Created on Skills Network Labs

List_exercises.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "A list is a sequenced collection of different objects such as integers, strings, and other lists as well.\n",
    "\n",
    "An index is used to access and refer to items within a list."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Michael Jackson', 10.1, 1982]"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#A list is created within square brackets [ ]\n",
    "\n",
    "L = [\"Michael Jackson\", 10.1, 1982]\n",
    "L"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Indexing the above list L, we can index them as 0, 1, 2...respective.\n",
    "                           We can also index the list in negavite as -3, -2, -1.....respectively."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "the same element using negative and positive indexing:\n",
      " Postive: Michael Jackson \n",
      " Negative: Michael Jackson\n"
     ]
    }
   ],
   "source": [
    "print('the same element using negative and positive indexing:\\n Postive:',L[0],\n",
    "'\\n Negative:' , L[-3]  )"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "the same element using negative and positive indexing:\n",
      " Positve: 10.1 \n",
      " Negative: 10.1\n",
      "the same element using negative and positive indexing:\n",
      " Postive: 1982 \n",
      " Negative: 1982\n"
     ]
    }
   ],
   "source": [
    "print('the same element using negative and positive indexing:\\n Positve:', L[1],\n",
    "     '\\n Negative:', L[-2] )\n",
    "print('the same element using negative and positive indexing:\\n Postive:',L[2],\n",
    "'\\n Negative:' , L[-1]  )"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Lists can contain strings, floats, and integers. It can also nest Tuples and other data structures."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Michael Jackson', 10.1, 1982, [1, 2], ('A', 1)]"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "L = [\"Michael Jackson\", 10.1, 1982, [1, 2], (\"A\", 1)]\n",
    "L"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[[1, 2], ('A', 1)]"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#List slicing...... e.g., to access the last two elements.\n",
    "L[3:5]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "In List, we use .extend to add new elements to a list."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Michael Jackson', 10.1, 1982, [1, 2], ('A', 1), 'pop', 10]"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "L.extend (['pop', 10])\n",
    "L"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Michael Jackson', 10.1, 1982, [1, 2], ('A', 1), 'pop', 10, ['a', 'b']]"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#With .append, we can add a nested list to a list.\n",
    "\n",
    "L.append(['a','b'])\n",
    "L"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "lists are mutable, we can change them"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Before change: ['disco', 10, 1.2]\n",
      "After change: ['hard rock', 10, 1.2]\n"
     ]
    }
   ],
   "source": [
    "A = [\"disco\", 10, 1.2]\n",
    "print('Before change:', A)\n",
    "A[0] = 'hard rock'\n",
    "print('After change:', A)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can also delete an element of a list using the 'del' command:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Before change: ['hard rock', 10, 1.2]\n",
      "After change: [10, 1.2]\n"
     ]
    }
   ],
   "source": [
    "print('Before change:', A)\n",
    "del(A[0])\n",
    "print('After change:', A)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can convert a string to a list using .split function in python"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['hard', 'rock']"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#e.g., we can split the string 'hard rock' to hard, rock using the .split function\n",
    "'hard rock'.split()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can use the split function to separate strings on a specific character, and turn them to make a list."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['A', 'B', 'C', 'D']"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'A,B,C,D'.split(',')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can copy and clone in List such that:\n",
    "When we set one variable B equal to A; both A and B are referencing the same list in memory:\n",
    "e.g., see the example below."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "A: ['hard rock', 10, 1.2]\n",
      "B: ['hard rock', 10, 1.2]\n"
     ]
    }
   ],
   "source": [
    "A = [\"hard rock\", 10, 1.2]\n",
    "B = A\n",
    "print('A:', A)\n",
    "print('B:', B)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "B[0]: hard rock\n",
      "B[0]: banana\n"
     ]
    }
   ],
   "source": [
    "#As A and B are referencing the same list, if we change list A, then list B also changes\n",
    "\n",
    "print('B[0]:', B[0])\n",
    "A[0] = \"banana\"\n",
    "print('B[0]:', B[0])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "In the example below, We can clone list A by using the following syntax:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['banana', 10, 1.2]"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#such that Variable B references a new copy or clone of the original list in A;\n",
    "\n",
    "B = A[:]\n",
    "B"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "B[0]: banana\n",
      "B[0]: banana\n"
     ]
    }
   ],
   "source": [
    "#since variable B is now a clone copy of A, any changes in A will not affect B\n",
    "\n",
    "print('B[0]:', B[0])\n",
    "A[0] = 'hard rock'\n",
    "print('B[0]:', B[0])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "A: ['hard rock', 10, 1.2]\n",
      "B: ['banana', 10, 1.2]\n"
     ]
    }
   ],
   "source": [
    "print ('A:', A)\n",
    "print ('B:', B)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "A task to create on list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 'hello', [1, 2, 3], True]"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#Create a random list composed of all popular data stuctures\n",
    "\n",
    "a_list = [1, 'hello', [1, 2, 3], True]\n",
    "a_list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['hello', [1, 2, 3], True]"
      ]
     },
     "execution_count": 25,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#retrieving the elements stored at index 1, 2, and 3.\n",
    "a_list[1:4]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [],
   "source": [
    "A = [1, 'A']\n",
    "B = [2, 1, 'd']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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