<h1>Converting UTF-8 characters to ISO-8859-1 and vice versa in PHP</h1>
<p>In today's digital world, it is essential to have a good understanding of character encoding. With the widespread use of different languages and alphabets, it is crucial to ensure that data is stored and transmitted correctly across various systems and platforms. One of the most common character encodings used is UTF-8, which can represent almost all characters and symbols in the world. However, there are instances where we may need to convert UTF-8 characters to another encoding, such as ISO-8859-1. In this article, we will explore how to convert UTF-8 characters to ISO-8859-1 and vice versa in PHP.</p>
<h2>Understanding UTF-8 and ISO-8859-1</h2>
<p>UTF-8 (Unicode Transformation Format 8-bit) is a variable-length encoding that uses 1 to 4 bytes to represent a character. It can represent over a million characters and is the most widely used encoding on the internet. ISO-8859-1 (Latin-1) is a single-byte encoding that can represent 256 characters and is commonly used in Western European languages.</p>
<p>So why do we need to convert between these two encodings? One of the main reasons is compatibility. Many older systems and applications may only support ISO-8859-1, and converting UTF-8 characters to ISO-8859-1 allows for proper data transmission and display. Additionally, some databases may only support one encoding, so converting data to the required format is necessary.</p>
<h2>Converting UTF-8 to ISO-8859-1</h2>
<p>To convert UTF-8 characters to ISO-8859-1, we can use the <code>mb_convert_encoding()</code> function in PHP, which stands for "multi-byte convert encoding." This function takes in three parameters: the string to be converted, the target encoding (in this case, ISO-8859-1), and the source encoding (UTF-8).</p>
<p>Let's take a look at an example:</p>
<code>$utf8_string = "Héllo, wörld!"; <br>
$iso_string = mb_convert_encoding($utf8_string, "ISO-8859-1", "UTF-8"); <br>
echo $iso_string; // Output: Héllo, wörld!</code>
<p>In the above example, we have a string with UTF-8 encoded characters. We use the <code>mb_convert_encoding()</code> function to convert it to ISO-8859-1 and store the result in a new variable. Finally, we can output the converted string, which should display correctly with the special characters preserved.</p>
<h2>Converting ISO-8859-1 to UTF-8</h2>
<p>The process of converting ISO-8859-1 characters to UTF-8 is similar to the previous example. We use the same <code>mb_convert_encoding()</code> function but with the target and source encoding parameters switched.</p>
