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<title>Find the position of the first occurrence of a substring in a string</title>
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<div class="refnamediv">
<h1 class="refname">strpos</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">strpos</span> — <span class="dc-title">Find the position of the first occurrence of a substring in a string</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.strpos-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">int</span> <span class="methodname"><strong>strpos</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$haystack</code></span>
, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$needle</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$offset</code><span class="initializer"> = 0</span></span>
] )</div>
<p class="para rdfs-comment">
Find the numeric position of the first occurrence of
<code class="parameter">needle</code> in the <code class="parameter">haystack</code> string.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.strpos-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">haystack</code></dt>
<dd>
<p class="para">
The string to search in.
</p>
</dd>
<dt>
<code class="parameter">needle</code></dt>
<dd>
<p class="para">
If <code class="parameter">needle</code> is not a string, it is converted
to an integer and applied as the ordinal value of a character.
</p>
</dd>
<dt>
<code class="parameter">offset</code></dt>
<dd>
<p class="para">
If specified, search will start this number of characters counted from
the beginning of the string. If the offset is negative, the search will start
this number of characters counted from the end of the string.
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.strpos-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the position of where the needle exists relative to the beginning of
the <code class="parameter">haystack</code> string (independent of offset).
Also note that string positions start at 0, and not 1.
</p>
<p class="para">
Returns <strong><code>FALSE</code></strong> if the needle was not found.
</p>
<div class="warning"><strong class="warning">Warning</strong><p class="simpara">This function may
return Boolean <strong><code>FALSE</code></strong>, but may also return a non-Boolean value which
evaluates to <strong><code>FALSE</code></strong>. Please read the section on <a href="language.types.boolean.html" class="link">Booleans</a> for more
information. Use <a href="language.operators.comparison.html" class="link">the ===
operator</a> for testing the return value of this
function.</p></div>
</div>
<div class="refsect1 changelog" id="refsect1-function.strpos-changelog">
<h3 class="title">Changelog</h3>
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>7.1.0</td>
<td>
Support for negative <code class="parameter">offset</code>s has been added.
</td>
</tr>
</tbody>
</table>
</div>
<div class="refsect1 examples" id="refsect1-function.strpos-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-6104">
<p><strong>Example #1 Using <em>===</em></strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$mystring </span><span style="color: #007700">= </span><span style="color: #DD0000">'abc'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$findme </span><span style="color: #007700">= </span><span style="color: #DD0000">'a'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$pos </span><span style="color: #007700">= </span><span style="color: #0000BB">strpos</span><span style="color: #007700">(</span><span style="color: #0000BB">$mystring</span><span style="color: #007700">, </span><span style="color: #0000BB">$findme</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Note our use of ===. Simply == would not work as expected<br />// because the position of 'a' was the 0th (first) character.<br /></span><span style="color: #007700">if (</span><span style="color: #0000BB">$pos </span><span style="color: #007700">=== </span><span style="color: #0000BB">false</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"The string '</span><span style="color: #0000BB">$findme</span><span style="color: #DD0000">' was not found in the string '</span><span style="color: #0000BB">$mystring</span><span style="color: #DD0000">'"</span><span style="color: #007700">;<br />} else {<br /> echo </span><span style="color: #DD0000">"The string '</span><span style="color: #0000BB">$findme</span><span style="color: #DD0000">' was found in the string '</span><span style="color: #0000BB">$mystring</span><span style="color: #DD0000">'"</span><span style="color: #007700">;<br /> echo </span><span style="color: #DD0000">" and exists at position </span><span style="color: #0000BB">$pos</span><span style="color: #DD0000">"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-6105">
<p><strong>Example #2 Using !==</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$mystring </span><span style="color: #007700">= </span><span style="color: #DD0000">'abc'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$findme </span><span style="color: #007700">= </span><span style="color: #DD0000">'a'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$pos </span><span style="color: #007700">= </span><span style="color: #0000BB">strpos</span><span style="color: #007700">(</span><span style="color: #0000BB">$mystring</span><span style="color: #007700">, </span><span style="color: #0000BB">$findme</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// The !== operator can also be used. Using != would not work as expected<br />// because the position of 'a' is 0. The statement (0 != false) evaluates <br />// to false.<br /></span><span style="color: #007700">if (</span><span style="color: #0000BB">$pos </span><span style="color: #007700">!== </span><span style="color: #0000BB">false</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"The string '</span><span style="color: #0000BB">$findme</span><span style="color: #DD0000">' was found in the string '</span><span style="color: #0000BB">$mystring</span><span style="color: #DD0000">'"</span><span style="color: #007700">;<br /> echo </span><span style="color: #DD0000">" and exists at position </span><span style="color: #0000BB">$pos</span><span style="color: #DD0000">"</span><span style="color: #007700">;<br />} else {<br /> echo </span><span style="color: #DD0000">"The string '</span><span style="color: #0000BB">$findme</span><span style="color: #DD0000">' was not found in the string '</span><span style="color: #0000BB">$mystring</span><span style="color: #DD0000">'"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-6106">
<p><strong>Example #3 Using an offset</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// We can search for the character, ignoring anything before the offset<br /></span><span style="color: #0000BB">$newstring </span><span style="color: #007700">= </span><span style="color: #DD0000">'abcdef abcdef'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$pos </span><span style="color: #007700">= </span><span style="color: #0000BB">strpos</span><span style="color: #007700">(</span><span style="color: #0000BB">$newstring</span><span style="color: #007700">, </span><span style="color: #DD0000">'a'</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">); </span><span style="color: #FF8000">// $pos = 7, not 0<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.strpos-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">This function is
binary-safe.</span></p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.strpos-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.stripos.html" class="function" rel="rdfs-seeAlso">stripos()</a> - Find the position of the first occurrence of a case-insensitive substring in a string</span></li>
<li class="member"><span class="function"><a href="function.strrpos.html" class="function" rel="rdfs-seeAlso">strrpos()</a> - Find the position of the last occurrence of a substring in a string</span></li>
<li class="member"><span class="function"><a href="function.strripos.html" class="function" rel="rdfs-seeAlso">strripos()</a> - Find the position of the last occurrence of a case-insensitive substring in a string</span></li>
<li class="member"><span class="function"><a href="function.strstr.html" class="function" rel="rdfs-seeAlso">strstr()</a> - Find the first occurrence of a string</span></li>
<li class="member"><span class="function"><a href="function.strpbrk.html" class="function" rel="rdfs-seeAlso">strpbrk()</a> - Search a string for any of a set of characters</span></li>
<li class="member"><span class="function"><a href="function.substr.html" class="function" rel="rdfs-seeAlso">substr()</a> - Return part of a string</span></li>
<li class="member"><span class="function"><a href="function.preg-match.html" class="function" rel="rdfs-seeAlso">preg_match()</a> - Perform a regular expression match</span></li>
</ul>
</p>
</div>
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