SimpleXML a little note _php tutorial

SimpleXML provides a simple and fast method of XML operation, which greatly improves the efficiency of XML operation. But sometimes careless can bring a little trouble, look at the following code:

$xml = simplexml_load_string ( Title );

$title = $xml->title;

echo $title;

$xml->title = test;

echo $title;

Guess what the second output would be? It's test, not the imaginary title. Why is that? Here's why:

Echo GetType ($xml->title)//Object

Echo Get_class ($xml->title); SimpleXMLElement

See, $xml->title is an instance of a SimpleXMLElement class, not a string. So $title actually holds a reference to the SimpleXMLElement class, not a copy of the string. To get a copy of a string, you can only type conversions:

$title = (string) $xml->title; Get string

$xml->title = test;

echo $title; Output title

SimpleXMLElement should be implemented in a similar way to __tostring () interface (interested can go to see the source code of PHP, in "ext/simplexml/"), in the Echo and other expressions like a string. So there's another place to be aware of:

$_session[test] = $xml->title; Save a SimpleXMLElement variable to the session.

$_session[test] = (string) $xml->title; String

$_session[test] = Strval ($xml->title); That's OK.

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