Python 1 - Getting Started.ipynb

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   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hello World\n"
     ]
    }
   ],
   "source": [
    "print ('Hello World')"
   ]
  },
  {
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   "source": [
    "#### Features of Python\n",
    "* Interpreted Programming Language. Other examples are PHP, Perl, Shell Script etc\n",
    "* Vs Compiled Programming Language. Examples are c, c+\n",
    "* Dynamically Typed Programming language\n",
    "* High level Programming Language - Works well on both linux & windows except some platform specific libraries"
   ]
  },
  {
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   "execution_count": 6,
   "metadata": {
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   "source": [
    "#No need to mention type information\n",
    "#Type of variable is derived from the value assigned to it\n",
    "a = 1\n",
    "a = 'Hello'"
   ]
  },
  {
   "cell_type": "code",
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   "metadata": {},
   "outputs": [
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     "data": {
      "text/plain": [
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      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "type(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "#Object Model of Python\n",
    "#a = 1 -> 'a' points to a piece of memory which holds value 1, That piece of memory also holds type information\n",
    "#a = 'hello' -> a is re-referenced to a piece of memory which holds 'Hello'"
   ]
  },
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   "execution_count": 10,
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       "1907192788056"
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     "execution_count": 10,
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   "source": [
    "id(a)\n",
    "#tells you the address of a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": true
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   "outputs": [],
   "source": [
    "a = 10\n",
    "b = 10"
   ]
  },
  {
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   "execution_count": 12,
   "metadata": {},
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     "data": {
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       "1369759792"
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     "execution_count": 12,
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   "source": [
    "id(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
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     "data": {
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       "1369759792"
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     "execution_count": 13,
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   ],
   "source": [
    "id(b)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Optimization By Python\n",
    "* For numbers below 255, it tries to reuse the memory\n",
    "* More chances of re-using smaller numbers compared to larger ones\n",
    "* If done for all numbers, system performance goes for toss\n",
    "* Same behavious is depicted for smaller length strings"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "a = 5.0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "float"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "type(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "b = 8723981724981723981732981732981732981723891723981723987129837189237"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "int"
      ]
     },
     "execution_count": 18,
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     "output_type": "execute_result"
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   ],
   "source": [
    "type(b)"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Memory \n",
    "* Automatic memory allocation & deletion in Python\n",
    "* Garbage collection get activated & reclaims all unused pieces of memory"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Operators"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "14"
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     "execution_count": 19,
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   ],
   "source": [
    "289182 % 22"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
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     "data": {
      "text/plain": [
       "25"
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     "execution_count": 20,
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   ],
   "source": [
    "5 ** 2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Strings\n",
    "* Immutable - The content cannot be changed but, the reference can be"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "a = 'hello world'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'hello worldhello world'"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\n",
    "a + a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'e'"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a[1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'hello world'"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [],
   "source": [
    "#a[1] = 'h'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "a = 'Good great God'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'d'"
      ]
     },
     "execution_count": 29,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a[-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Goo'"
      ]
     },
     "execution_count": 32,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#Slicing\n",
    "a[:3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'d gre'"
      ]
     },
     "execution_count": 31,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a[3:8]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Good great God'"
      ]
     },
     "execution_count": 33,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'doG taerg dooG'"
      ]
     },
     "execution_count": 34,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a[::-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {
    "collapsed": true
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   "outputs": [],
   "source": [
    "##None of the operation will ever change the contents of a but returns the changed value"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Good great God'"
      ]
     },
     "execution_count": 36,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Good great God'"
      ]
     },
     "execution_count": 37,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'God Good great '"
      ]
     },
     "execution_count": 40,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a[-3:] + ' ' + a[:-3]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Help manual"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 44,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on built-in function count:\n",
      "\n",
      "count(...) method of builtins.str instance\n",
      "    S.count(sub[, start[, end]]) -> int\n",
      "    \n",
      "    Return the number of non-overlapping occurrences of substring sub in\n",
      "    string S[start:end].  Optional arguments start and end are\n",
      "    interpreted as in slice notation.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(a.count)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Understanding String library"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "s = 'hello world, here i come again to trouble you all'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on built-in function capitalize:\n",
      "\n",
      "capitalize(...) method of builtins.str instance\n",
      "    S.capitalize() -> str\n",
      "    \n",
      "    Return a capitalized version of S, i.e. make the first character\n",
      "    have upper case and the rest lower case.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(s.capitalize)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 47,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Hello world, here i come again to trouble you all'"
      ]
     },
     "execution_count": 47,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.capitalize()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "metadata": {},
   "outputs": [],
   "source": [
    "s = s.capitalize()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Hello world, here i come again to trouble you all'"
      ]
     },
     "execution_count": 50,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "3"
      ]
     },
     "execution_count": 51,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.count('a')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 52,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "9"
      ]
     },
     "execution_count": 52,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.count(' ')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2"
      ]
     },
     "execution_count": 53,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.count('ll')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 55,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 55,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.endswith('ally')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 56,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 56,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "True #Valid\n",
    "False #Invalid"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 63,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "46"
      ]
     },
     "execution_count": 63,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.find('al',23)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 60,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on built-in function find:\n",
      "\n",
      "find(...) method of builtins.str instance\n",
      "    S.find(sub[, start[, end]]) -> int\n",
      "    \n",
      "    Return the lowest index in S where substring sub is found,\n",
      "    such that sub is contained within S[start:end].  Optional\n",
      "    arguments start and end are interpreted as in slice notation.\n",
      "    \n",
      "    Return -1 on failure.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(s.find)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "s."
   ]
  }
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