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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)</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"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></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
<em><code class="parameter">needle</code></em> in the <em><code class="parameter">haystack</code></em> string.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.strpos-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">haystack</code></em></span>
<dd>
<p class="para">
The string to search in.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">needle</code></em></span>
<dd>
<p class="para">
If <em><code class="parameter">needle</code></em> is not a string, it is converted
to an integer and applied as the ordinal value of a character.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">offset</code></em></span>
<dd>
<p class="para">
If specified, search will start this number of characters counted from
the beginning of the string. Unlike <span class="function"><a href="function.strrpos.html" class="function">strrpos()</a></span> and
<span class="function"><a href="function.strripos.html" class="function">strripos()</a></span>, the offset cannot be negative.
</p>
</dd>
</dt>
</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 <em><code class="parameter">haystack</code></em> 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 examples" id="refsect1-function.strpos-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-4895">
<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-4896">
<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">$mystring</span><span style="color: #DD0000">'"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-4897">
<p><strong>Example #3 Using an offset</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// We can search for the character, ignoring anything before the offset<br /></span><span style="color: #0000BB">$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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