{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#Accessing Values in Strings\n",
    "\n",
    "Python does not support a character type; these are treated as strings of length one, thus also considered a substring.\n",
    "\n",
    "To access substrings, use the square brackets for slicing along with the index or indices to obtain your substring. For example −"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "('var1[0]: ', 'H')\n",
      "('var2[1:5]: ', 'ytho')\n"
     ]
    }
   ],
   "source": [
    "var1 = 'Hello World!'\n",
    "var2 = \"Python Programming\"\n",
    "\n",
    "print(\"var1[0]: \", var1[0])\n",
    "print(\"var2[1:5]: \", var2[1:5])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#Updating Strings\n",
    "\n",
    "You can \"update\" an existing string by (re)assigning a variable to another string. The new value can be related to its previous value or to a completely different string altogether. For example −"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Updated String :- Hello Python\n"
     ]
    }
   ],
   "source": [
    "var1 = 'Hello World! '\n",
    "\n",
    "print(\"Updated String :- \" + var1[:6] + 'Python')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#String Special Operators"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Hello World! Hello World! Hello World! Hello World! '"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "var1 * 4"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'Python' in var1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'World' in var1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'world' not in var1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#String Formatting Operator"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "My name is Zara and weight is 21 kg!\n"
     ]
    }
   ],
   "source": [
    "print(\"My name is %s and weight is %d kg!\" % ('Zara', 21)) "
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "Format Symbol\tConversion\n",
    "%c \tcharacter\n",
    "%s \tstring conversion via str() prior to formatting\n",
    "%i \tsigned decimal integer\n",
    "%d \tsigned decimal integer\n",
    "%u \tunsigned decimal integer\n",
    "%o \toctal integer\n",
    "%x \thexadecimal integer (lowercase letters)\n",
    "%X \thexadecimal integer (UPPERcase letters)\n",
    "%e \texponential notation (with lowercase 'e')\n",
    "%E \texponential notation (with UPPERcase 'E')\n",
    "%f \tfloating point real number\n",
    "%g \tthe shorter of %f and %e\n",
    "%G \tthe shorter of %f and %E"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#Triple Quotes\n",
    "\n",
    "Python's triple quotes comes to the rescue by allowing strings to span multiple lines, including verbatim NEWLINEs, TABs, and any other special characters."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "this is a long string that is made up of\n",
      "several lines and non-printable characters such as\n",
      "TAB ( \t ) and they will show up that way when displayed.\n",
      "NEWLINEs within the string, whether explicitly given like\n",
      "this within the brackets [ \n",
      " ], or just a NEWLINE within\n",
      "the variable assignment will also show up.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "para_str = \"\"\"this is a long string that is made up of\n",
    "several lines and non-printable characters such as\n",
    "TAB ( \\t ) and they will show up that way when displayed.\n",
    "NEWLINEs within the string, whether explicitly given like\n",
    "this within the brackets [ \\n ], or just a NEWLINE within\n",
    "the variable assignment will also show up.\n",
    "\"\"\"\n",
    "print(para_str);\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#Built-in String Methods"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "3\n",
      "2\n"
     ]
    }
   ],
   "source": [
    "value = \"finnegans wake\"\n",
    "\n",
    "# Count this substring.\n",
    "print(value.count(\"n\"))\n",
    "\n",
    "# Count substring in indexes 0 to 6.\n",
    "print(value.count(\"n\", 0, 6))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "True\n",
      "True\n",
      "False\n"
     ]
    }
   ],
   "source": [
    "s = \"voorheesville\"\n",
    "\n",
    "print(s.startswith(\"voo\"))\n",
    "    \n",
    "\n",
    "print(s.endswith(\"ville\"))\n",
    "\n",
    "\n",
    "print(s.startswith(\"stuy\"))\n",
    "    # Not reached.\n",
    "   "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Paris.....\n",
      "     Paris\n"
     ]
    }
   ],
   "source": [
    "s = \"Paris\"\n",
    "\n",
    "# Justify to left, add periods.\n",
    "print(s.ljust(10, \".\"))\n",
    "\n",
    "# Justify to right.\n",
    "print(s.rjust(10))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "aayz\n",
      "xabc\n"
     ]
    }
   ],
   "source": [
    "value = \"aabc\"\n",
    "\n",
    "# Replace a substring with another.\n",
    "result = value.replace(\"bc\", \"yz\")\n",
    "print(result)\n",
    "\n",
    "# Replace the first occurrence with a substring.\n",
    "result = value.replace(\"a\", \"x\", 1)\n",
    "print(result)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1,000\n",
      ":::::::cat\n"
     ]
    }
   ],
   "source": [
    "# Format this number with a comma.\n",
    "result = format(1000, \",\")\n",
    "print(result)\n",
    "\n",
    "# Align to the right of 10 chars, filling with \":\" and as a string.\n",
    "result = format(\"cat\", \":>10s\")\n",
    "print(result)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Hello', 'world!']"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "astring = \"Hello world!\"\n",
    "afewwords = astring.split(\" \")\n",
    "afewwords"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#Exercise\n",
    "Try to fix the code to print out the correct information by changing the string."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Length of s = 38\n",
      "The first occurrence of the letter a = 13\n",
      "a occurs 1 times\n"
     ]
    }
   ],
   "source": [
    "s = \"Hey there! what should this string be?\"\n",
    "\n",
    "# Length should be 20\n",
    "print \"Length of s = %d\" % len(s)\n",
    "\n",
    "# First occurrence of \"a\" should be at index 8\n",
    "print \"The first occurrence of the letter a = %d\" % s.index(\"a\")\n",
    "\n",
    "# Number of a's should be 2\n",
    "print \"a occurs %d times\" % s.count(\"a\")\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 2",
   "language": "python",
   "name": "python2"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 2
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython2",
   "version": "2.7.6"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}