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In PHP, string encoding conversion and cleanup are very common operations. When working with text in different encoding formats—especially in cross-platform applications or when dealing with external data sources—maintaining character accuracy and consistency can be a challenge. convert_cyr_string and str_replace are both very useful tools in PHP. Today, we’ll explore how they can be used together to achieve encoding cleanup and text normalization.
convert_cyr_string is a PHP function used for Cyrillic character encoding conversion. Cyrillic is an alphabet system used in many Eastern European languages. If you’re working with Russian or other text that uses the Cyrillic alphabet, convert_cyr_string can be particularly helpful.
The function prototype is:
<span><span><span class="hljs-title function_ invoke__">convert_cyr_string</span></span><span> ( </span><span><span class="hljs-keyword">string</span></span><span> </span><span><span class="hljs-variable">$str</span></span><span> , </span><span><span class="hljs-keyword">string</span></span><span> </span><span><span class="hljs-variable">$from</span></span><span> , </span><span><span class="hljs-keyword">string</span></span><span> </span><span><span class="hljs-variable">$to</span></span><span> ) : </span><span><span class="hljs-keyword">string</span></span><span>
</span></span>$str: The string to be converted.
$from: The source encoding, such as 'koi8-r' or 'win-1251'.
$to: The target encoding, such as 'koi8-r' or 'utf-8'.
For example, suppose we have a text encoded in KOI8-R. We can convert it to UTF-8 using convert_cyr_string:
<span><span><span class="hljs-variable">$text</span></span><span> = </span><span><span class="hljs-string">"Привет мир"</span></span><span>; </span><span><span class="hljs-comment">// KOI8-R encoding</span></span><span>
</span><span><span class="hljs-variable">$converted_text</span></span><span> = </span><span><span class="hljs-title function_ invoke__">convert_cyr_string</span></span><span>(</span><span><span class="hljs-variable">$text</span></span><span>, </span><span><span class="hljs-string">'koi8-r'</span></span><span>, </span><span><span class="hljs-string">'utf-8'</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-variable">$converted_text</span></span><span>; </span><span><span class="hljs-comment">// Output: Привет мир</span></span><span>
</span></span>Beyond encoding conversion, sometimes we need to clean up unnecessary characters from strings, such as special characters, newlines, or other unrecognized encodings. In these cases, str_replace can help replace or remove these characters.
The str_replace function is a PHP tool for replacing strings. Its prototype is:
<span><span><span class="hljs-title function_ invoke__">str_replace</span></span><span>( </span><span><span class="hljs-keyword">mixed</span></span><span> </span><span><span class="hljs-variable">$search</span></span><span> , </span><span><span class="hljs-keyword">mixed</span></span><span> </span><span><span class="hljs-variable">$replace</span></span><span> , </span><span><span class="hljs-keyword">mixed</span></span><span> </span><span><span class="hljs-variable">$subject</span></span><span> ) : </span><span><span class="hljs-keyword">mixed</span></span><span>
</span></span>$search: The character or string to search for.
$replace: The replacement character or string.
$subject: The original string where the replacement is applied.
For example, we can use str_replace to replace all newline characters with spaces, or to remove extra spaces:
<span><span><span class="hljs-variable">$text</span></span><span> = </span><span><span class="hljs-string">"Hello, \nWorld! \tThis is PHP."</span></span><span>;
</span><span><span class="hljs-variable">$cleaned_text</span></span><span> = </span><span><span class="hljs-title function_ invoke__">str_replace</span></span><span>(</span><span><span class="hljs-keyword">array</span></span><span>(</span><span><span class="hljs-string">"\n"</span></span><span>, </span><span><span class="hljs-string">"\t"</span></span><span>), </span><span><span class="hljs-string">' '</span></span><span>, </span><span><span class="hljs-variable">$text</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-variable">$cleaned_text</span></span><span>; </span><span><span class="hljs-comment">// Output: Hello, World! This is PHP.</span></span><span>
</span></span>When we need both encoding conversion and character cleanup, convert_cyr_string and str_replace work well together. Suppose you have text containing Cyrillic characters, but it also includes invalid characters like extra newlines or non-printable characters. We can first use convert_cyr_string for encoding conversion, then str_replace to remove unwanted characters.
For example, imagine you have text encoded in KOI8-R, with mixed-in newlines and extra spaces. Here’s how you can clean it up:
<span><span><span class="hljs-variable">$text</span></span><span> = </span><span><span class="hljs-string">"Привет \nмир! \tЭто \tтестовый \nтекст."</span></span><span>;
</span><span><span class="hljs-comment">// First, convert KOI8-R encoding to UTF-8</span></span><span>
</span><span><span class="hljs-variable">$converted_text</span></span><span> = </span><span><span class="hljs-title function_ invoke__">convert_cyr_string</span></span><span>(</span><span><span class="hljs-variable">$text</span></span><span>, </span><span><span class="hljs-string">'koi8-r'</span></span><span>, </span><span><span class="hljs-string">'utf-8'</span></span><span>);
</span><span><span class="hljs-comment">// Then, use str_replace to remove extra spaces and newlines</span></span><span>
</span><span><span class="hljs-variable">$cleaned_text</span></span><span> = </span><span><span class="hljs-title function_ invoke__">str_replace</span></span><span>(</span><span><span class="hljs-keyword">array</span></span><span>(</span><span><span class="hljs-string">"\n"</span></span><span>, </span><span><span class="hljs-string">"\t"</span></span><span>), </span><span><span class="hljs-string">' '</span></span><span>, </span><span><span class="hljs-variable">$converted_text</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-variable">$cleaned_text</span></span><span>; </span><span><span class="hljs-comment">// Output: Привет мир! Это тестовый текст.</span></span><span>
</span></span>By following this approach—first using convert_cyr_string to handle encoding issues, then str_replace to clean up unwanted characters—you’ll end up with clean, normalized text.
Although convert_cyr_string is not directly used for text cleanup, when combined with other functions like str_replace, it can effectively clean and normalize text, especially when dealing with different character encodings. This combination allows us to easily perform encoding conversion and character cleanup, ensuring text consistency across different systems or platforms.
We hope today’s introduction helps you better understand how to use convert_cyr_string and str_replace to handle text encoding and cleanup tasks!
