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HTML

              
                <script src="https://cdn.freecodecamp.org/testable-projects-fcc/v1/bundle.js"></script>
<nav id="navbar">
      <header id="main-header">
        <h1>Python Tutorial</h1>
      </header>
      <ul>
        <li>
          <a href="#Introduction" class="nav-link active">Introduction</a>
        </li>
        <li><a href="#Getting_Started" class="nav-link">Getting Started</a></li>
        <li><a href="#Syntax" class="nav-link">Syntax</a></li>
        <li><a href="#Comments" class="nav-link">Comments</a></li>
        <li><a href="#Variables" class="nav-link">Variables</a></li>
        <li><a href="#Reference" class="nav-link">Reference</a></li>
      </ul>
    </nav>

    <main id="main-doc">
      <section class="main-section" id="Introduction">
        <header>
          <h2>Introduction</h2>
        </header>
        <article>
          <p>
            Python is a popular programming language. It was created by Guido
            van Rossum, and released in 1991.
            <span class="new-line"></span> It is used for:
          </p>
          <ul>
            <li>web development (server-side),</li>
            <li>software development,</li>
            <li>mathematics,</li>
            <li>system scripting.</li>
          </ul>
        </article>
        <article>
          <h3>What can Python do?</h3>
          <ul>
            <li>Python can be used on a server to create web applications.</li>
            <li>Python can be used alongside software to create workflows.</li>
            <li>
              Python can connect to database systems. It can also read and
              modify files.
            </li>
            <li>
              Python can be used to handle big data and perform complex
              mathematics.
            </li>
            <li>
              Python can be used for rapid prototyping, or for production-ready
              software development.
            </li>
          </ul>
        </article>
        <article>
          <h3>Why Python?</h3>
          <ul>
            <li>
              Python works on different platforms (Windows, Mac, Linux,
              Raspberry Pi, etc).
            </li>
            <li>Python has a simple syntax similar to the English language.</li>
            <li>
              Python has syntax that allows developers to write programs with
              fewer lines than some other programming languages.
            </li>
            <li>
              Python runs on an interpreter system, meaning that code can be
              executed as soon as it is written. This means that prototyping can
              be very quick.
            </li>
            <li>
              Python can be treated in a procedural way, an object-orientated
              way or a functional way.
            </li>
          </ul>
        </article>
      </section>

      <section class="main-section" id="Getting_Started">
        <header>
          <h2>Getting Started</h2>
        </header>
        <article>
          <h3>Python install</h3>
          <p>
            Many PCs and Macs will have python already installed.
            <span class="new-line"></span>
            To check if you have python installed on a Windows PC, search in the
            start bar for Python or run the following on the Command Line
            (cmd.exe):
            <code class="console">C:\Users\Your Name>python --version</code>
            <span class="new-line"></span> check if you have python installed on
            a Linux or Mac, then on linux open the command line or on Mac open
            the Terminal and type:
            <code class="console">python --version</code>
          </p>
        </article>
        <article>
          <h3>Python Quickstart</h3>
          <p>
            Python is an interpreted programming language, this means that as a
            developer you write Python (.py) files in a text editor and then put
            those files into the python interpreter to be executed.
            <span class="new-line"></span> way to run a python file is like this
            on the command line:
            <code class="console">C:\Users\Your Name>python helloworld.py</code>
            <span class="new-line"></span> "helloworld.py" is the name of your
            python file. <span class="new-line"></span>Let's write our first
            Python file, called helloworld.py, which can be done in any text
            editor.
            <code class="editor"
              ><span class="keyword">print</span>(<span class="str"
                >"Hello, World!"</span
              >)</code
            >
            <span class="new-line"></span> as that. Save your file. Open your
            command line, navigate to the directory where you saved your file,
            and run:
            <code class="console">C:\Users\Your Name>python helloworld.py</code>
            <span class="new-line"></span> output should read:
            <code class="console">Hello, World!</code>
          </p>
        </article>
      </section>

      <section class="main-section" id="Syntax">
        <header>
          <h2>Syntax</h2>
        </header>
        <article>
          <h3>Execute Python Syntax</h3>
          <p>
            Python syntax can be executed by writing directly in the Command
            Line:
            <code class="console"
              >>>> print("Hello, World!")<span class="new-line"></span> Hello,
              World!</code
            >
            <span class="new-line"></span>
            Or by creating a python file on the server, using the .py file
            extension, and running it in the Command Line:
            <code class="console">C:\Users\Your Name>python myfile.py</code>
          </p>
        </article>
        <article>
          <h3>Python Indentation</h3>
          <p>
            <span class="new-line"></span> refers to the spaces at the beginning
            of a code line. <span class="new-line"></span> in other programming
            languages the indentation in code is for readability only, the
            indentation in Python is very important.
            <span class="new-line"></span> uses indentation to indicate a block
            of code.example
            <code class="editor"
              ><span class="keyword">if</span> <span class="num">5</span> >
              <span class="num">2</span>:<span class="new-line"></span>
              <span class="keyword two-word-pad-left">print</span>(<span
                class="str"
                >"Five is greater than two!"</span
              >)</code
            >
            <span class="new-line"></span> will give you an error if you skip
            the indentation: example
            <code class="editor incorrect"
              ><span class="keyword">if</span> <span class="num">5</span> >
              <span class="num">2</span>:<span class="new-line"></span>
              <span class="keyword">print</span>(<span class="str"
                >"Five is greater than two!"</span
              >)
            </code>
            <code class="console">
              <span class="one-word-pad-left"
                >File "demo_indentation_test.py", line 2</span
              ><span class="new-line"></span
              ><span class="four-word-pad-left">
                print("Five is greater than two!")</span
              ><span class="new-line"></span>
              <span class="eight-word-pad-left">^</span>
              <span class="new-line"></span>IndentationError: expected an
              indented block</code
            >
            <span class="new-line"></span> have to use the same number of spaces
            in the same block of code, otherwise Python will give you an error:
          </p>
        </article>
      </section>

      <section class="main-section" id="Comments">
        <header>
          <h2>Comments</h2>
        </header>
        <p>
          Comments can be used to explain Python code.
          <span class="new-line"></span> can be used to make the code more
          readable.
          <span class="new-line"></span>
          Comments can be used to prevent execution when testing code.
        </p>
        <article>
          <h3>Creating a Comment</h3>
          <p>
            Comments starts with a #, and Python will ignore them:Example
            <code class="editor"
              ><span class="comment">#This is a comment</span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(<span class="str"
                >"Hello, World!"</span
              >)</code
            >
          </p>
        </article>
        <article>
          <h3>Multi Line Comments</h3>
          <p>
            Python does not really have a syntax for multi line comments.
            <span class="new-line"></span>
            To add a multiline comment you could insert a # for each
            line:Example
            <code class="editor">
              <span class="comment"
                >#This is a comment<span class="new-line"></span> #written
                in<span class="new-line"></span> #more than just one line</span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(<span class="str"
                >"Hello, World!"</span
              >)
            </code>
            Or, not quite as intended, you can use a multiline string.<span
              class="new-line"
            ></span>
            Since Python will ignore string literals that are not assigned to a
            variable, you can add a multiline string (triple quotes) in your
            code, and place your comment inside it:
            <code class="editor" id="str-comment">
              """ <span class="new-line"></span>This is a comment<span
                class="new-line"
              ></span>
              written in <span class="new-line"></span>more than just one
              line<span class="new-line"></span> """<span
                class="new-line"
              ></span>
              <span class="keyword">print</span>(<span class="str"
                >"Hello, World!"</span
              >)</code
            >
          </p>
        </article>
      </section>

      <section class="main-section" id="Variables">
        <header>
          <h2>Variables</h2>
        </header>
        <article>
          <h3>Creating Variables</h3>
          <p>
            Variables are containers for storing data values.
            <span class="new-line"></span> other programming languages, Python
            has no command for declaring a variable.<span
              class="new-line"
            ></span>
            A variable is created the moment you first assign a value to
            it.Example
            <code class="editor"
              >x = <span class="num">5</span><span class="new-line"></span> y =
              <span class="str">"John"</span><span class="new-line"></span>
              <span class="keyword">print</span>(x)<span
                class="new-line"
              ></span>
              <span class="keyword">print</span>(y)</code
            >
            <span class="new-line"></span> do not need to be declared with any
            particular type and can even change type after they have been set.
            <span class="new-line"></span> variables can be declared either by
            using single or double quotes:
            <code class="editor"
              >x = <span class="str">"John"</span
              ><span class="new-line"></span>
              <span class="comment"># is the same as</span
              ><span class="new-line"></span> x =
              <span class="str">'John'</span>
            </code>
          </p>
        </article>
        <article>
          <h3>Variable Names</h3>
          <p>
            A variable can have a short name (like x and y) or a more
            descriptive name (age, carname, total_volume). Rules for Python
            variables:
          </p>
          <ul>
            <li>
              A variable name must start with a letter or the underscore
              character
            </li>
            <li>A variable name cannot start with a number</li>
            <li>
              A variable name can only contain alpha-numeric characters and
              underscores (A-z, 0-9, and _ )
            </li>
            <li>
              Variable names are case-sensitive (age, Age and AGE are three
              different variables):Example
            </li>
          </ul>
          <p>
            <code class="editor">
              <span class="comment">#Legal variable names:</span
              ><span class="new-line"></span> myvar =
              <span class="str">"John"</span>
              <span class="new-line"></span> my_var =
              <span class="str">"John"</span
              ><span class="new-line"></span> _my_var =
              <span class="str">"John"</span
              ><span class="new-line"></span> myVar =
              <span class="str">"John"</span
              ><span class="new-line"></span> MYVAR =
              <span class="str">"John"</span
              ><span class="new-line"></span> myvar2 =
              <span class="str">"John"</span><span class="new-line"></span>
              <span class="comment">#Illegal variable names:</span
              ><span class="new-line"></span>2myvar =
              <span class="str">"John"</span
              ><span class="new-line"></span> my-var =
              <span class="str">"John"</span><span class="new-line"></span> my
              var = <span class="str">"John"</span>
            </code>
          </p>
        </article>
        <article>
          <h3>Assign Value to Multiple Variables</h3>
          <p>
            <span class="new-line"></span> allows you to assign values to
            multiple variables in one line:Example
            <code class="editor"
              >x, y, z = <span class="str">"Orange", "Banana", "Cherry"</span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(x)<span
                class="new-line"
              ></span>
              <span class="keyword">print</span>(y)<span
                class="new-line"
              ></span>
              <span class="keyword">print</span>(z)</code
            >
            <span class="new-line"></span> you can assign the same value to
            multiple variables in one line:
            <code class="editor"
              >x = y = z = <span class="str">"Orange"</span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(x)<span
                class="new-line"
              ></span>
              <span class="keyword">print</span>(y)<span
                class="new-line"
              ></span>
              <span class="keyword">print</span>(z)</code
            >
          </p>
        </article>
        <article>
          <h3>Output Variables</h3>
          <p>
            <span class="new-line"></span> Python print statement is often used
            to output variables. <span class="new-line"></span> combine both
            text and a variable, Python uses the + character:
            <code class="editor"
              >x = <span class="str">"awesome"</span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(<span class="str"
                >"Python is "</span
              >
              + x)</code
            >
            <span class="new-line"></span> can also use the + character to add a
            variable to another variable:
            <code class="editor"
              >x = <span class="str">"Python is "</span
              ><span class="new-line"></span> y =
              <span class="str">"awesome"</span><span class="new-line"></span> z
              = x + y<span class="new-line"></span>
              <span class="keyword">print</span>(z)</code
            >
            <span class="new-line"></span> numbers, the + character works as a
            mathematical operator:
            <code class="editor"
              >x = <span class="num">5</span><span class="new-line"></span> y =
              <span class="num">10</span><span class="new-line"></span>
              <span class="keyword">print</span>(x + y)</code
            >
            <span class="new-line"></span> you try to combine a string and a
            number, Python will give you an error:Example
            <code class="editor"
              >x = <span class="num">5</span><span class="new-line"></span> y =
              <span class="str">"John"</span><span class="new-line"></span>
              <span class="keyword">print</span>(x + y)</code
            >
          </p>
        </article>
        <article>
          <h3>Global Variables</h3>
          <p>
            Variables that are created outside of a function (as in all of the
            examples above) are known as global variables.
            <span class="new-line"></span> variables can be used by everyone,
            both inside of functions and outside.
            <code class="editor"
              >x = <span class="str">"awesome"</span
              ><span class="new-line"></span><span class="new-line"></span>
              <span class="keyword">def</span> myfunc():<span
                class="new-line"
              ></span>
              <span class="keyword two-word-pad-left">print</span>(<span
                class="str"
                >"Python is "</span
              >
              + x)<span class="new-line"></span
              ><span class="new-line"></span> myfunc()</code
            >
            <span class="new-line"></span> you create a variable with the same
            name inside a function, this variable will be local, and can only be
            used inside the function. The global variable with the same name
            will remain as it was, global and with the original value.
            <code class="editor"
              >x = <span class="str">"awesome"</span
              ><span class="new-line"></span><span class="new-line"></span>
              <span class="keyword">def</span> myfunc():
              <span class="new-line"></span
              ><span class="two-word-pad-left">x =</span>
              <span class="str">"fantastic"</span
              ><span class="new-line"></span>
              <span class="keyword two-word-pad-left">print</span>(<span
                class="str"
              >
                "Python is "</span
              >
              + x)<span class="new-line"></span
              ><span class="new-line"></span> myfunc()<span
                class="new-line"
              ></span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(<span class="str"
                >"Python is "</span
              >
              + x)</code
            >
          </p>
        </article>
        <article>
          <h3>The global Keyword</h3>
          <p>
            Normally, when you create a variable inside a function, that
            variable is local, and can only be used inside that function.
            <span class="new-line"></span> create a global variable inside a
            function, you can use the global keyword.Example
            <code class="editor"
              ><span class="keyword">def</span> myfunc():<span
                class="new-line"
              ></span>
              <span class="keyword two-word-pad-left">global</span> x<span
                class="new-line"
              ></span>
              <span class="two-word-pad-left">x =</span>
              <span class="str">"fantastic"</span><span class="new-line"></span
              ><span class="new-line"></span> myfunc()<span
                class="new-line"
              ></span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(<span class="str"
                >"Python is "</span
              >
              + x)
            </code>
            <span class="new-line"></span>, use the global keyword if you want
            to change a global variable inside a function.Example
            <code class="editor">
              x=<span class="str">"awesome"</span><span class="new-line"></span
              ><span class="new-line"></span>
              <span class="keyword">def</span> myfunc():<span
                class="new-line"
              ></span>
              <span class="keyword two-word-pad-left">global</span> x<span
                class="new-line"
              ></span>
              <span class="two-word-pad-left">x = </span
              ><span class="str">"fantastic"</span><span class="new-line"></span
              ><span class="new-line"></span> myfunc()<span
                class="new-line"
              ></span
              ><span class="new-line"></span>
              <span class="keyword">print</span>(<span class="str"
                >"Python is "</span
              >
              + x)
            </code>
          </p>
        </article>
      </section>

      <section class="main-section" id="Reference">
        <header>
          <h2>Reference</h2>
        </header>
        <ul>
          <li>
            All the documentation in this page is taken from
            <a href="https://www.w3schools.com/python">w3schools</a>
          </li>
        </ul>
      </section>
    </main>
              
            
!

CSS

              
                :root {
  --pad-left: 10.6px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.5;
  margin: 0;
}

h2 {
  font-size: 2rem;
  font-weight: 400;
  margin-top: 0;
  padding-top: 26.56px;
}

p,
ul {
  color: #333;
}

h3 {
  padding-left: 1rem;
  font-size: 1.3rem;
  font-weight: 400;
}

p {
  padding-left: 2rem;
}

ul {
  padding-left: 4rem;
}

.one-word-pad-left {
  padding-left: var(--pad-left);
}

.two-word-pad-left {
  padding-left: calc(2 * var(--pad-left));
}

.four-word-pad-left {
  padding-left: calc(4 * var(--pad-left));
}

.eight-word-pad-left {
  padding-left: calc(8 * var(--pad-left));
}

.new-line {
  display: block;
  margin-top: 1.5em;
}

.console .new-line,
.editor .new-line {
  margin-top: initial;
}

.num {
  color: orangered;
}

.keyword {
  color: blue;
}

.str {
  color: #aa0000;
}

/* Navbar */
#navbar {
  background: rgba(0, 0, 0, 0.9);
  height: 100vh;
  width: 300px;
  position: fixed;
  background-color: #111;
}

#navbar h1 {
  font-size: 2.2rem;
  text-align: center;
  color: rgb(160, 0, 0);
  font-weight: 400;
}

#navbar ul {
  padding-left: 2rem;
}

#navbar ul li {
  list-style: none;
}

#navbar .nav-link {
  text-decoration: none;
  display: block;
  color: #fff;
  font-size: 1.2rem;
  font-weight: 100;
  padding: 1rem 0;
}

#navbar .nav-link:hover,
#navbar .active {
  animation-name: hover-effect;
  animation-duration: 400ms;
  animation-fill-mode: forwards;
}

@keyframes hover-effect {
  100% {
    color: rgb(160, 0, 0);
    border-bottom: 1px solid rgb(133, 70, 70);
    padding-left: 0.5rem;
  }
}

/* Main */
#main-doc {
  padding-right: 3rem;
  margin-left: 350px;
  margin-bottom: 32rem;
}

.main-section {
  margin-bottom: 4rem;
}

#Introduction p {
  padding-left: 1rem;
}

code.editor,
code.console {
  display: block;
  background: #f4f4f4;
  padding: 1.2rem 1.1rem;
  margin: 1rem 0;
  margin-left: 1rem;
  border-radius: 5px;
  font-size: 1.1rem;
  line-height: 1.9;
  overflow: auto;
  white-space: nowrap;
}

code.console {
  background: rgb(0, 0, 0);
  color: rgb(79, 191, 64);
}

code.incorrect {
  background: rgba(255, 0, 0, 0.1);
}

code .comment {
  color: green;
}

code#str-comment {
  color: #aa0000;
  line-height: inherit;
}

/* Media Queries */
/* (max-width:841px) */
@media (max-width: 841px) {
  /* Navbar */
  #navbar {
    position: static;
    min-width: 100%;
    height: 350px;
    overflow-y: scroll;
  }

  /* Main */
  #main-doc {
    margin: 0 1rem;
  }
}

/* (max-width:551px) */
@media (max-width: 551px) {
  h2 {
    padding-left: 0.3rem;
  }

  #main-doc {
    margin: 0;
    padding-right: 0.8rem;
  }

  code.editor,
  code.console {
    margin-left: 0;
  }
}

              
            
!

JS

              
                let mainNavLinks = document.querySelectorAll(".nav-link");

window.addEventListener("scroll", (event) => {
  let fromTop = window.scrollY;
  //while scrolling make the nav-list item <a> state active if in that specific region.
  mainNavLinks.forEach((link) => {
    let section = document.querySelector(link.hash);
    if (
      section.offsetTop <= fromTop &&
      section.offsetTop + section.offsetHeight >fromTop
    ) {
      link.classList.add("active");
    } else {
      link.classList.remove("active");
    }
  });
});

              
            
!
999px

Console