Merge pull request #709 from Varshni11/basics-python-ipynb

Create jupyter notebooks for python basics lecture files

Basics of the Python/Basic of Python/2.TUPLES_LECTURE/DICTIONARIES.ipynb

@@ -0,0 +1,295 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h1 style=\"color:blue\">DICTIONARIES</h1>\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<ul type=\"disc\">\n",
+    "<li>Consists of keys and key values separated by a colon</li>\n",
+    "<li> Dictionaries, also called dict can contain,\n",
+    "<ul type=\"square\">\n",
+    "<li>Strings and numbers</li>\n",
+    "<li>Tuples</li>\n",
+    "<li>lists</li>\n",
+    "<li>sets</li>\n",
+    "<li>dataframes</li>\n",
+    "<li>series</li>\n",
+    "<li>nested dictionaries</li>\n",
+    "</ul>\n",
+    "</li>\n",
+    "</ul>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "dict"
+      ]
+     },
+     "execution_count": 1,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "d1={}\n",
+    "type(d1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h2>Adding elements into dictionary</h2>\n",
+    "<p> Elements can be added to dictionary as a key, value pairs in the following way:</p>\n",
+    "<code> dictionary[key]=value </code>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "{'A': 10, 'B': 20, 'C': 30}\n"
+     ]
+    }
+   ],
+   "source": [
+    "d1['A']=10\n",
+    "d1['B']=20\n",
+    "d1['C']=30\n",
+    "print(d1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h2>Changing values in dictionary</h2>\n",
+    "<p>Dictionaries are mutable, meaning the values referenced by dictionary keys can be changed. This is illustrated in the following example...</p>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Dictionaries before changing value of 'C' {'A': 10, 'B': 20, 'C': 1000}\n",
+      "Dictionaries after changing value of 'C' {'A': 10, 'B': 20, 'C': 1000}\n"
+     ]
+    }
+   ],
+   "source": [
+    "print(\"Dictionaries before changing value of 'C'\",d1)\n",
+    "d1[\"C\"] = 1000\n",
+    "print(\"Dictionaries after changing value of 'C'\",d1)\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<hr><br>We can also update a dictionary with elements of another dictionary as follows..."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'robot': 40, 'car': 50, 'A': 10, 'B': 20, 'C': 1000}"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "toys = {\"robot\": 40, \"car\": 50}\n",
+    "toys.update(d1)\n",
+    "toys\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h2> Accessing the keys and values seperately</h2>\n",
+    "We can get the keys and values seperately using keys() and values() methods respectively. They can converted to a list by wrapping it inside the list() method"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "dict_values([40, 50, 20, 1000])"
+      ]
+     },
+     "execution_count": 13,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "toys.values()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "dict_keys(['robot', 'car', 'A', 'B', 'C'])"
+      ]
+     },
+     "execution_count": 9,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "list(toys.keys())"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h2>Deleting an element from Dictionary</h2>\n",
+    "<p>To remove an key-value pair, we use pop(key)</p>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'robot': 40, 'car': 50, 'B': 20, 'C': 1000}"
+      ]
+     },
+     "execution_count": 10,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "\n",
+    "toys.pop(\"A\")\n",
+    "toys\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "More examples..."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'k1': [0, 1, 2, 3],\n",
+       " 'k2': (4, 5, 6, 7),\n",
+       " 'k3': (1, 2, 3, {'k4': [1, 2, 3, 'found you!', 4, 5]})}"
+      ]
+     },
+     "execution_count": 11,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "maze = {\"k1\": list(range(4)), \"k2\": tuple(range(4,8)),\n",
+    "\"k3\": (1,2, 3, {\"k4\": [1,2,3, \"found you!\", 4, 5]})}\n",
+    "maze\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'found you!'"
+      ]
+     },
+     "execution_count": 12,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "maze[\"k3\"][3][\"k4\"][3]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "vars",
+   "language": "python",
+   "name": "vars"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.5"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}