PHP | XMLReader lookupNamespace() Function

The XMLReader::lookupNamespace() function is an inbuilt function in PHP which is used to lookup in scope namespace for a given prefix.

Syntax:

string XMLReader::lookupNamespace( string $prefix )

Parameters: This function accepts a single parameter $prefix which holds the string containing the prefix.

Return Value: This function returns TRUE on success or FALSE on failure.

Below given programs illustrate the XMLReader::lookupNamespace() function in PHP:

Program 1:
Filename: data.xml

<?xml version="1.0" encoding="utf-8"?>
<div xmlns:z="my_namespace">
    <z:h1 z:attrib="value"> Foo Bar </z:h1>
</div>

Filename: index.php

<?php

// Create a new XMLReader instance
$XMLReader = new XMLReader();

// Open the XML file
$XMLReader->open('data.xml');

// Read the node
$XMLReader->read();

// Get the namespace with prefix y
$NS = $XMLReader->lookupNamespace("y");

// Show the namespace to browser
echo $NS;
?>

Output:

// Empty string because there is no namespace with prefix y.

Program 2:
Filename: data.xml

<?xml version="1.0" encoding="utf-8"?>
<div xmlns:x="geeksforgeeks">
    <x:h1 x:attrib="value"> Namespaced Text </x:h1>
</div>

Filename: index.php

<?php

// Create a new XMLReader instance
$XMLReader = new XMLReader();

// Open the XML file
$XMLReader->open('data.xml');

// Read the node
$XMLReader->read();

// Get the namespace with prefix x
$NS = $XMLReader->lookupNamespace("x");

// Show the namespace to browser
echo $NS;
?>

Output:

geeksforgeeks

Reference: https://www.php.net/manual/en/xmlreader.lookupnamespace.php