function.usort.html

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     </tbody>
    </colgroup>

   </table>
  </p>
 </div>

 <div class="refsect1 examples">
  <h3 class="title">Examples</h3>
  <p class="para">
   <div class="example">
    <p><b>Example #1 <b>usort()</b> example</b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">cmp</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">)<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">==&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;(</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">&lt;&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">)&nbsp;?&nbsp;-</span><span style="color: #0000BB">1&nbsp;</span><span style="color: #007700">:&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #0000BB">3</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">5</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">6</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">usort</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cmp"</span><span style="color: #007700">);<br /><br />foreach&nbsp;(</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">as&nbsp;</span><span style="color: #0000BB">$key&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">$value</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"$key:&nbsp;$value\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
0: 1
1: 2
2: 3
3: 5
4: 6
</pre></div>
    </pre></div>
   </div>
  </p>
  <blockquote><p><b class="note">Note</b>: 
   
    Obviously in this trivial case the <a href="function.sort.html" class="function">sort()</a>
    function would be more appropriate.
   <br />
  </p></blockquote>
  <p class="para">
   <div class="example">
    <p><b>Example #2 
     <b>usort()</b> example using multi-dimensional array
    </b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">cmp</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">)<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">strcmp</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">[</span><span style="color: #DD0000">"fruit"</span><span style="color: #007700">],&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">[</span><span style="color: #DD0000">"fruit"</span><span style="color: #007700">]);<br />}<br /><br /></span><span style="color: #0000BB">$fruits</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">][</span><span style="color: #DD0000">"fruit"</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">"lemons"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$fruits</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">][</span><span style="color: #DD0000">"fruit"</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">"apples"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$fruits</span><span style="color: #007700">[</span><span style="color: #0000BB">2</span><span style="color: #007700">][</span><span style="color: #DD0000">"fruit"</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">"grapes"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">usort</span><span style="color: #007700">(</span><span style="color: #0000BB">$fruits</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cmp"</span><span style="color: #007700">);<br /><br />while&nbsp;(list(</span><span style="color: #0000BB">$key</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$value</span><span style="color: #007700">)&nbsp;=&nbsp;</span><span style="color: #0000BB">each</span><span style="color: #007700">(</span><span style="color: #0000BB">$fruits</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"\$fruits[$key]:&nbsp;"&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">$value</span><span style="color: #007700">[</span><span style="color: #DD0000">"fruit"</span><span style="color: #007700">]&nbsp;.&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>
     When sorting a multi-dimensional array, <var class="varname">$a</var> and
    <var class="varname">$b</var> contain references to the first index of the array.
    </p></div>
    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
$fruits[0]: apples
$fruits[1]: grapes
$fruits[2]: lemons
</pre></div>
    </pre></div>
   </div>
  </p>
  <p class="para">
   <div class="example">
    <p><b>Example #3 
     <b>usort()</b> example using a member function of an object
    </b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">class&nbsp;</span><span style="color: #0000BB">TestObj&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;&nbsp;var&nbsp;</span><span style="color: #0000BB">$name</span><span style="color: #007700">;<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;function&nbsp;</span><span style="color: #0000BB">TestObj</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">)<br />&nbsp;&nbsp;&nbsp;&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">name&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$name</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/*&nbsp;This&nbsp;is&nbsp;the&nbsp;static&nbsp;comparing&nbsp;function:&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">static&nbsp;function&nbsp;</span><span style="color: #0000BB">cmp_obj</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">)<br />&nbsp;&nbsp;&nbsp;&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$al&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">strtolower</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">name</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$bl&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">strtolower</span><span style="color: #007700">(</span><span style="color: #0000BB">$b</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">name</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">$al&nbsp;</span><span style="color: #007700">==&nbsp;</span><span style="color: #0000BB">$bl</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;(</span><span style="color: #0000BB">$al&nbsp;</span><span style="color: #007700">&gt;&nbsp;</span><span style="color: #0000BB">$bl</span><span style="color: #007700">)&nbsp;?&nbsp;+</span><span style="color: #0000BB">1&nbsp;</span><span style="color: #007700">:&nbsp;-</span><span style="color: #0000BB">1</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />}<br /><br /></span><span style="color: #0000BB">$a</span><span style="color: #007700">[]&nbsp;=&nbsp;new&nbsp;</span><span style="color: #0000BB">TestObj</span><span style="color: #007700">(</span><span style="color: #DD0000">"c"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$a</span><span style="color: #007700">[]&nbsp;=&nbsp;new&nbsp;</span><span style="color: #0000BB">TestObj</span><span style="color: #007700">(</span><span style="color: #DD0000">"b"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$a</span><span style="color: #007700">[]&nbsp;=&nbsp;new&nbsp;</span><span style="color: #0000BB">TestObj</span><span style="color: #007700">(</span><span style="color: #DD0000">"d"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">usort</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;array(</span><span style="color: #DD0000">"TestObj"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cmp_obj"</span><span style="color: #007700">));<br /><br />foreach&nbsp;(</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">as&nbsp;</span><span style="color: #0000BB">$item</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #0000BB">$item</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">name&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
b
c
d
</pre></div>
    </pre></div>
   </div>
  </p>
 </div>

 <div class="refsect1 seealso">
  <h3 class="title">See Also</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><a href="function.uasort.html" class="function" rel="rdfs-seeAlso">uasort()</a></li>
    <li class="member"><a href="function.uksort.html" class="function" rel="rdfs-seeAlso">uksort()</a></li>
    <li class="member"><a href="function.sort.html" class="function" rel="rdfs-seeAlso">sort()</a></li>
    <li class="member"><a href="function.asort.html" class="function" rel="rdfs-seeAlso">asort()</a></li>
    <li class="member"><a href="function.arsort.html" class="function" rel="rdfs-seeAlso">arsort()</a></li>
    <li class="member"><a href="function.ksort.html" class="function" rel="rdfs-seeAlso">ksort()</a></li>
    <li class="member"><a href="function.natsort.html" class="function" rel="rdfs-seeAlso">natsort()</a></li>
    <li class="member"><a href="function.rsort.html" class="function" rel="rdfs-seeAlso">rsort()</a></li>
   </ul>
  </p>
 </div>

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