function.xml-parse-into-struct.html

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Array
(
    [PARA] => Array
        (
            [0] => 0
            [1] => 2
        )

    [NOTE] => Array
        (
            [0] => 1
        )

)

Vals array
Array
(
    [0] => Array
        (
            [tag] => PARA
            [type] => open
            [level] => 1
        )

    [1] => Array
        (
            [tag] => NOTE
            [type] => complete
            [level] => 2
            [value] => simple note
        )

    [2] => Array
        (
            [tag] => PARA
            [type] => close
            [level] => 1
        )

)
</pre></div>
    </pre></div>
   </div>
  </p>
  <p class="para">
   Event-driven parsing (based on the expat library) can get
   complicated when you have an XML document that is complex.
   This function does not produce a DOM style object, but it
   generates structures amenable of being transversed in a tree
   fashion. Thus, we can create objects representing the data
   in the XML file easily. Let&#039;s consider the following XML file
   representing a small database of aminoacids information:
   <div class="example">
    <p><b>Example #2 moldb.xml - small database of molecular information</b></p>
    <div class="example-contents">
<div class="cdata"><pre>
&lt;?xml version=&quot;1.0&quot;?&gt;
&lt;moldb&gt;

  &lt;molecule&gt;
      &lt;name&gt;Alanine&lt;/name&gt;
      &lt;symbol&gt;ala&lt;/symbol&gt;
      &lt;code&gt;A&lt;/code&gt;
      &lt;type&gt;hydrophobic&lt;/type&gt;
  &lt;/molecule&gt;

  &lt;molecule&gt;
      &lt;name&gt;Lysine&lt;/name&gt;
      &lt;symbol&gt;lys&lt;/symbol&gt;
      &lt;code&gt;K&lt;/code&gt;
      &lt;type&gt;charged&lt;/type&gt;
  &lt;/molecule&gt;

&lt;/moldb&gt;
</pre></div>
    </div>

   </div>
   And some code to parse the document and generate the appropriate
   objects:
   <div class="example">
    <p><b>Example #3 
     parsemoldb.php - parses moldb.xml into an array of
     molecular objects
    </b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #007700">class&nbsp;</span><span style="color: #0000BB">AminoAcid&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;&nbsp;var&nbsp;</span><span style="color: #0000BB">$name</span><span style="color: #007700">;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;aa&nbsp;name<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">var&nbsp;</span><span style="color: #0000BB">$symbol</span><span style="color: #007700">;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;three&nbsp;letter&nbsp;symbol<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">var&nbsp;</span><span style="color: #0000BB">$code</span><span style="color: #007700">;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;one&nbsp;letter&nbsp;code<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">var&nbsp;</span><span style="color: #0000BB">$type</span><span style="color: #007700">;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;hydrophobic,&nbsp;charged&nbsp;or&nbsp;neutral<br />&nbsp;&nbsp;&nbsp;&nbsp;<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">AminoAcid&nbsp;</span><span style="color: #007700">(</span><span style="color: #0000BB">$aa</span><span style="color: #007700">)&nbsp;<br />&nbsp;&nbsp;&nbsp;&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;foreach&nbsp;(</span><span style="color: #0000BB">$aa&nbsp;</span><span style="color: #007700">as&nbsp;</span><span style="color: #0000BB">$k</span><span style="color: #007700">=&gt;</span><span style="color: #0000BB">$v</span><span style="color: #007700">)<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">$k&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$aa</span><span style="color: #007700">[</span><span style="color: #0000BB">$k</span><span style="color: #007700">];<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />}<br /><br />function&nbsp;</span><span style="color: #0000BB">readDatabase</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">)&nbsp;<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;read&nbsp;the&nbsp;XML&nbsp;database&nbsp;of&nbsp;aminoacids<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$data&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">""</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">file</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">));<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$parser&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">xml_parser_create</span><span style="color: #007700">();<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">xml_parser_set_option</span><span style="color: #007700">(</span><span style="color: #0000BB">$parser</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">XML_OPTION_CASE_FOLDING</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">xml_parser_set_option</span><span style="color: #007700">(</span><span style="color: #0000BB">$parser</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">XML_OPTION_SKIP_WHITE</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">xml_parse_into_struct</span><span style="color: #007700">(</span><span style="color: #0000BB">$parser</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$data</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$values</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$tags</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">xml_parser_free</span><span style="color: #007700">(</span><span style="color: #0000BB">$parser</span><span style="color: #007700">);<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;loop&nbsp;through&nbsp;the&nbsp;structures<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">foreach&nbsp;(</span><span style="color: #0000BB">$tags&nbsp;</span><span style="color: #007700">as&nbsp;</span><span style="color: #0000BB">$key</span><span style="color: #007700">=&gt;</span><span style="color: #0000BB">$val</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">$key&nbsp;</span><span style="color: #007700">==&nbsp;</span><span style="color: #DD0000">"molecule"</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$molranges&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$val</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;each&nbsp;contiguous&nbsp;pair&nbsp;of&nbsp;array&nbsp;entries&nbsp;are&nbsp;the&nbsp;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;lower&nbsp;and&nbsp;upper&nbsp;range&nbsp;for&nbsp;each&nbsp;molecule&nbsp;definition<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">for&nbsp;(</span><span style="color: #0000BB">$i</span><span style="color: #007700">=</span><span style="color: #0000BB">0</span><span style="color: #007700">;&nbsp;</span><span style="color: #0000BB">$i&nbsp;</span><span style="color: #007700">&lt;&nbsp;</span><span style="color: #0000BB">count</span><span style="color: #007700">(</span><span style="color: #0000BB">$molranges</span><span style="color: #007700">);&nbsp;</span><span style="color: #0000BB">$i</span><span style="color: #007700">+=</span><span style="color: #0000BB">2</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$offset&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$molranges</span><span style="color: #007700">[</span><span style="color: #0000BB">$i</span><span style="color: #007700">]&nbsp;+&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$len&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$molranges</span><span style="color: #007700">[</span><span style="color: #0000BB">$i&nbsp;</span><span style="color: #007700">+&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">]&nbsp;-&nbsp;</span><span style="color: #0000BB">$offset</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$tdb</span><span style="color: #007700">[]&nbsp;=&nbsp;</span><span style="color: #0000BB">parseMol</span><span style="color: #007700">(</span><span style="color: #0000BB">array_slice</span><span style="color: #007700">(</span><span style="color: #0000BB">$values</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$offset</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$len</span><span style="color: #007700">));<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}&nbsp;else&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;continue;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">$tdb</span><span style="color: #007700">;<br />}<br /><br />function&nbsp;</span><span style="color: #0000BB">parseMol</span><span style="color: #007700">(</span><span style="color: #0000BB">$mvalues</span><span style="color: #007700">)&nbsp;<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;(</span><span style="color: #0000BB">$i</span><span style="color: #007700">=</span><span style="color: #0000BB">0</span><span style="color: #007700">;&nbsp;</span><span style="color: #0000BB">$i&nbsp;</span><span style="color: #007700">&lt;&nbsp;</span><span style="color: #0000BB">count</span><span style="color: #007700">(</span><span style="color: #0000BB">$mvalues</span><span style="color: #007700">);&nbsp;</span><span style="color: #0000BB">$i</span><span style="color: #007700">++)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$mol</span><span style="color: #007700">[</span><span style="color: #0000BB">$mvalues</span><span style="color: #007700">[</span><span style="color: #0000BB">$i</span><span style="color: #007700">][</span><span style="color: #DD0000">"tag"</span><span style="color: #007700">]]&nbsp;=&nbsp;</span><span style="color: #0000BB">$mvalues</span><span style="color: #007700">[</span><span style="color: #0000BB">$i</span><span style="color: #007700">][</span><span style="color: #DD0000">"value"</span><span style="color: #007700">];<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;new&nbsp;</span><span style="color: #0000BB">AminoAcid</span><span style="color: #007700">(</span><span style="color: #0000BB">$mol</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">$db&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">readDatabase</span><span style="color: #007700">(</span><span style="color: #DD0000">"moldb.xml"</span><span style="color: #007700">);<br />echo&nbsp;</span><span style="color: #DD0000">"**&nbsp;Database&nbsp;of&nbsp;AminoAcid&nbsp;objects:\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$db</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
   After executing <var class="filename">parsemoldb.php</var>, the variable
   <var class="varname">$db</var> contains an array of
   <b class="classname">AminoAcid</b> objects, and the output of the
   script confirms that:
   <div class="informalexample">
    <div class="example-contents"><pre>
<div class="cdata"><pre>
** Database of AminoAcid objects:
Array
(
    [0] =&gt; aminoacid Object
        (
            [name] =&gt; Alanine
            [symbol] =&gt; ala
            [code] =&gt; A
            [type] =&gt; hydrophobic
        )

    [1] =&gt; aminoacid Object
        (
            [name] =&gt; Lysine
            [symbol] =&gt; lys
            [code] =&gt; K
            [type] =&gt; charged
        )

)
</pre></div>
    </pre></div>
   </div>
  </p>
 </div>


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