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</div><hr /><div id="function.strtr" class="refentry">
<div class="refnamediv">
<h1 class="refname">strtr</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">strtr</span> — <span class="dc-title">Translate characters or replace substrings</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.strtr-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>strtr</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$str</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$from</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$to</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>strtr</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$str</code></span>
, <span class="methodparam"><span class="type">array</span> <code class="parameter">$replace_pairs</code></span>
)</div>
<p class="para rdfs-comment">
If given three arguments, this function returns a copy of
<em><code class="parameter">str</code></em> where all occurrences of each (single-byte)
character in <em><code class="parameter">from</code></em> have been translated to the
corresponding character in <em><code class="parameter">to</code></em>, i.e., every
occurrence of <em>$from[$n]</em> has been replaced with
<em>$to[$n]</em>, where <em>$n</em> is a valid
offset in both arguments.
</p>
<p class="para">
If <em><code class="parameter">from</code></em> and <em><code class="parameter">to</code></em> have
different lengths, the extra characters in the longer of the two
are ignored. The length of <em><code class="parameter">str</code></em> will be the same as
the return value's.
</p>
<p class="para">
If given two arguments, the second should be an <span class="type"><a href="language.types.array.html" class="type array">array</a></span> in the
form <em>array('from' => 'to', ...)</em>. The return value is
a <span class="type"><a href="language.types.string.html" class="type string">string</a></span> where all the occurrences of the array keys have been
replaced by the corresponding values. The longest keys will be tried first.
Once a substring has been replaced, its new value will not be searched
again.
</p>
<p class="para">
In this case, the keys and the values may have any length, provided that
there is no empty key; additionally, the length of the return value may
differ from that of <em><code class="parameter">str</code></em>.
However, this function will be the most efficient when all the keys have the
same size.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.strtr-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">str</code></em></span>
<dd>
<p class="para">
The <span class="type"><a href="language.types.string.html" class="type string">string</a></span> being translated.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">from</code></em></span>
<dd>
<p class="para">
The <span class="type"><a href="language.types.string.html" class="type string">string</a></span> being translated to <em><code class="parameter">to</code></em>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">to</code></em></span>
<dd>
<p class="para">
The <span class="type"><a href="language.types.string.html" class="type string">string</a></span> replacing <em><code class="parameter">from</code></em>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">replace_pairs</code></em></span>
<dd>
<p class="para">
The <em><code class="parameter">replace_pairs</code></em> parameter may be used instead of
<em><code class="parameter">to</code></em> and <em><code class="parameter">from</code></em>, in which case it's an
<span class="type"><a href="language.types.array.html" class="type array">array</a></span> in the form <em>array('from' => 'to', ...)</em>.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.strtr-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the translated <span class="type"><a href="language.types.string.html" class="type string">string</a></span>.
</p>
<p class="para">
If <em><code class="parameter">replace_pairs</code></em> contains a key which
is an empty <span class="type"><a href="language.types.string.html" class="type string">string</a></span> (<em>""</em>),
<strong><code>FALSE</code></strong> will be returned. If the <em><code class="parameter">str</code></em> is not a scalar
then it is not typecasted into a string, instead a warning is raised and
<strong><code>NULL</code></strong> is returned.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.strtr-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-4910">
<p><strong>Example #1 <span class="function"><strong>strtr()</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">//In this form, strtr() does byte-by-byte translation<br />//Therefore, we are assuming a single-byte encoding here:<br /></span><span style="color: #0000BB">$addr </span><span style="color: #007700">= </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #0000BB">$addr</span><span style="color: #007700">, </span><span style="color: #DD0000">"äåö"</span><span style="color: #007700">, </span><span style="color: #DD0000">"aao"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
The next example shows the behavior of <span class="function"><strong>strtr()</strong></span> when
called with only two arguments. Note the preference of the replacements
(<em>"h"</em> is not picked because there are longer matches)
and how replaced text was not searched again.
</p>
<div class="example" id="example-4911">
<p><strong>Example #2 <span class="function"><strong>strtr()</strong></span> example with two arguments</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$trans </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"h" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"-"</span><span style="color: #007700">, </span><span style="color: #DD0000">"hello" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"hi"</span><span style="color: #007700">, </span><span style="color: #DD0000">"hi" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"hello"</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #DD0000">"hi all, I said hello"</span><span style="color: #007700">, </span><span style="color: #0000BB">$trans</span><span style="color: #007700">);<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>
hello all, I said hi
</pre></div>
</div>
</div>
<p class="para">
The two modes of behavior are substantially different. With three arguments,
<span class="function"><strong>strtr()</strong></span> will replace bytes; with two, it may replace
longer substrings.
</p>
<div class="example" id="example-4912">
<p><strong>Example #3 <span class="function"><strong>strtr()</strong></span> behavior comparison</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #DD0000">"baab"</span><span style="color: #007700">, </span><span style="color: #DD0000">"ab"</span><span style="color: #007700">, </span><span style="color: #DD0000">"01"</span><span style="color: #007700">),</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$trans </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"ab" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"01"</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #DD0000">"baab"</span><span style="color: #007700">, </span><span style="color: #0000BB">$trans</span><span style="color: #007700">);<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>
1001
ba01
</pre></div>
</div>
</div>
</div>
<div class="refsect1 seealso" id="refsect1-function.strtr-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<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>
</ul>
</p>
</div>
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