Third lab lecture updated

Author: arcangelo7

laboratory/docs/chapter/03.md

@@ -4,48 +4,93 @@
 Similar to lists, but their values can’t be modified
 
 ```py
-numbers = (10,30,50,70)
+numbers = (10, 30, 50, 70)
 print(numbers[2])
 
-#ERROR: assignment is not allowed
+# TypeError: 'tuple' object does not support item assignment
 numbers[2] = 55
 ```
 
-## Loops: "while" and "for"
+A special problem is the construction of tuples containing 0 or 1 items: the syntax has some extra quirks to accommodate these. Empty tuples are constructed by an empty pair of parentheses; a tuple with one item is constructed by following a value with a comma (it is not sufficient to enclose a single value in parentheses). Ugly, but effective. For example:
 
-* Loops are used in order to repeat similar actions
-* We can't loop forever this will make our program crash
-* Our loops need a rule/condition that defines when they need to stop
+```py
+empty = ()
+singleton = 'hello',    # <-- note trailing comma
+len(empty) 
+# 0
+len(singleton)
+# ('hello',)
+```
 
-### The "while" statement
+## The "for" statement
+
+Python's for statement iterates over the items of any sequence (e.g., strings, lists, tuples), in the order that they appear in the sequence.
+
+```py
+# What is the thickness of a sheet of paper folded 10 times?
+
+times = [1,2,3,4,5,6,7,8,9,10]
+thickness = 0.1
+for i in times:
+    thickness *= 2
+print(thickness)
+# 102.4
+```
+
+If you do need to iterate over a sequence of numbers, the built-in function `range()` comes in handy. It generates arithmetic progressions.
+
+```py
+# What is the thickness of a sheet of paper folded 39 times?
+
+thickness = 0.1
+for i in range(39):
+    thickness *= 2
+print(thickness)
+# 54975581388.8 cm = 549755.813888 Km
+# Which is more than the distance between the Earth and the Moon (384400 Km)
+```
+
+The given end point is never part of the generated sequence; `range(10)` generates 10 values, the legal indices for items of a sequence of length 10. It is possible to let the range start at another number, or to specify a different increment (even negative; sometimes this is called the 'step'):
 
 ```py
-a = 0
-while a < 10 :
-    print(a)
-    a += 1
+list(range(5, 10))
+# [5, 6, 7, 8, 9]
+
+list(range(0, 10, 3))
+# [0, 3, 6, 9]
+
+list(range(-10, -100, -30))
+# [-10, -40, -70]
 ```
 
-### The "for" statement
+### The "while" statement
+
+The while statement is used for repeated execution as long as an expression is true.
 
-* Repeat the inner code for a number of times
-* We use it when we already know how many times/repetitions we need to execute our code
-* In python a for loop is done its execution when it finishes iterating a given sequence
+We generally use this loop when we don't know the number of times to iterate beforehand.
 
 ```py
-for a in range(0,10):
-    print(a)
+distance_earth_moon = 38440000000
+thickness = 0.1
+times = 0
+while thickness < distance_earth_moon:
+    thickness *= 2
+    times += 1
+print(times)
+# 39
 ```
 
+Make sure that the while loop condition becomes false at some point, otherwise, the loop will continue forever (or until the PC crashes or the laptop battery runs out)
+
 ## Exercises
 
 ### 1st Exercise
 Let's pretend we have a list containing the titles of all the Computational Thinking lessons. The list is ordered following the established schedule. Below is the list:
 ```py
-l_schedule = ["Introduction to the course","Introduction to Computational Thinking","Algorithms","Laboratory","Computability","Programming languages","Organising information: ordered structures","Laboratory","Brute-force algorithms","Laboratory","Organising information: unordered structures","Laboratory","Recursion","Laboratory","Divide and conquer algorithms","Laboratory","Dynamic programming algorithms","Organising information: trees","Backtracking algorithms","Organising information: graphs","Greedy algorithms"]
+ctp_lessons = ["Introduction to the course","Introduction to Computational Thinking","Algorithms","Laboratory","Computability","Programming languages","Organising information: ordered structures","Laboratory","Brute-force algorithms","Laboratory","Organising information: unordered structures","Laboratory","Recursion","Laboratory","Divide and conquer algorithms","Laboratory","Dynamic programming algorithms","Organising information: trees","Backtracking algorithms","Organising information: graphs","Greedy algorithms"]
 ```
 
-**1.a)** Define a function named <code class="py">lab_lessons()</code> which takes <code class="py">l_schedule</code> as a parameter and returns the total number of <code class="py">"Laboratory"</code> lessons.
+**1.a)** Define a function named <code class="py">lab_lessons()</code> which takes <code class="py">ctp_lessons</code> as a parameter and returns the total number of <code class="py">"Laboratory"</code> lessons.
 
 <button class="toggle-solution btn btn-light" onclick="toggle_click(this,'sol_3_1a')">Show solution</button>
 <div class="solution-code" id="sol_3_1a">
@@ -59,7 +104,7 @@ def lab_lessons(a_list):
 ```
 </div>
 
-**1.b)** Define a function named <code class="py">all_before_lab()</code> which takes <code class="py">l_schedule</code> as a parameter and returns a list containing all the lessons scheduled before the first <code class="py">"Laboratory"</code> lesson.
+**1.b)** Define a function named <code class="py">all_before_lab()</code> which takes <code class="py">ctp_lessons</code> as a parameter and returns a list containing all the lessons scheduled before the first <code class="py">"Laboratory"</code> lesson.
 
 <button class="toggle-solution btn btn-light" onclick="toggle_click(this,'sol_3_1b')">Show solution</button>
 <div class="solution-code" id="sol_3_1b">
@@ -76,13 +121,13 @@ def all_before_lab(a_list):
 ```
 </div>
 
-**1.c)** Let's pretend we have a new list representing an extended version of the <code class="py">l_schedule</code>, such that it embeds information about the date, time and the duration (in hours) of the each lesson. We call the new list <code class="py">l_schedule_extended</code>. Each element is represented as a tuple: <code class="py">([HOURS],[DATE],[TIME],[TITLE])</code>. For instance, the third lesson "Algorithms" will have the corresponding tuple: <code class="py">(2,"15/10/21","12:30-14:30","Algorithms")</code>. Here we have the entire <code class="py">l_schedule_extended</code>:
+**1.c)** Let's pretend we have a new list representing an extended version of the <code class="py">ctp_lessons</code>, such that it embeds information about the date, time and the duration (in hours) of the each lesson. We call the new list <code class="py">ctp_lessons_extended</code>. Each element is represented as a tuple: <code class="py">([HOURS],[DATE],[TIME],[TITLE])</code>. For instance, the third lesson "Algorithms" will have the corresponding tuple: <code class="py">(2,"15/10/21","12:30-14:30","Algorithms")</code>. Here we have the entire <code class="py">ctp_lessons_extended</code>:
 
 ```py
-l_schedule_extended = [(2,"11/10/21","09:30-11:30","Introduction to the course"),(2,"13/10/21","09:30-11:30","Introduction to Computational Thinking"),(2,"15/10/21","12:30-14:30","Algorithms"),(2,"18/10/21","09:30-11:30","Laboratory"),(2,"20/10/21","09:30-11:30","Computability"),(2,"22/10/21","12:30-14:30","Programming languages"),(2,"25/10/21","09:30-11:30","Organising information: ordered structures"),(2,"27/10/21","09:30-11:30","Laboratory"),(2,"29/10/21","12:30-14:30","Brute-force algorithms"),(2,"08/11/21","09:30-11:30","Laboratory"),(2,"10/11/21","09:30-11:30","Organising information: unordered structures"),(2,"15/11/21","09:30-11:30","Laboratory"),(2,"17/11/21","09:30-11:30","Recursion"),(2,"22/11/21","09:30-11:30","Laboratory"),(2,"24/11/21","09:30-11:30","Divide and conquer algorithms"),(2,"29/11/21","09:30-11:30","Laboratory"),(2,"01/12/21","09:30-11:30","Dynamic programming algorithms"),(2,"06/12/21","09:30-11:30","Organising information: trees"),(2,"13/12/21","09:30-11:30","Backtracking algorithms"),(2,"15/12/21","09:30-11:30","Organising information: graphs"),(2,"20/12/21","09:30-11:30","Greedy algorithms")]
+ctp_lessons_extended = [(2,"12/10/22","09:30-11:30","Introduction to the course"),(2,"14/10/22","12:30-14:30 ","Introduction to Computational Thinking"),(2,"17/10/22","09:30-11:30","Algorithms"),(2,"19/10/22","09:30-11:30","Laboratory"),(2,"21/10/22","12:30-14:30","Computability"),(2,"24/10/22","09:30-11:30","Programming languages"),(2,"26/10/22","09:30-11:30","Laboratory"),(2,"28/10/22","12:30-14:30","Organising information: ordered structures"),(2,"09/11/22","09:30-11:30","Brute-force algorithms"),(2,"11/11/22","12:30-14:30","Laboratory"),(2,"14/11/22","09:30-11:30","Organising information: unordered structures"),(2,"16/11/22","09:30-11:30","Laboratory"),(2,"21/11/22","09:30-11:30","Recursion"),(2,"23/11/22","09:30-11:30","Divide and conquer algorithms"),(2,"28/11/22","09:30-11:30","Laboratory"),(2,"30/11/22","09:30-11:30","Dynamic programming algorithms"),(2,"05/12/22","09:30-11:30","Laboratory"),(2,"12/12/22","09:30-11:30","Organising information: trees"),(2,"14/12/22","09:30-11:30","Backtracking algorithms"),(2,"19/12/22","09:30-11:30","Organising information: graphs"),(2,"21/12/22","09:30-11:30","Greedy algorithms")]
 ```
 
-Define a function <code class="py">max_lessons_hours()</code> which takes <code class="py">l_schedule_extended</code> and a number <code class="py">max_hours</code> as parameters, and returns a list containing only the titles of all the lessons which could be attended with a maximum number of hours = <code class="py">max_hours</code>, starting from the first lesson of the year.
+Define a function <code class="py">max_lessons_hours()</code> which takes <code class="py">ctp_lessons_extended</code> and a number <code class="py">max_hours</code> as parameters, and returns a list containing only the titles of all the lessons which could be attended with a maximum number of hours = <code class="py">max_hours</code>, starting from the first lesson of the year.
 
 <button class="toggle-solution btn btn-light" onclick="toggle_click(this,'sol_3_1c')">Show solution</button>
 
@@ -101,20 +146,23 @@ def max_lessons_hours(a_list, max_hours):
 ```
 </div>
 
-**1.d)** One of the students attending the course, Tim Berners Lee, thinks he knows enough about the materials taught in the course, so he will take a break and go for a vacation on 12/11/21 for 2 weeks. Right after that, when he gets back he will attend again the lectures starting from the first available one according to the schedule until the end of the course. Write down a portion of code that prints the titles of the lectures that Tim Berners Lee will attend at the end of the course.  
+**1.d)** One of the students attending the course, Tim Berners Lee, thinks he knows enough about the materials taught in the course, so he will take a break and go on a vacation on 12/11/21 for two weeks. Right after that, when he returns, he will attend the lectures again, starting from the first available one according to the schedule until the end of the course. Write down a portion of the code that prints the titles of the lectures that Tim Berners Lee will attend at the end of the course.
+
 **Hint:** take a look at the `datetime` library
 
 <button class="toggle-solution btn btn-light" onclick="toggle_click(this,'sol_3_1d')">Show solution</button>
 <div class="solution-code" id="sol_3_1d">
 ```py
-vacation_date = datetime.datetime.strptime("12/11/21", '%d/%m/%y')
+from datetime import datetime
+
+vacation_date = datetime.strptime("12/11/21", '%d/%m/%y')
 back_date = vacation_date + datetime.timedelta(weeks=2)
 result = []
 i = 0
-for lesson_tuple in l_schedule_extended:
+for lesson_tuple in ctp_lessons_extended:
     lesson_date = datetime.datetime.strptime(lesson_tuple[1], '%d/%m/%y')
     if lesson_date < vacation_date or lesson_date > back_date:
         result.append(lesson_tuple[3])
 print(result)
 ```
-</div>
+</div>

laboratory/site/chapter/01/index.html

@@ -141,20 +141,20 @@ <h2 id="check-if-python-is-already-installed">Check if Python is already install
 In computing, a <a href="https://en.wikipedia.org/wiki/Shell_(computing)">shell</a> is a user interface for accessing the services of an operating system. It can be a <a href="https://en.wikipedia.org/wiki/Command-line_interface">command-line interface (CLI)</a> or a <a href="https://en.wikipedia.org/wiki/Graphical_user_interface">graphical user interface (GUI)</a>. It enables a user to perform several operations, such as file management, installations, running processes, monitoring and configuring an OS. We will use it to install packages and as an interpreter for Python.
 </span></p>
 <h3 id="open-the-command-line-interface-cli">Open the Command Line Interface (CLI)</h3>
-<h4>Windows</h4>
+<h4 id="windows">Windows</h4>
 <ul>
 <li>Open the Windows menu</li>
 <li>Type <em>"powershell"</em> in the search bar</li>
 <li>Select <strong>Windows PowerShell</strong> from the search results</li>
 </ul>
-<h4>macOS</h4>
+<h4 id="macos">macOS</h4>
 <ul>
 <li>Open the Spotlight search box in the upper right-hand corner</li>
 <li>Type <em>"terminal"</em> in the search bar</li>
 <li>Click on <strong>Terminal</strong> or just hit return if it is the first result</li>
 </ul>
 <p><span class="note">Alternatively, go to the directory <span class="dir">Applications/Utility</span> and open <strong>Terminal</strong> application.</span></p>
-<h4>Linux (Ubuntu)</h4>
+<h4 id="linux-ubuntu">Linux (Ubuntu)</h4>
 <ul>
 <li>Open the applications drawer</li>
 <li>Type <em>"terminal"</em> or <em>"konsole"</em> in the search bar</li>
@@ -168,10 +168,9 @@ <h3 id="check-the-python-version">Check the Python version</h3>
 <pre><code>python --version
 Python 2.7.3
 </code></pre>
-
 <p>Try to type <code>python3 --version</code> (also <code>python3 -V</code> on Windows) in the command line, then press return to check whether you have Python 3 installed, and eventually the last version.</p>
 <h2 id="download-and-install-python">Download and install Python</h2>
-<h4>Windows</h4>
+<h4 id="windows_1">Windows</h4>
 <ul>
 <li>Go to the <a href="https://www.python.org/downloads/">Python download page</a></li>
 <li>Click on the download button to get the latest version of <strong>Python</strong></li>
@@ -189,15 +188,15 @@ <h4>Windows</h4>
 <li>Click on the <strong>Install</strong> button, and wait until the end of the installation</li>
 <li>Finally, go to the command line and try to type <code>python --version</code> (also <code>python3 -V</code>) and press return to check whether you correctly installed Python.</li>
 </ul>
-<h4>macOS</h4>
+<h4 id="macos_1">macOS</h4>
 <ul>
 <li>Go to the <a href="https://www.python.org/downloads/">Python download page</a></li>
 <li>Click on the download button to get the latest version of <strong>Python</strong></li>
 <li>Double-click on the downloaded .pkg file to start the installation</li>
 <li>Follow the step-by-step guidelines</li>
 <li>Finally, go to the command line and try to type <code>python --version</code> (also <code>python3 --version</code> in case you have also Python 2) and press return to check whether you correctly installed Python</li>
 </ul>
-<h4>Linux (Ubuntu)</h4>
+<h4 id="linux-ubuntu_1">Linux (Ubuntu)</h4>
 <ul>
 <li>Open the Command Line Interface (Terminal or Console)</li>
 <li>Type <code>sudo apt-get update</code></li>
@@ -217,7 +216,6 @@ <h3 id="play-with-python-in-the-shell">Play with Python in the shell</h3>
 <pre><code>&gt;&gt;&gt; print(&quot;Hello world&quot;)
 Hello World
 </code></pre>
-
 <ul>
 <li>Type <code>exit()</code> and press enter to exit from the python interactive mode.</li>
 </ul>
@@ -247,23 +245,23 @@ <h3 id="install-modules-with-pip3">Install modules with pip3</h3>
 </ul>
 <h2 id="install-the-editor-visual-studio-code">Install the editor: Visual Studio Code</h2>
 <p>Programming using the shell interpreter is convenient for small tests but impractical for developing complex applications. For this reason, special editors, called <a href="https://en.wikipedia.org/wiki/Integrated_development_environment">integrated development environments</a> (IDE), are used. For Python, the most widely used IDEs are Visual Studio Code, PyCharm and Atom. We suggest using Visual Studio Code for this course.</p>
-<h4>Windows</h4>
+<h4 id="windows_2">Windows</h4>
 <ul>
 <li>Download the <a href="https://code.visualstudio.com/docs?dv=win">Visual Studio Code installer</a> for Windows.</li>
 <li>Run the downloaded installer (VSCodeUserSetup-{version}.exe). This will only take a minute</li>
 <li>By default, VS Code is installed under <span class="dir">C:\users{username}\AppData\Local\Programs\Microsoft VS Code</span>  </li>
 </ul>
 <p><span class="note"><strong>Note:</strong> .NET Framework 4.5.2 or higher is required for VS Code. If you are using Windows 7, make sure you have at least <a href="https://www.microsoft.com/download/details.aspx?id=42643">.NET Framework 4.5.2</a> installed. You can check your version of .NET Framework using this command, <code>reg query "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\full" /v version</code> from a command prompt.</span></p>
 <p><span class="note"><strong>Note:</strong> you can find more details at <a href="https://code.visualstudio.com/docs/setup/windows">https://code.visualstudio.com/docs/setup/windows</a></span></p>
-<h4>macOS</h4>
+<h4 id="macos_2">macOS</h4>
 <ul>
 <li>Download <a href="https://go.microsoft.com/fwlink/?LinkID=534106">Visual Studio Code</a> for macOS.</li>
 <li>Open the browser's download list and locate the downloaded archive.</li>
 <li>Extract the contents of the downloaded archive. (usually with a double-click)</li>
 <li>Drag <strong>Visual Studio Code.app</strong> to the Applications folder, making it available in the macOS Launchpad.</li>
 </ul>
 <p><span class="note"><strong>Note:</strong> you can find more details at <a href="https://code.visualstudio.com/docs/setup/mac">https://code.visualstudio.com/docs/setup/mac</a></span></p>
-<h4>Linux</h4>
+<h4 id="linux">Linux</h4>
 <p>For Debian/Ubuntu based distributions, download and install the <a href="https://go.microsoft.com/fwlink/?LinkID=760868">.deb package (64-bit)</a>, either through the graphical software center if it's available, or through the command line with: <code>sudo apt install ./&lt;file&gt;.deb</code></p>
 <p><span class="note"><strong>Note:</strong> you can find more details and guidelines for other linux distributions at <a href="https://code.visualstudio.com/docs/setup/linux">https://code.visualstudio.com/docs/setup/linux</a></span></p>
 <h2 id="create-and-run-a-python-script-in-visual-studio-code">Create and run a Python script in Visual Studio Code</h2>
@@ -290,9 +288,8 @@ <h3 id="create-and-run-the-first-python-script">Create and run the first Python
 <!-- <button class="toggle-solution btn btn-light" onclick="toggle_click(this,'sol_1')">Show solution</button>s
 ```{.python .code-overflow-wrap .solution-code #sol_1}-->
 
-<pre><code class="py">print(&quot;Hello World !!&quot;)
+<pre><code class="language-py">print(&quot;Hello World !!&quot;)
 </code></pre>
-
 <ul>
 <li>Run the script by clicking on the menu arrow near the run button and selecting <strong>Run Python File in Terminal</strong><br />
 <img src="../img/vsc_run.png"></li>