04-lists.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 4.Lists\n",
    "Python *lists* can store multiple values within a single variable. A list is created by enclosing a series of comma-separated values with square brackets (`[]`). "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[1, 2, 3, 4, 5, 6, 7]\n"
     ]
    }
   ],
   "source": [
    "one_to_seven = [1, 2, 3, 4, 5, 6, 7]\n",
    "print(one_to_seven)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['first string', 100, 3.142, 'last string']\n"
     ]
    }
   ],
   "source": [
    "# This is a mixed list\n",
    "mixed_list = [\"first string\", 100, 3.142, \"last string\"]\n",
    "print(mixed_list)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['first string', 100, 3.142, 'last string', 100]"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "mixed_list=mixed_list + [100]\n",
    "mixed_list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['Aminah', 'Amir', 'Raj']\n"
     ]
    }
   ],
   "source": [
    "# Place variables into list\n",
    "customer_one = \"Aminah\"\n",
    "customer_two = \"Amir\"\n",
    "customer_three = \"Raj\"\n",
    "all_customers = [customer_one, customer_two, customer_three]\n",
    "print(all_customers)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['one', 'two', 'three', 'four']\n"
     ]
    }
   ],
   "source": [
    "# Combining using + operator\n",
    "list_one = [\"one\", \"two\"]\n",
    "list_two = [\"three\", \"four\"]\n",
    "list_three = list_one + list_two\n",
    "print(list_three)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<font color=\"blue\">Exercise</font>: Define a function called `combine_lists` that takes 4 arguments - `list1`, `list2`,`list3` and `list4` - and returns a list that is the combination of the four lists."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "# YOUR CODE HERE\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "ename": "NameError",
     "evalue": "name 'combine_lists' is not defined",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mNameError\u001b[0m                                 Traceback (most recent call last)",
      "Cell \u001b[0;32mIn[7], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mcombine_lists\u001b[49m(list4\u001b[38;5;241m=\u001b[39m[\u001b[38;5;241m1\u001b[39m,\u001b[38;5;241m2\u001b[39m],list3\u001b[38;5;241m=\u001b[39m[\u001b[38;5;241m3\u001b[39m,\u001b[38;5;241m4\u001b[39m],list2\u001b[38;5;241m=\u001b[39m[\u001b[38;5;241m5\u001b[39m,\u001b[38;5;241m6\u001b[39m],list1\u001b[38;5;241m=\u001b[39m[\u001b[38;5;241m7\u001b[39m,\u001b[38;5;241m8\u001b[39m])\n",
      "\u001b[0;31mNameError\u001b[0m: name 'combine_lists' is not defined"
     ]
    }
   ],
   "source": [
    "combine_lists(list4=[1,2],list3=[3,4],list2=[5,6],list1=[7,8])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "In Python list method `len()` returns the number of elements in the list."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "7"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "len(one_to_seven)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<font color=\"blue\">Try</font>: Use the `len(...)` function to find the length of the list `[1,2,3,4,5]`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Use the `sum(...)` function to add up the elements in a list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "200"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "sum([10,8,1,100,81])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**max()** function returns the largest item in an iterable (list). It can also be used to find the largest item between two or more parameters.\n",
    "\n",
    "**min()** function returns the smallest item in an iterable (list). It can also be used to find the smallest item between two or more parameters"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<span style=\"color:red;font-weight:bold\">Try</span>: Use the `min(...)` and `max(...)` function to find the min of the list `[1,2,3,4,5]`:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<font color=\"blue\">Exercise</font>: Define a function called **average_of_list** that accepts one argument called **inputlist** and returns the average value (arithmetic mean) of the items in the list. \n",
    "\n",
    "For example, if the list **[10,12,23]** is passed as the argument, your function should return **15**. You may use **sum** and **len** functions."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "# YOUR CODE HERE\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "ename": "NameError",
     "evalue": "name 'average_of_list' is not defined",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mNameError\u001b[0m                                 Traceback (most recent call last)",
      "Cell \u001b[0;32mIn[11], line 3\u001b[0m\n\u001b[1;32m      1\u001b[0m x \u001b[38;5;241m=\u001b[39m [\u001b[38;5;241m10\u001b[39m,\u001b[38;5;241m12\u001b[39m,\u001b[38;5;241m23\u001b[39m]\n\u001b[0;32m----> 3\u001b[0m \u001b[38;5;28mprint\u001b[39m(\u001b[43maverage_of_list\u001b[49m(x))\n",
      "\u001b[0;31mNameError\u001b[0m: name 'average_of_list' is not defined"
     ]
    }
   ],
   "source": [
    "x = [10,12,23]\n",
    "\n",
    "print(average_of_list(x))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Accessing List Elements - using slice notation\n",
    "\n",
    "Consider this list of customers:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Fikri Bakri', 'Amir Hossein', 'Lim Pak Hon', 'Kumaran', 'Wong Kim Mun']"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "customers = [\"Fikri Bakri\", \"Amir Hossein\", \"Lim Pak Hon\", \"Kumaran\", \"Wong Kim Mun\"]\n",
    "customers"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Fikri Bakri'"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# The first element\n",
    "customers[0]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Wong Kim Mun'"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# The forth element\n",
    "customers[3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Kumaran'"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Count from the right\n",
    "customers[-2]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Amir Hossein', 'Kumaran', 'Wong Kim Mun']"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Use colon to slice the lists\n",
    "customers[1:4]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Fikri Bakri', 'Amir Hossein', 'Kumaran', 'Wong Kim Mun']"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#Slicing with just the : symbol returns the entire list\n",
    "customers[:]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Fikri Bakri', 'Amir Hossein', 'Kumaran']"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#Slicing first 3 elements\n",
    "customers[:3]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<font color=\"blue\">Exercise</font>: Define a function called `last_two` that accepts one argument called `inputlist`. The function should returns a new list consisting of the last two elements of `inputlist`. Please use the slice notation above. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [],
   "source": [
    "# YOUR CODE HERE\n",
    "def last_two(inputlist):\n",
    "    length = len(inputlist)\n",
    "    return inputlist[length-2:]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Delete List Elements\n",
    "To remove a list element."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Fikri Bakri', 'Amir Hossein', 'Lim Pak Hon', 'Kumaran', 'Wong Kim Mun']"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "customers"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Fikri Bakri', 'Amir Hossein', 'Kumaran', 'Wong Kim Mun']"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "del customers[2]\n",
    "customers"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Append \n",
    "Appends new element to list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "customers.append('Mohd Arif')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "customers"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "customers = customers + ['samuel','Amirul']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "customers"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### In\n",
    "Use in Check if an element in a list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "'Amir Hossein' in customers"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "if customers == customers :\n",
    "    print(\"customer == customer\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "customers == ['a','b','c']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Remove\n",
    "Remove an element in the list if you do not know the index."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "customers.remove('Amir Hossein')\n",
    "customers"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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