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<title>Perform a regular expresssion seach and replace with multibyte support using a callback</title>
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<h1 class="refname">mb_ereg_replace_callback</h1>
<p class="verinfo">(PHP 5 >= 5.4.1, PHP 7)</p><p class="refpurpose"><span class="refname">mb_ereg_replace_callback</span> — <span class="dc-title">Perform a regular expresssion seach and replace with multibyte support using a callback
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.mb-ereg-replace-callback-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>mb_ereg_replace_callback</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$pattern</code></span>
, <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$callback</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$string</code></span>
[, <span class="methodparam"><span class="type">string</span> <code class="parameter">$option</code><span class="initializer"> = "msr"</span></span>
] )</div>
<p class="para rdfs-comment">
Scans <code class="parameter">string</code> for matches to
<code class="parameter">pattern</code>, then replaces the matched text
with the output of <code class="parameter">callback</code> function.
</p>
<p class="para">
The behavior of this function is almost identical to <span class="function"><a href="function.mb-ereg-replace.html" class="function">mb_ereg_replace()</a></span>,
except for the fact that instead of
<code class="parameter">replacement</code> parameter, one should specify a
<code class="parameter">callback</code>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.mb-ereg-replace-callback-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">pattern</code></dt>
<dd>
<p class="para">
The regular expression pattern.
</p>
<p class="para">
Multibyte characters may be used in <code class="parameter">pattern</code>.
</p>
</dd>
<dt>
<code class="parameter">callback</code></dt>
<dd>
<p class="para">
A callback that will be called and passed an array of matched elements
in the <code class="parameter">subject</code> string. The callback should
return the replacement string.
</p>
<p class="para">
You'll often need the <code class="parameter">callback</code> function
for a <span class="function"><strong>mb_ereg_replace_callback()</strong></span> in just one place.
In this case you can use an
<a href="functions.anonymous.html" class="link">anonymous function</a> to
declare the callback within the call to
<span class="function"><strong>mb_ereg_replace_callback()</strong></span>. By doing it this way
you have all information for the call in one place and do not
clutter the function namespace with a callback function's name
not used anywhere else.
</p>
</dd>
<dt>
<code class="parameter">string</code></dt>
<dd>
<p class="para">
The <span class="type"><a href="language.types.string.html" class="type string">string</a></span> being checked.
</p>
</dd>
<dt>
<code class="parameter">option</code></dt>
<dd>
<p class="para">
The search option. See <span class="function"><a href="function.mb-regex-set-options.html" class="function">mb_regex_set_options()</a></span> for explanation.
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.mb-ereg-replace-callback-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
The resultant <span class="type"><a href="language.types.string.html" class="type string">string</a></span> on success, or <strong><code>FALSE</code></strong> on error.
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.mb-ereg-replace-callback-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <p class="para">The internal encoding or the
character encoding specified by <span class="function"><a href="function.mb-regex-encoding.html" class="function">mb_regex_encoding()</a></span>
will be used as the character encoding for this function.</p></p></blockquote>
</div>
<div class="refsect1 examples" id="refsect1-function.mb-ereg-replace-callback-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-3274">
<p><strong>Example #1 <span class="function"><strong>mb_ereg_replace_callback()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// this text was used in 2002<br />// we want to get this up to date for 2003<br /></span><span style="color: #0000BB">$text </span><span style="color: #007700">= </span><span style="color: #DD0000">"April fools day is 04/01/2002\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$text</span><span style="color: #007700">.= </span><span style="color: #DD0000">"Last christmas was 12/24/2001\n"</span><span style="color: #007700">;<br /></span><span style="color: #FF8000">// the callback function<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">next_year</span><span style="color: #007700">(</span><span style="color: #0000BB">$matches</span><span style="color: #007700">)<br />{<br /> </span><span style="color: #FF8000">// as usual: $matches[0] is the complete match<br /> // $matches[1] the match for the first subpattern<br /> // enclosed in '(...)' and so on<br /> </span><span style="color: #007700">return </span><span style="color: #0000BB">$matches</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">].(</span><span style="color: #0000BB">$matches</span><span style="color: #007700">[</span><span style="color: #0000BB">2</span><span style="color: #007700">]+</span><span style="color: #0000BB">1</span><span style="color: #007700">);<br />}<br />echo </span><span style="color: #0000BB">mb_ereg_replace_callback</span><span style="color: #007700">(<br /> </span><span style="color: #DD0000">"(\d{2}/\d{2}/)(\d{4})"</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">"next_year"</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">$text</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
April fools day is 04/01/2003
Last christmas was 12/24/2002
</pre></div>
</div>
</div>
</p>
<p class="para">
<div class="example" id="example-3275">
<p><strong>Example #2 <span class="function"><strong>mb_ereg_replace_callback()</strong></span> using anonymous function
supported in PHP 5.3.0 or later</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// this text was used in 2002<br />// we want to get this up to date for 2003<br /></span><span style="color: #0000BB">$text </span><span style="color: #007700">= </span><span style="color: #DD0000">"April fools day is 04/01/2002\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$text</span><span style="color: #007700">.= </span><span style="color: #DD0000">"Last christmas was 12/24/2001\n"</span><span style="color: #007700">;<br /><br />echo </span><span style="color: #0000BB">mb_ereg_replace_callback</span><span style="color: #007700">(<br /> </span><span style="color: #DD0000">"(\d{2}/\d{2}/)(\d{4})"</span><span style="color: #007700">,<br /> function (</span><span style="color: #0000BB">$matches</span><span style="color: #007700">) {<br /> return </span><span style="color: #0000BB">$matches</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">].(</span><span style="color: #0000BB">$matches</span><span style="color: #007700">[</span><span style="color: #0000BB">2</span><span style="color: #007700">]+</span><span style="color: #0000BB">1</span><span style="color: #007700">);<br /> },<br /> </span><span style="color: #0000BB">$text</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.mb-ereg-replace-callback-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.mb-regex-encoding.html" class="function" rel="rdfs-seeAlso">mb_regex_encoding()</a> - Set/Get character encoding for multibyte regex</span></li>
<li class="member"><span class="function"><a href="function.mb-ereg-replace.html" class="function" rel="rdfs-seeAlso">mb_ereg_replace()</a> - Replace regular expression with multibyte support</span></li>
<li class="member"><a href="functions.anonymous.html" class="link">Anonymous functions</a></li>
<li class="member">information about the <a href="language.pseudo-types.html#language.types.callback" class="link">callback</a> type</li>
</ul>
</p>
</div>
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