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<div class="refnamediv">
<h1 class="refname">ereg_replace</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">ereg_replace</span> — <span class="dc-title">Replace regular expression</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.ereg-replace-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>ereg_replace</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$pattern</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$replacement</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$string</code></span>
)</div>
<p class="simpara">
This function scans <em><code class="parameter">string</code></em> for matches to
<em><code class="parameter">pattern</code></em>, then replaces the matched text
with <em><code class="parameter">replacement</code></em>.
</p>
<div class="warning"><strong class="warning">Warning</strong><p class="simpara">This function has been
<em class="emphasis">DEPRECATED</em> as of PHP 5.3.0. Relying on this feature is
highly discouraged.</p></div>
</div>
<div class="refsect1 parameters" id="refsect1-function.ereg-replace-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">pattern</code></em></span>
<dd>
<p class="para">
A POSIX extended regular expression.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">replacement</code></em></span>
<dd>
<p class="para">
If <em><code class="parameter">pattern</code></em> contains parenthesized substrings,
<em><code class="parameter">replacement</code></em> may contain substrings of the form
<em>\<span class="replaceable">digit</span></em>, which will be
replaced by the text matching the digit'th parenthesized substring;
<em>\0</em> will produce the entire contents of string.
Up to nine substrings may be used. Parentheses may be nested, in which
case they are counted by the opening parenthesis.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">string</code></em></span>
<dd>
<p class="para">
The input string.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.ereg-replace-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
The modified string is returned. If no matches are found in
<em><code class="parameter">string</code></em>, then it will be returned unchanged.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.ereg-replace-examples">
<h3 class="title">Examples</h3>
<p class="para">
For example, the following code snippet prints "This was a test"
three times:
</p>
<p class="para">
<div class="example" id="example-4806">
<p><strong>Example #1 <span class="function"><strong>ereg_replace()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$string </span><span style="color: #007700">= </span><span style="color: #DD0000">"This is a test"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">str_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">" is"</span><span style="color: #007700">, </span><span style="color: #DD0000">" was"</span><span style="color: #007700">, </span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">ereg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">"( )is"</span><span style="color: #007700">, </span><span style="color: #DD0000">"\\1was"</span><span style="color: #007700">, </span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">ereg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">"(( )is)"</span><span style="color: #007700">, </span><span style="color: #DD0000">"\\2was"</span><span style="color: #007700">, </span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
One thing to take note of is that if you use an integer value as
the <em><code class="parameter">replacement</code></em> parameter, you may not get
the results you expect. This is because
<span class="function"><strong>ereg_replace()</strong></span> will interpret the number as
the ordinal value of a character, and apply that. For instance:
</p>
<p class="para">
<div class="example" id="example-4807">
<p><strong>Example #2 <span class="function"><strong>ereg_replace()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/* This will not work as expected. */<br /></span><span style="color: #0000BB">$num </span><span style="color: #007700">= </span><span style="color: #0000BB">4</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$string </span><span style="color: #007700">= </span><span style="color: #DD0000">"This string has four words."</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$string </span><span style="color: #007700">= </span><span style="color: #0000BB">ereg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">'four'</span><span style="color: #007700">, </span><span style="color: #0000BB">$num</span><span style="color: #007700">, </span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">$string</span><span style="color: #007700">; </span><span style="color: #FF8000">/* Output: 'This string has words.' */<br /><br />/* This will work. */<br /></span><span style="color: #0000BB">$num </span><span style="color: #007700">= </span><span style="color: #DD0000">'4'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$string </span><span style="color: #007700">= </span><span style="color: #DD0000">"This string has four words."</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$string </span><span style="color: #007700">= </span><span style="color: #0000BB">ereg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">'four'</span><span style="color: #007700">, </span><span style="color: #0000BB">$num</span><span style="color: #007700">, </span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">$string</span><span style="color: #007700">; </span><span style="color: #FF8000">/* Output: 'This string has 4 words.' */<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
<div class="example" id="example-4808">
<p><strong>Example #3 Replace URLs with links</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$text </span><span style="color: #007700">= </span><span style="color: #0000BB">ereg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">"[[:alpha:]]+://[^<>[:space:]]+[[:alnum:]/]"</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'<a href="\\0">\\0</a>'</span><span style="color: #007700">, </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 notes" id="refsect1-function.ereg-replace-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <p class="para">As of PHP 5.3.0, the
regex extension is deprecated in favor of the
<a href="book.pcre.html" class="link">PCRE extension</a>. Calling this function
will issue an <strong><code>E_DEPRECATED</code></strong> notice. See <a href="reference.pcre.pattern.posix.html" class="link">the list of
differences</a> for help on converting to PCRE.</p></p></blockquote>
<div class="tip"><strong class="tip">Tip</strong>
<p class="para">
<span class="function"><strong>ereg_replace()</strong></span> is deprecated as of PHP 5.3.0. <span class="function"><a href="function.preg-replace.html" class="function">preg_replace()</a></span>
is the suggested alternative to this function.
</p>
</div>
</div>
<div class="refsect1 seealso" id="refsect1-function.ereg-replace-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.ereg.html" class="function" rel="rdfs-seeAlso">ereg()</a> - Regular expression match</span></li>
<li class="member"> <span class="function"><a href="function.eregi.html" class="function" rel="rdfs-seeAlso">eregi()</a> - Case insensitive regular expression match</span></li>
<li class="member"> <span class="function"><a href="function.eregi-replace.html" class="function" rel="rdfs-seeAlso">eregi_replace()</a> - Replace regular expression case insensitive</span></li>
<li class="member"> <span class="function"><a href="function.str-replace.html" class="function" rel="rdfs-seeAlso">str_replace()</a> - Replace all occurrences of the search string with the replacement string</span></li>
<li class="member"> <span class="function"><a href="function.preg-replace.html" class="function" rel="rdfs-seeAlso">preg_replace()</a> - Perform a regular expression search and replace</span></li>
<li class="member"> <span class="function"><a href="function.quotemeta.html" class="function" rel="rdfs-seeAlso">quotemeta()</a> - Quote meta characters</span></li>
</ul>
</p>
</div>
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