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<title>Return information about characters used in a string</title>
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<div class="refnamediv">
<h1 class="refname">count_chars</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">count_chars</span> — <span class="dc-title">Return information about characters used in a string</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.count-chars-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>count_chars</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$string</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$mode</code><span class="initializer"> = 0</span></span>
] )</div>
<p class="para rdfs-comment">
Counts the number of occurrences of every byte-value (0..255) in
<em><code class="parameter">string</code></em> and returns it in various ways.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.count-chars-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">string</code></em></span>
<dd>
<p class="para">
The examined string.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">mode</code></em></span>
<dd>
<p class="para">
See return values.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.count-chars-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Depending on <em><code class="parameter">mode</code></em>
<span class="function"><strong>count_chars()</strong></span> returns one of the following:
<ul class="itemizedlist">
<li class="listitem">
<span class="simpara">
0 - an array with the byte-value as key and the frequency of
every byte as value.
</span>
</li>
<li class="listitem">
<span class="simpara">
1 - same as 0 but only byte-values with a frequency greater
than zero are listed.
</span>
</li>
<li class="listitem">
<span class="simpara">
2 - same as 0 but only byte-values with a frequency equal to
zero are listed.
</span>
</li>
<li class="listitem">
<span class="simpara">
3 - a string containing all unique characters is returned.
</span>
</li>
<li class="listitem">
<span class="simpara">
4 - a string containing all not used characters is returned.
</span>
</li>
</ul>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.count-chars-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-4822">
<p><strong>Example #1 <span class="function"><strong>count_chars()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$data </span><span style="color: #007700">= </span><span style="color: #DD0000">"Two Ts and one F."</span><span style="color: #007700">;<br /><br />foreach (</span><span style="color: #0000BB">count_chars</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">) as </span><span style="color: #0000BB">$i </span><span style="color: #007700">=> </span><span style="color: #0000BB">$val</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"There were </span><span style="color: #0000BB">$val</span><span style="color: #DD0000"> instance(s) of \"" </span><span style="color: #007700">, </span><span style="color: #0000BB">chr</span><span style="color: #007700">(</span><span style="color: #0000BB">$i</span><span style="color: #007700">) , </span><span style="color: #DD0000">"\" in the string.\n"</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>
There were 4 instance(s) of " " in the string.
There were 1 instance(s) of "." in the string.
There were 1 instance(s) of "F" in the string.
There were 2 instance(s) of "T" in the string.
There were 1 instance(s) of "a" in the string.
There were 1 instance(s) of "d" in the string.
There were 1 instance(s) of "e" in the string.
There were 2 instance(s) of "n" in the string.
There were 2 instance(s) of "o" in the string.
There were 1 instance(s) of "s" in the string.
There were 1 instance(s) of "w" in the string.
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.count-chars-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.strpos.html" class="function" rel="rdfs-seeAlso">strpos()</a> - Find the position of the first occurrence of a substring in a string</span></li>
<li class="member"> <span class="function"><a href="function.substr-count.html" class="function" rel="rdfs-seeAlso">substr_count()</a> - Count the number of substring occurrences</span></li>
</ul>
</p>
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