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<title>Prints human-readable information about a variable</title>
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</div><hr /><div id="function.print-r" class="refentry">
<div class="refnamediv">
<h1 class="refname">print_r</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">print_r</span> — <span class="dc-title">
Prints human-readable information about a variable
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.print-r-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>print_r</strong></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">$expression</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$return</code><span class="initializer"> = false</span></span>
] )</div>
<p class="para rdfs-comment">
<span class="function"><strong>print_r()</strong></span> displays information about a variable
in a way that's readable by humans.
</p>
<p class="para">
<span class="function"><strong>print_r()</strong></span>, <span class="function"><a href="function.var-dump.html" class="function">var_dump()</a></span> and
<span class="function"><a href="function.var-export.html" class="function">var_export()</a></span> will
also show protected and private properties of objects with PHP 5.
Static class members will not be shown.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.print-r-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">expression</code></em></span>
<dd>
<p class="para">
The expression to be printed.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">return</code></em></span>
<dd>
<p class="para">
If you would like to capture the output of <span class="function"><strong>print_r()</strong></span>,
use the <em><code class="parameter">return</code></em> parameter. When this parameter is set
to <strong><code>TRUE</code></strong>, <span class="function"><strong>print_r()</strong></span> will return the information rather than print it.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.print-r-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
If given a <span class="type"><a href="language.types.string.html" class="type string">string</a></span>, <span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span> or <span class="type"><a href="language.types.float.html" class="type float">float</a></span>,
the value itself will be printed. If given an <span class="type"><a href="language.types.array.html" class="type array">array</a></span>, values
will be presented in a format that shows keys and elements. Similar
notation is used for <span class="type"><a href="language.types.object.html" class="type object">object</a></span>s.
</p>
<p class="para">
When the <em><code class="parameter">return</code></em> parameter is <strong><code>TRUE</code></strong>, this function
will return a <span class="type"><a href="language.types.string.html" class="type string">string</a></span>. Otherwise, the return value is <strong><code>TRUE</code></strong>.
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.print-r-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <p class="para">When the <em><code class="parameter">return</code></em> parameter
is used, this function uses internal output buffering so it cannot be used inside an
<span class="function"><a href="function.ob-start.html" class="function">ob_start()</a></span> callback function.</p></p></blockquote>
</div>
<div class="refsect1 changelog" id="refsect1-function.print-r-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>4.3.0</td>
<td>
The <em><code class="parameter">return</code></em> parameter was added. If you need to
capture the output of <span class="function"><strong>print_r()</strong></span> with an older
version of PHP prior, use the
<a href="ref.outcontrol.html" class="link">output-control functions</a>.
</td>
</tr>
<tr>
<td>4.0.4</td>
<td>
Prior to PHP 4.0.4, <span class="function"><strong>print_r()</strong></span> will continue forever
if given an <span class="type"><a href="language.types.array.html" class="type array">array</a></span> or <span class="type"><a href="language.types.object.html" class="type object">object</a></span> that
contains a direct or indirect reference to itself. An example
is <em>print_r($GLOBALS)</em> because
<em>$GLOBALS</em> is itself a global variable that
contains a reference to itself.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.print-r-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-5269">
<p><strong>Example #1 <span class="function"><strong>print_r()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<pre><br /><span style="color: #0000BB"><?php<br />$a </span><span style="color: #007700">= array (</span><span style="color: #DD0000">'a' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'apple'</span><span style="color: #007700">, </span><span style="color: #DD0000">'b' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'banana'</span><span style="color: #007700">, </span><span style="color: #DD0000">'c' </span><span style="color: #007700">=> array (</span><span style="color: #DD0000">'x'</span><span style="color: #007700">, </span><span style="color: #DD0000">'y'</span><span style="color: #007700">, </span><span style="color: #DD0000">'z'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">print_r </span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?><br /></span></pre></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>
<pre>
Array
(
[a] => apple
[b] => banana
[c] => Array
(
[0] => x
[1] => y
[2] => z
)
)
</pre>
</pre></div>
</div>
</div>
</p>
<p class="para">
<div class="example" id="example-5270">
<p><strong>Example #2 <em><code class="parameter">return</code></em> parameter example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$b </span><span style="color: #007700">= array (</span><span style="color: #DD0000">'m' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'monkey'</span><span style="color: #007700">, </span><span style="color: #DD0000">'foo' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'bar'</span><span style="color: #007700">, </span><span style="color: #DD0000">'x' </span><span style="color: #007700">=> array (</span><span style="color: #DD0000">'x'</span><span style="color: #007700">, </span><span style="color: #DD0000">'y'</span><span style="color: #007700">, </span><span style="color: #DD0000">'z'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">$results </span><span style="color: #007700">= </span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$b</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">); </span><span style="color: #FF8000">// $results now contains output from print_r<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.print-r-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.ob-start.html" class="function" rel="rdfs-seeAlso">ob_start()</a> - Turn on output buffering</span></li>
<li class="member"> <span class="function"><a href="function.var-dump.html" class="function" rel="rdfs-seeAlso">var_dump()</a> - Dumps information about a variable</span></li>
<li class="member"> <span class="function"><a href="function.var-export.html" class="function" rel="rdfs-seeAlso">var_export()</a> - Outputs or returns a parsable string representation of a variable</span></li>
</ul>
</p>
</div>
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