doc/Langauge/10 - Inbuilt Data Structures 5 - Strings.ipynb

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   "source": [
    "# Strings\n",
    "Strings play a major role in a programming language. Apart from providing nicer user interactions, they can also serve as communication tool within the parts of the program. Python provides a rich set of tools for Pattern matching using [RegEx](http://regexr.com/)s, String formatting based on locate and Various encryption methods. We have seen basic String Formatting in [previous chapter](./02-Formatting Output.ipynb). In this chapter let's study about some basic functions that operates on strings.\n",
    "\n",
    "## Creating Strings\n",
    "\n",
    "- Creating Empty String\n",
    "```python\n",
    "    s = str()\n",
    "```\n",
    "    or\n",
    "\n",
    "```python\n",
    "    s = '' # quotes can be any of '' or \"\"\n",
    "```\n",
    "- Creating String with Initial Value\n",
    "```python\n",
    "    s = \"Some text goes here\"\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Accessing the elements of Strings\n",
    "String elements can be accessed using integer indices. A slice can also be specified for accessing a required part of the string"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua'"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s = \"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua\"\n",
    "s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'m'"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s[10]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'t amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua'"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s[20:] # start from 10 to end of string"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Lorem ipsum dolor si'"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s[:20] # start from 0 to index 19"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'mdlrstae,c'"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s[10:30:2] # start from 10, end at 29 with steps of 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'nc,eatsrld'"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s[30:10:-2] # in reverse order"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Operators on Strings"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'Lorem' in s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Some Random text : Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua'"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'Some Random text : ' + s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Lorem ipsum"
     ]
    }
   ],
   "source": [
    "for i,c in enumerate(s): # string is iterable\n",
    "    if i == 11:\n",
    "        break \n",
    "    else:\n",
    "        print(c,end='') "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Operations on Strings\n",
    "\n",
    "If `s` is a string,\n",
    "\n",
    "- `s.format(elements)` formats `s` and returns it\n",
    "- `s.join(elements)` returns a string in which the `elements` have been joined by `s` separator.\n",
    "- `s.capitalize()` Return a copy of the string with its first character capitalized and the rest lowercased.\n",
    "- `s.count(sub[, start[, end]])` Return the number of non-overlapping occurrences of substring `sub` in the range `[start, end]`. Optional arguments `start` and `end` are interpreted as in slice notation.\n",
    "- `s.find(sub[, start[, end]])` Return the lowest index in the string where substring `sub` is found within the slice `s[start:end]`. Optional arguments `start` and `end` are interpreted as in slice notation. Return `-1` if `sub` is not found.\n",
    "- `s.isalpha()` Return `True` if all characters in the string are alphabetic and there is at least one character, `False` otherwise. \n",
    "- `s.split(sep=None, maxsplit=-1)` Return a list of the words in the string, using `sep` as the delimiter string. If `maxsplit` is given, at most `maxsplit` splits are done (thus, the list will have at most `maxsplit+1` elements). If `maxsplit` is not specified or `-1`, then there is no limit on the number of splits (all possible splits are made).\n",
    "- `s.strip([chars])` Return a copy of the string with the leading and trailing characters removed. The `chars` argument is a string specifying the set of characters to be removed. If omitted or None, the chars argument defaults to removing whitespace. The `chars` argument is not a prefix or suffix; rather, all combinations of its values are stripped"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua'"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.count('it')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "19"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.find('it')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Lorem ipsum dolor sit amet',\n",
       " ' consectetur adipiscing elit',\n",
       " ' sed do eiusmod tempor incididunt ut labore et dolore magna aliqua']"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.split(',')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "' sed do eiusmod tempor incididunt ut labore et dolore magna aliqua'"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "part = s.split(',')[2]\n",
    "part"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'sed do eiusmod tempor incididunt ut labore et dolore magna aliqua'"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "part = part.strip()\n",
    "part"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'SED DO EIUSMOD TEMPOR INCIDIDUNT UT LABORE ET DOLORE MAGNA ALIQUA'"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "part = part.upper()\n",
    "part"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'d-e-f-g'"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'-'.join('defg')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "s = 'abcd'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'abcddefg'"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s += 'defg'        # Appending\n",
    "s"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This is just an overview of Python String Functions. There are many more functions which can do various tasks. You will get to know them when you need the functionality."
   ]
  }
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