Coding Activities for Schools/National 4/Array_Nat_4.ipynb

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   "metadata": {},
   "source": [
    "# Array programming exercises"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Legend"
   ]
  },
  {
   "cell_type": "markdown",
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   "source": [
    "<div class = \"alert alert-block alert-info\">\n",
    "    In <b> blue</b>, the <b> instructions </b> and <b> goals </b> are highlighted.\n",
    "</div>"
   ]
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  {
   "cell_type": "markdown",
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   "source": [
    "<div class = \"alert alert-block alert-success\">\n",
    "    In <b> green</b>, the <b> information </b> is highlighted.\n",
    "</div>"
   ]
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "    In <b> yellow</b>, the <b> exercises </b> are highlighted.\n",
    "</div>"
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    "<div class = \"alert alert-block alert-danger\">\n",
    "    In <b> red</b>, the <b> error </b> and <b> alert messages </b> are highlighted.\n",
    "</div>"
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Instructions"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-info\">\n",
    "    Click <b> Run </b> on each cell to go through the code in each cell. This will take you through the cell and print out the results. \n",
    "    If you wish to see all the outputs at once in the whole notebook, just click <b> Cell </b> and then <b> Run All. </b>\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Goals"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-info\">\n",
    "After this workshop, the student should get more familiar with the following topics: <br> \n",
    "<ul>\n",
    "    <li> printing basic statements and commands in Jupyter Notebook</li>\n",
    "    <li> performing basic arithmetic calculations in Python</li>\n",
    "    <li> improving an existent model of the code</li>\n",
    "    <li> recognizing and checking variable types in Python </li>\n",
    "    <li> using the <b> if </b> and <b> for </b> statements for basic operations\n",
    "    <li> working with array data structure as a way of storing the data\n",
    "</ul>\n",
    "    \n",
    "<b> These objectives are in agreement with the National 3 Scottish Curriculum for high-school students. </b> <br> <br> <b> Note: </b> For most of the workshop, the student will be given some coding examples. In some cases, the student will have to code himself/herself. The coding part is optional, but highly recommended to approach. \n",
    "  \n",
    "</div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Explore..."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-success\">\n",
    "Welcome to another session on the Jupyter Notebooks!! Today we will focus on working with <b> arrays. </b> They are a fundamental data structure used in every possible programming language. The array represents the most basic data structure existent in programming, which is the most basic way to store data and access it whenevr you want. \n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "my_first_array = [1,2,3,4,5,6]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "You have just declared your first array! Do you want to see how it looks?"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3, 4, 5, 6]"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "my_first_array"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> Inspect the following code lines below and see what they do: \n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "my_first_array[0]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "my_first_array[1]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-success\">\n",
    "    By putting the [ ] bracket, we are able to access each element of the array. The digit inside the bracket [] stands for the position of the element. <b> Remember: </b> similar to the loops in the for-instruction, the first element takes position 0, the second element takes position 1, and so on...\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> Inspect now the following code. <b> Predict </b> the output of the code, then <b> run </b> it:\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "6"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "len(my_first_array)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-success\">\n",
    "    Each array is characterized by a <b> length</b>. The <b> length of an array </b> is defined by the number of the elements inside the array.\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> Can you access the last element of my_first_array? Of course, you already know all the elements, and you also know the length of the array:\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Write your code here (You only need one line of code)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> what happens when we type the following?\n",
    "     </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "ename": "IndexError",
     "evalue": "list index out of range",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mIndexError\u001b[0m                                Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-7-4c4a489cefcf>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mmy_first_array\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m6\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;31mIndexError\u001b[0m: list index out of range"
     ]
    }
   ],
   "source": [
    "my_first_array[6]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-danger\">\n",
    "This is a classic error, which you will encounter countless times in programming: <b> list index out of range</b>. If the index of the first element is 0, and the array has 6 elements, then of course the index of the last element will be 5: 0,1,2,3,4,5, there are indeed 6 elements.\n",
    " </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "my_first_array[5]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-success\">\n",
    "<b> Hint: </b> Pyhton language also supports the printing of last element of a loop in a different way\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "my_first_array[-1]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> Now let us try and work more with an array. Suppose we want to go through an array and print each element. The procedure is quite similar to the for-instruction exercises (you can revisit hem at any time you desire)\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for i in range(my_first_array)\n",
    "    print(my_first_array[0])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-danger\">\n",
    "    Never forget the sign <b> : </b> when working with the <b> for </b> instruction. The <b> invalid syntax error </b> is yet another error which will be encountered countless times:\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for i in range(len(my_first_array)):\n",
    "    print(my_first_array[i])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "    <b> Exercise: </b> print all the elements of the array in a horizontal line\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Write your own code here"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "    <b> Exercise: </b> check that any element of the array is an integer (try with the first element)\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Write your own code here"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "    <b> Exercise: </b> <b> Inspect </b> the following code below, and see what it does. <b> Spend </b> a bit of time on it, <b> analyse </b> it, <b> discuss </b> it amongst yourselves and with the teacher. Make sure you understand what is going on, as there are some subtleties here:\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "sum = 0\n",
    "for i in range(len(my_first_array)):\n",
    "    sum += my_first_array[i]\n",
    "    \n",
    "sum"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If we want to check how the computer is thinking, we can outline the following extension, similar to a copy-paste:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "sum = 0\n",
    "i = 0\n",
    "print(\"The sum of the first \" + str(i+1) + \" elements is: \" + str(sum))\n",
    "i += 1\n",
    "sum += i\n",
    "print(\"The sum of the first \" + str(i+1) + \" elements is: \" + str(sum))\n",
    "i += 1\n",
    "sum += i\n",
    "print(\"The sum of the first \" + str(i+1) + \" elements is: \" + str(sum))\n",
    "i += 1\n",
    "sum += i\n",
    "print(\"The sum of the first \" + str(i+1) + \" elements is: \" + str(sum))\n",
    "i += 1\n",
    "sum += i\n",
    "print(\"The sum of the first \" + str(i+1) + \" elements is: \" + str(sum))\n",
    "i += 1\n",
    "sum += i\n",
    "print(\"The sum of the first \" + str(i+1) + \" elements is: \" + str(sum))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "    <b> Inspect </b> the two following expressions, and make sure you understand that they are the same: $ a += 1 $ and $ a = a + 1 $\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "a = 0\n",
    "a += 1\n",
    "print(\"The value of a after the first operation is: \" + str(a))\n",
    "a = a + 1\n",
    "print(\"The value of a after the second operation is: \" + str(a))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Analyse: </b> For the calculation of sum within the loop, what happens if I put the sum variable <b> inside </b> the for instruction?\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for i in range(len(my_first_array)):\n",
    "    sum = 0\n",
    "    sum += my_first_array[i]\n",
    "    \n",
    "sum"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-danger\">\n",
    "    The sum variable is set to 0 after each step, or <b> iteration</b>. For each time, the sum is added to a new value of i, and then set to 0, and so on, until it reaches the last element. In the end, the code just prints out the maximum value that variable <b> i </b> takes.\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> Using the above model, calculate the product of all elements in the array. Discuss this exercise among yourselves and with the teacher, for the right guidance. Bear in mind that you will use the neutral element for <b> multiplication</b>, not <b> addition</b>, this time (What did I mean by this?)\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Write your own code here"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-success\">\n",
    "    Now, we would like to <b> append </b> some elements to the array. Think of appending just as in the Snake game. Whenever the snake eats an apple, its tail grows: an element is <b> appended </b>, or added to the tail. \n",
    "    </div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> Inspect the code below: predict its output by discussing with your colleagues, and run the cell afterwards. Moreover, run that particular cell more times: what happens?\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3, 4, 5, 6, 7, 7]"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "my_first_array.append(7)\n",
    "my_first_array"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-danger\">\n",
    "    Whenever you run the cell, another element is added! If you want to add the element only once, do not run the cell more times. \n",
    "    </div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-warning\">\n",
    "<b> Exercise: </b> Add more elements in the array: from 8 to 12. WHat happens if you run the cell more times?\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Write your own code here"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Take-away"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class = \"alert alert-block alert-info\">\n",
    "\n",
    "This is it for today, and well done for managing to go through the material!! <br> <br> After this session, you should be more familiar with how simple sentences, numbers and conditional statements can be printed in Python. Moreover, ponder a bit on the for instruction, as it is heavily used in programming, as well as the numerical algorithms involved here, and how you can go through an array. Also, feel free to work more on this notebook using any commands you would like. <br> <br>\n",
    "<b> Note: </b> Always keep a back-up of the notebook, in case the original one is altered. <br><br>\n",
    "For today's session, this should be enough! See you later!!\n",
    "    </div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(\"Bye bye! :D\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "![Noteable license](https://github.com/jstix/mr-noteable/blob/master/Banner%20image/Screenshot%202021-03-05%20115453.png?raw=true)"
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