{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Using Strings in Python 3\n",
    "[Python String docs](https://docs.python.org/3/library/string.html)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Creating Strings\n",
    "Enclose a string in single or double quotes, or in triple single quotes.  \n",
    "And you can embed single quotes within double quotes, or double quotes within single quotes. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Tony Stark is Ironman.\n",
      "Her book is called \"The Magician\".\n",
      "Captain Rogers kicks butt.\n"
     ]
    }
   ],
   "source": [
    "s = 'Tony Stark is'\n",
    "t = \"Ironman.\"\n",
    "print(s, t)\n",
    "u = 'Her book is called \"The Magician\".'\n",
    "print(u)\n",
    "v = '''Captain Rogers kicks butt.'''\n",
    "print(v)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Type, Len, Split, Join\n",
    "Get the number of characters in a string using len.  \n",
    "To get the number of words you have to split the string into a list. Split uses a space as its default, or you can split on any substring you like.  \n",
    "To reverse a split, use join(str)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "<class 'str'>\n",
      "13\n"
     ]
    }
   ],
   "source": [
    "print(type(s))\n",
    "print(len(s))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['Tony', 'Stark', 'is']\n",
      "3\n",
      "['Her book is c', 'lled \"The M', 'gici', 'n\".']\n",
      "['you', 'are', 'so', 'pretty']\n",
      "Just do it.\n"
     ]
    }
   ],
   "source": [
    "print(s.split())\n",
    "print(len(s.split()))\n",
    "print(u.split('a'))\n",
    "print('you,are,so,pretty'.split(','))\n",
    "print(' '.join(['Just', 'do', 'it.']))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Check if a substring is contained in a string\n",
    "Use *in* or *not in*.  \n",
    "Startswith and Endswith are also useful boolean checks."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "False\n",
      "False\n",
      "True\n",
      "True\n",
      "True\n"
     ]
    }
   ],
   "source": [
    "print('dog' in s)\n",
    "print('k' in t)\n",
    "print('k' not in t)\n",
    "print(s.startswith('Tony'))\n",
    "print(s.endswith('is'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Replace all substrings\n",
    "Second example iterates through a dictionary and replaces all instances of text numbers with numerals."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Captain America kicks butt.\n"
     ]
    }
   ],
   "source": [
    "v = v.replace('Rogers', 'America')\n",
    "print(v)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Anton has 3 cars. Javier has 4.\n"
     ]
    }
   ],
   "source": [
    "z = 'Anton has three cars. Javier has four.'\n",
    "numbers = {'one':'1', 'two':'2', 'three':'3', 'four':'4', 'five':'5'}\n",
    "for k,v in numbers.items():\n",
    "    z = z.replace(k,v)\n",
    "print(z)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Change case"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "tony stark is\n",
      "IRONMAN.\n",
      "Her Book Is Called \"The Magician\".\n",
      "Hulk rules!\n"
     ]
    }
   ],
   "source": [
    "print(s.lower())\n",
    "print(t.upper())\n",
    "print(u.title())\n",
    "print('hulk rules!'.capitalize())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "True\n",
      "False\n",
      "True\n",
      "True\n"
     ]
    }
   ],
   "source": [
    "print('david'.islower())\n",
    "print('hulk'.isupper())\n",
    "print('Hulk'.istitle())\n",
    "print('covid19'.isalnum())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "True\n",
      "False\n",
      "True\n",
      "False\n"
     ]
    }
   ],
   "source": [
    "print('Thor'.isalpha())\n",
    "print('3.14'.isnumeric())\n",
    "print('314'.isdigit())\n",
    "print('3.14'.isdecimal())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0123456789\n",
      "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~\n",
      "abcdefghijklmnopqrstuvwxyz\n",
      "ABCDEFGHIJKLMNOPQRSTUVWXYZ\n"
     ]
    }
   ],
   "source": [
    "import string\n",
    "print(string.digits)\n",
    "print(string.punctuation)\n",
    "print(string.ascii_lowercase)\n",
    "print(string.ascii_uppercase)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Strip leading or trailing characters\n",
    "This is often used to strip blank spaces or newlines, but can be used for much more."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Natasha is a spy.\n",
      "Natasha is a spy \n",
      "\n",
      "\n",
      "  Natasha is a spy\n",
      "Natasha is a spy. She has red hair.\n",
      "She has red \n"
     ]
    }
   ],
   "source": [
    "w = '\\n  Natasha is a spy \\n'\n",
    "x = '\\nShe has red hair\\n'\n",
    "\n",
    "print(w.strip() + '.')\n",
    "print(w.lstrip())\n",
    "print(w.rstrip())\n",
    "print(w.strip() + '. ' + x.strip() + '.')\n",
    "print(x.strip().rstrip('arih'))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "What do you want\n"
     ]
    }
   ],
   "source": [
    "y = 'What do you want?!!&?'\n",
    "print(y.rstrip(string.punctuation))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Find, and Count substrings\n",
    "Search from the left with find, or from the right with rfind.  \n",
    "The return value is the start index of the first match of the substring."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "2\n",
      "5\n",
      "What do you want?!!&?\n"
     ]
    }
   ],
   "source": [
    "print(y.find('a'))\n",
    "print(y.rfind('do'))\n",
    "print(y)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Natasha is a spy\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "print(w.strip())\n",
    "print(w.count('a'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Strings are immutable\n",
    "Any change to a string results in a new string being written to a new block of memory. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "4565794160\n",
      "4565793776\n"
     ]
    }
   ],
   "source": [
    "m = 'Black widow'\n",
    "print(id(m))\n",
    "m = m + 's'\n",
    "print(id(m))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Tony Stark is Ironman.\n",
      "Tony Stark is Ironman.\n"
     ]
    }
   ],
   "source": [
    "print(s, t)\n",
    "z = s + ' ' + t\n",
    "print(z)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Slicing Substrings\n",
    "string[from:to+1:step]\n",
    "Only 1 parameter: it is used as an index.  \n",
    "From defaults to beginning.  \n",
    "To defaults to end.  \n",
    "Step defaults to 1."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\n",
      "567\n"
     ]
    }
   ],
   "source": [
    "z = '0123456789'\n",
    "print(z[1])\n",
    "print(z[5:8])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "012\n",
      "789\n",
      "89\n",
      "24\n"
     ]
    }
   ],
   "source": [
    "print(z[:3])\n",
    "print(z[7:])\n",
    "print(z[-2:])\n",
    "print(z[2:5:2])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.7.0"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}