Introduction to PHP reading xml method_PHP tutorial
1. What is xml and what is it used for?
XML (Extensible Markup Language) is an extensible markup language. Like HTML, it is SGML (Standard Generalized Markup Language). markup language). Xml is a cross-platform, content-dependent technology in the Internet environment, and is currently a powerful tool for processing structured document information. Extensible Markup Language XML is a simple data storage language that uses a series of simple tags to describe data, and these tags can be established in a convenient way. Although XML takes up more space than binary data, XML is extremely Simple and easy to master and use.
XML has many uses. It can be used to store data, exchange data, prompt data for many kinds of application software, etc.
Second, how to read xml with php
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1) DOMDocument reads xml
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The code is as follows:
$doc->load('person.xml'); //Read xml file
$humans = $doc->getElementsByTagName( "humans" ); //Get the object array of the humans tag
$old = $olds->item(0)->nodeValue;
echo "$name - $sex - $oldn";
}
?>
2) simplexml reads xml
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The code is as follows:
foreach($xml_array as $tmp){
echo $tmp->name."-".$ tmp->sex."-".$tmp->old."
";
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The code is as follows:
$f = fopen('person.xml', 'r');
while( $data = fread( $f, 4096 ) ) {
preg_match_all( "/
preg_match_all( "/
preg_match_all( "/
}
foreach ($name[1] as $key=>$val){
echo $val." - ".$sex[$key][1]." - ".$old[$key][1] ."
" ;
}
?>
4) xmlreader to read xml data
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The code is as follows:
$reader->open('person.xml' ); //Read xml data
$i=1;
" ;
$i++;
}
}
?>
3. Summary
There are many ways to read xml, here are a few. The above four methods can all read the data in the tag, Zhang Ying. But their testing focus is different. The design focus of the function of reading xml in the first three methods is to read the value in the tag, which is equivalent to The text() method in jquery is different from xmlreader. Its focus is not on reading the value in the tag, but on reading the attributes of the tag and putting all the data to be transmitted in the attributes (but as I mentioned above The method I wrote still takes the value in the tag, because the xml file has been given, and I don’t want to create the xml file again).
Give an example to explain,

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Multiple calls to session_start() will result in warning messages and possible data overwrites. 1) PHP will issue a warning, prompting that the session has been started. 2) It may cause unexpected overwriting of session data. 3) Use session_status() to check the session status to avoid repeated calls.

Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.


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