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English
In PHP, strings can use different character encoding formats. The two most common are ISO-8859-1 (also known as Latin1) and UTF-8. ISO-8859-1 is a single-byte encoding mainly used for Western European characters, while UTF-8 is a multi-byte encoding capable of representing almost all characters.
When reading data from external sources such as databases, APIs, or files, the encoding format of this data may not match the encoding used internally by your application. In such cases, converting the encoding is necessary to ensure proper display and processing.
The utf8_encode() function converts a string encoded in ISO-8859-1 into UTF-8. If your data source uses ISO-8859-1 while PHP internally processes strings as UTF-8, you need to use this function to perform the conversion.
<span><span><span class="hljs-variable">$isoString</span></span><span> = </span><span><span class="hljs-string">"Café"</span></span><span>; </span><span><span class="hljs-comment">// Assume this string is ISO-8859-1 encoded</span></span><span>
</span><span><span class="hljs-variable">$utf8String</span></span><span> = </span><span><span class="hljs-title function_ invoke__">utf8_encode</span></span><span>(</span><span><span class="hljs-variable">$isoString</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-variable">$utf8String</span></span><span>; </span><span><span class="hljs-comment">// Output: Café</span></span><span>
</span></span>To determine whether utf8_encode() is necessary, consider the following factors:
Encoding of the Data Source: If your data is in ISO-8859-1 (or any non-UTF-8 encoding) and you need to process or output it as UTF-8, you should use utf8_encode() to convert it.
Default Character Set of the Environment: Most modern PHP environments already use UTF-8 as the default character set. If your environment is UTF-8, you need to convert external data based on its actual encoding to prevent garbled text.
Encoding Expected by Browsers or Terminals: If your application outputs data to a browser, the browser typically expects UTF-8 encoding. If the data encoding does not match the browser’s expected charset, display issues may occur. In such cases, you can use utf8_encode() to convert the data to the correct charset.
Suppose you retrieve a field from a database that is ISO-8859-1 encoded, and you need to display it on a webpage. To avoid garbled characters, you usually need to convert it using utf8_encode().
<span><span><span class="hljs-comment">// ISO-8859-1 encoded data retrieved from the database</span></span><span>
</span><span><span class="hljs-variable">$dbString</span></span><span> = </span><span><span class="hljs-string">"El Ni?o"</span></span><span>; </span><span><span class="hljs-comment">// Assume the string retrieved from the database is ISO-8859-1</span></span><span>
<p></span>// Convert to UTF-8<br>
$utf8String = utf8_encode($dbString);</p>
<p>// Output to browser<br>
echo $utf8String; // Output: El Ni?o<br>
</span>If you are certain the data is already UTF-8 encoded, there is no need to call utf8_encode(), as unnecessary conversions may cause issues.
Sometimes you may be unsure of a string’s encoding. You can use the mb_detect_encoding() function to detect it and decide whether conversion is necessary.
<span><span><span class="hljs-variable">$string</span></span><span> = </span><span><span class="hljs-string">"El Ni?o"</span></span><span>; </span><span><span class="hljs-comment">// Assume the string’s encoding is unknown</span></span><span>
<p></span>// Detect the string’s encoding<br>
$encoding = mb_detect_encoding($string, </span>"ISO-8859-1, UTF-8");</p>
<p>if ($encoding == "ISO-8859-1") {<br>
// Convert to UTF-8 if it’s ISO-8859-1<br>
$string = utf8_encode($string);<br>
}</p>
<p>echo $string; // Output the converted string<br>
</span>Whenever possible, use UTF-8 encoding during application development. UTF-8 supports nearly all languages worldwide, avoiding encoding inconsistencies. If you are using a MySQL database, it is recommended to set the database and table character sets to UTF-8.
<span><span><span class="hljs-keyword">CREATE</span></span><span> DATABASE my_database </span><span><span class="hljs-type">CHARACTER</span></span><span> </span><span><span class="hljs-keyword">SET</span></span><span> utf8mb4 </span><span><span class="hljs-keyword">COLLATE</span></span><span> utf8mb4_unicode_ci;
</span></span>This approach helps reduce encoding conversion issues in later stages of development.
