
    "### conditional statements  if, elseif i.e., elif, then else\n",
    "## if and elif\n",
    "a=int(input(\"Enter the number1?\"))\n",
    "b=int(input(\"Enter the number2?\"))\n",
    "c=a-b\n",
    "print(\"The output is\",c)\n",
    "\n",
    "if c<0:\n",
    "    print(\"The number is negative\")\n",
    "elif c>40:\n",
    "    print(\"The difference is huge\")\n",
    "else:\n",
    "    print(\"The number is positive\")\n",
    "\n",
    "##indentation goes wrong, then error will come. any further conditions after if should be housed as elif only, the last one is else."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": []
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Data Structures\n",
    "1. list : collection of homogenous elements like 1,2,3,\"Krish\". lst=[1,2,3,\"Krish\"] Often called with index number. Python index starts with Zero.\n",
    "2. tuple\n",
    "3. string\n",
    "4. Dictionary\n",
    "5. Sets"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Krish'"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "lst=[1,2,3,\"Krish\"]\n",
    "type(lst)\n",
    "lst[3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3, 'Krish', 'iNeuron', 'iNeuron']"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "lst.append(\"iNeuron\")\n",
    "lst"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "3"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "lst[2]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Data Science\n"
     ]
    }
   ],
   "source": [
    "# replace elements in the list\n",
    "lst[2]=\"Data Science\"\n",
    "print(lst[2])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [],
   "source": [
    "lst.append(\"Krish\")\n",
    "lst.append(\"Krish\")\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "lst.count(2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'s'"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#strings doesnot suppport item assignment, you can change only as a full string word. ie., string is immutable. you cannot change the item inside the string.\n",
    "# whereas in list, you can change the items inside. i.e., string is mutable.\n",
    "\n",
    "# Indexing\n",
    "str1=\"Krish\"\n",
    "str1[3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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