001_python syntax.ipynb

{
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# python syntax\n",
    "\n",
    "===>> comments\n",
    "\n",
    "===>> statement"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello\n",
      "hai\n",
      "bye\n"
     ]
    }
   ],
   "source": [
    "# single line comment\n",
    "'''\n",
    "===>> this is \n",
    "mutliple line \n",
    "comment\n",
    "'''\n",
    "print \"hello\" # this is statement\n",
    "print \"hai\"\n",
    "print \"bye\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# keywords \n",
    "\n",
    "===>> predefined word/ reservsed word\n",
    "\n",
    "===>> python2 ==>> 31 /   python3 ===> 35\n",
    "\n",
    "===>> keyword is a python module ===>> we have all keywords\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "31\n",
      "['and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'exec', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'not', 'or', 'pass', 'print', 'raise', 'return', 'try', 'while', 'with', 'yield']\n"
     ]
    }
   ],
   "source": [
    "import keyword\n",
    "print len(keyword.kwlist)\n",
    "print keyword.kwlist"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# identifiers \n",
    "\n",
    "===>>  which are usr defined words \n",
    "\n",
    "===>>  To give the name entities for function / variables/ class\n",
    "\n",
    "# rules\n",
    "\n",
    "===>> We can use alphabets   -->>   a-z  / A-z\n",
    "\n",
    "===>>  We can use digits    ---->>   0-9\n",
    "\n",
    "===>>  we can use underscore    _\n",
    "\n",
    "===>>  don't use keywords \n",
    "\n",
    "===>>  don't use special characters\n",
    "\n",
    "===>>  don't start with digit"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "True\n",
      "1750646504\n",
      "<type 'bool'>\n"
     ]
    }
   ],
   "source": [
    "# variable \n",
    "'''\n",
    "===>> It is an indentifier  which is used for to store the data with in the memory loc\n",
    "\n",
    "===>> In python we don't to be declare the variable\n",
    "\n",
    "===>> we can directly assign the data to the variable/ identifier\n",
    "'''\n",
    "var = True\n",
    "print var\n",
    "print id(var)\n",
    "print type(var)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "46430560\n",
      "46430560\n",
      "46433872\n",
      "46430560\n"
     ]
    }
   ],
   "source": [
    "a =12\n",
    "b =12\n",
    "print id(a)\n",
    "print id(b)\n",
    "a =123\n",
    "print(id(a))\n",
    "print(id(b))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "123\n"
     ]
    }
   ],
   "source": [
    "varJJKFFJ12_ =123\n",
    "print varJJKFFJ12_ "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "invalid syntax (<ipython-input-21-1304142e8cc5>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-21-1304142e8cc5>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    4var =123\u001b[0m\n\u001b[1;37m       ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m invalid syntax\n"
     ]
    }
   ],
   "source": [
    "4var =123"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "invalid syntax (<ipython-input-22-b5802d9d3126>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-22-b5802d9d3126>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    while  =124\u001b[0m\n\u001b[1;37m           ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m invalid syntax\n"
     ]
    }
   ],
   "source": [
    "while  =124"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "invalid syntax (<ipython-input-23-d2d88bca40f1>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-23-d2d88bca40f1>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    va@12 =123\u001b[0m\n\u001b[1;37m      ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m invalid syntax\n"
     ]
    }
   ],
   "source": [
    "va@12 =123"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "123\n"
     ]
    }
   ],
   "source": [
    "_var =123\n",
    "print _var"
   ]
  }
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