easy!

$xml = simplexml_load_string($xmlstring, "SimpleXMLElement", LIBXML_NOCDATA);
$json = json_encode(array = json_decode($json,TRUE);

Easiest way to do this is to use the built in functions, then convert to an array.

<?php
$obj = simplexml_load_string($xml); // Parse XML
$array = json_decode(json_encode($obj), true); // Convert to array
?>

You can json_encode() then json_decode() as array and use simplexml_load_string()

Steps:

1) First convert your XML into readable string object using simplexml_load_string().

2) Then json_encode() it.

3) json_decode() it, with second parameter TRUE, which will return array instead of object.

4) Now, your XML is converted into an array.

5) Take a blank array, loop over array from above code and append elements to it.

To get desired output:

<?php
$xml = '<?xml version = "1.0" encoding = "utf-8"?>
<tutorialspoint>

<course category = "JAVA">
  <title lang = "en">Java</title>
  <tutor>Gopal</tutor>
  <duration>3</duration>
  <price>$30</price>
</course>

<course category = "HADOOP">
  <title lang = "en">Hadoop</title>.
  <tutor>Satish</tutor>
  <duration>3</duration>
  <price>$50</price>
</course>

<course category = "HTML">
  <title lang = "en">html</title>
  <tutor>raju</tutor>
  <duration>5</duration>
  <price>$50</price>
</course>

<course category = "WEB">
  <title lang = "en">Web Technologies</title>
  <tutor>Javed</tutor>
  <duration>10</duration>
  <price>$60</price>
</course>
</tutorialspoint>';

$arr = [];
$array = json_decode(json_encode(simplexml_load_string($xml)),true);
if ( ! empty($array)) {
 $i=0;
 foreach ($array['course'] as $elem) {
   $arr[$i]['title'] = $elem['title'];
   $arr[$i]['tutor'] = $elem['tutor'];
   $arr[$i]['duration'] = $elem['duration'];
   $arr[$i]['price'] = $elem['price'];
  ++$i;
 }
}
echo '<pre>';print_r($arr);echo '</pre>';

Output:

Array
(
    [0] => Array
        (
            [title] => Java
            [tutor] => Gopal
            [duration] => 3
            [price] => $30
        )

    [1] => Array
        (
            [title] => Hadoop
            [tutor] => Satish
            [duration] => 3
            [price] => $50
        )

    [2] => Array
        (
            [title] => html
            [tutor] => raju
            [duration] => 5
            [price] => $50
        )

    [3] => Array
        (
            [title] => Web Technologies
            [tutor] => Javed
            [duration] => 10
            [price] => $60
        )

)

Working Code: