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English
In PHP, when working with strings, we often need to remove specific parts from a string. The mb_strstr() function is a multibyte string function that is particularly useful for handling non-ASCII characters. This article will explain how to use mb_strstr() to remove a designated part from a string.
mb_strstr() is a multibyte string function similar to the standard strstr() function, but it is designed specifically for multibyte character sets (such as UTF-8, Shift-JIS, etc.). Therefore, when we need to work with strings containing non-English characters, mb_strstr() is more stable and reliable.
<span><span><span class="hljs-title function_ invoke__">mb_strstr</span></span><span>(</span><span><span class="hljs-keyword">string</span></span> <span>$haystack</span>, <span class="hljs-keyword">string</span> <span>$needle</span>, <span class="hljs-keyword">bool</span> <span>$before_needle</span> = <span class="hljs-literal">false</span>, <span class="hljs-keyword">string</span> <span>$encoding</span> = <span class="hljs-literal">null</span>): <span class="hljs-keyword">string</span>|<span class="hljs-literal">false</span>
$haystack: The target string to search within.
$needle: The substring to look for.
$before_needle (optional): If set to true, returns the part before needle; otherwise, returns needle and the part after it.
$encoding (optional): Specifies the character encoding, defaulting to mb_internal_encoding().
Suppose we have a string and want to remove a part of it. We can use mb_strstr() to locate that part and then remove it through string manipulation.
Suppose we have the following string:
<span>$str = "I love learning PHP programming"</span>
We want to remove the part "learning". We can first use mb_strstr() to find its position and then process accordingly.
<span><?php
$str = "I love learning PHP programming";
$needle = "learning";
<p>// Use mb_strstr to find the position of "learning"<br>
$position = mb_strstr($str, $needle);</p>
<p>// If "learning" is found, remove it<br>
if ($position !== false) {<br>
// Remove the "learning" part from the string<br>
$result = mb_substr($str, 0, mb_strpos($str, $needle)) . mb_substr($str, mb_strpos($str, $needle) + mb_strlen($needle));<br>
echo $result;<br>
} else {<br>
echo "Specified part not found";<br>
}<br>
?><br>
<span>I love PHP programming
If we only want to remove the part after a substring, we can use the before_needle parameter of mb_strstr().
<?php
$str = "I love learning PHP programming";
$needle = "learning";
<p>// Get the part before "learning"<br>
$before = mb_strstr($str, $needle, true);</p>
<p>echo $before;<br>
?><br>
<span>I love
If we need to remove multiple different substrings from a string, we can combine mb_strstr() with other string manipulation functions. This can be efficiently done using loops and regular expressions.
<?php
$str = "I love learning PHP programming and Web development";
$needles = ["learning", "Web"];
<p>// Remove multiple substrings<br>
foreach ($needles as $needle) {<br>
$str = str_replace($needle, "", $str);<br>
}</p>
<p>echo $str;<br>
?><br>
<span>I love PHP programming and development
mb_strstr() is optimized for multibyte character sets and generally performs better than the standard strstr() when handling Chinese, Japanese, Korean, and other multibyte characters.
When working with multibyte characters, ensure the correct encoding is specified; otherwise, the results may be inaccurate.
In some cases, combining mb_substr() and mb_strpos() allows precise control over which parts of a string are removed.
Using the mb_strstr() function, we can easily remove specific parts from a string, especially when working with multibyte character sets. Mastering these techniques not only improves efficiency in string manipulation but also helps avoid common encoding issues.
