SimpleXML & PHP: Extract part of XML document & convert as Array

Question

Consider the following XML:

<?xml version="1.0" encoding="UTF-8"?>
<OS>
 <data>
 <OSes>
 <centos>
 <v_5>
 <i386>
 <id>centos5-32</id>
 <name>CentOS 5 - 32 bit</name>
 <version>5</version>
 <architecture>32</architecture>
 <os>centos</os>
 </i386>
 <x86_64>
 <id>centos5-64</id>
 <name>CentOS 5 - 64 bit</name>
 <version>5</version>
 <architecture>64</architecture>
 <os>centos</os>
 </x86_64>
 </v_5>
 <v_6>
 <i386>
 <id>centos6-32</id>
 <name>CentOS 6 - 32 bit</name>
 <version>6</version>
 <architecture>32</architecture>
 <os>centos</os>
 </i386>
 <x86_64>
 <id>centos6-64</id>
 <name>CentOS 6 - 64 bit</name>
 <version>6</version>
 <architecture>64</architecture>
 <os>centos</os>
 </x86_64>
 </v_6>
 </centos>
 <ubuntu>
 <v_10>
 <i386>
 <id>ubuntu10-32</id>
 <name>Ubuntu 10 - 32 bit</name>
 <version>10</version>
 <architecture>32</architecture>
 <os>ubuntu</os>
 </i386>
 <amd64>
 <id>ubuntu10-64</id>
 <name>Ubuntu 10 - 64 bit</name>
 <version>10</version>
 <architecture>64</architecture>
 <os>ubuntu</os>
 </amd64>
 </v_10>
 </ubuntu>
 </OSes>
 </data>
</OS>

From the XML document above, I want to extract following 5 element node

1. <id>
2. <name>
3. <version>
4. <architecture>
5. <os>

And have them as a array. I tried doing the following:

<?php 
require_once "xml.php";
 try {
 $xml = new SimpleXMLElement($xmlstr);
 foreach($xml->xpath(' //id | //name | //version// | //architecture | //os ') as $record) {
 echo $record;
 }
 } catch(Exception $e){
 echo $e->getMessage();
 }

the above code works but each record is an separate object. I want someone to consolidate all 5 elements nodes as one array element. something like this:

$osList = Array( [0] => Array(
 ["id"] => "<id>",
 ["name"] => "<name>",
 ["version"] => "<version>",
 ....
)
 .....
);

syntax isn't correct but you get the idea. any idea how to do this?

• Quasdunk: You might want to reconsider your XML structure (if it's yours)...
• CuriousMind: ^^^Trust me, if It was an option. I would have done it rightaway. this data is from External API over which I have no control.
• hakre: So you need to get the element-name as key and the value as value (hint, hint)?
• hakre: Don't you get this with your code? Warning: SimpleXMLElement::xpath(): Invalid expression
• Quasdunk: @Gaurish Alright, just didn't want to leave the option unmentioned :) The person who did this probably shouldn't be doing any more XML... :)

Answer 1

this might help

$obj = new SimpleXMLElement($xml);
$rtn = array();
$cnt = 0;
foreach($obj->xpath('///OSes/*/*') as $rec)
{
 foreach ($rec as $rec_obj)
 {
 if (!isset($rtn[$cnt]))
 {
 $rtn[$cnt] = array();
 }
 foreach ($rec_obj as $name=>$val)
 {
 $rtn[$cnt][(string)$name] = (string)$val;
 }
 ++$cnt;
 }
}

• CuriousMind: I never thought about this Xpath expression. Lovely!

Answer 2

By modifying the xpath as others suggested as well, I came to this conclusion. It works with one helper function to re-format each xpath result node and uses array_reduce to iterate over the result. It then returns the converted result (Demo):

$xml = new SimpleXMLElement($xmlstr);
$elements = array_reduce(
 $xml->xpath('//OSes/*/*'),
 function($v, $w) {
 $w = array_values((array) $w); // convert result to array
 foreach($w as &$d) $d = (array) $d; // convert inner elements to array
 return array_merge($v, $w); // merge with existing
 }, 
 array() // empty elements at start
);

Output:

Array
(
 [0] => Array
 (
 [id] => centos5-32
 [name] => CentOS 5 - 32 bit
 [version] => 5
 [architecture] => 32
 [os] => centos
 )
 [1] => Array
 (
 [id] => centos5-64
 [name] => CentOS 5 - 64 bit
 [version] => 5
 [architecture] => 64
 [os] => centos
 )
 [2] => Array
 (
 [id] => centos6-32
 [name] => CentOS 6 - 32 bit
 [version] => 6
 [architecture] => 32
 [os] => centos
 )
 [3] => Array
 (
 [id] => centos6-64
 [name] => CentOS 6 - 64 bit
 [version] => 6
 [architecture] => 64
 [os] => centos
 )
 [4] => Array
 (
 [id] => ubuntu10-32
 [name] => Ubuntu 10 - 32 bit
 [version] => 10
 [architecture] => 32
 [os] => ubuntu
 )
 [5] => Array
 (
 [id] => ubuntu10-64
 [name] => Ubuntu 10 - 64 bit
 [version] => 10
 [architecture] => 64
 [os] => ubuntu
 )
)

I also opted for converting the original xpath result into an array of two levels, each time within the current level a key already exists, move the current entry to a new entry (Demo):

try
{
 $xml = new SimpleXMLElement($xmlstr);
 $elements = array();
 $curr = NULL;
 foreach($xml->xpath('//id | //name | //version | //architecture | //os') as $record)
 {
 $key = $record->getName();
 $value = (string) $record;
 if (!$curr || array_key_exists($key, $curr)) {
 unset($curr);
 $curr = array();
 $elements[] = &$curr;
 }
 $curr[$key] = $value;
 }
 unset($curr);
}
catch(Exception $e)
{
 echo $e->getMessage();
}

Result is like this then:

Array
(
 [0] => Array
 (
 [id] => centos5-32
 [name] => CentOS 5 - 32 bit
 [version] => 5
 [architecture] => 32
 [os] => centos
 )
 [1] => Array
 (
 [id] => centos5-64
 [name] => CentOS 5 - 64 bit
 [version] => 5
 [architecture] => 64
 [os] => centos
 )
 [2] => Array
 (
 [id] => centos6-32
 [name] => CentOS 6 - 32 bit
 [version] => 6
 [architecture] => 32
 [os] => centos
 )
 [3] => Array
 (
 [id] => centos6-64
 [name] => CentOS 6 - 64 bit
 [version] => 6
 [architecture] => 64
 [os] => centos
 )
 [4] => Array
 (
 [id] => ubuntu10-32
 [name] => Ubuntu 10 - 32 bit
 [version] => 10
 [architecture] => 32
 [os] => ubuntu
 )
 [5] => Array
 (
 [id] => ubuntu10-64
 [name] => Ubuntu 10 - 64 bit
 [version] => 10
 [architecture] => 64
 [os] => ubuntu
 )
)

• CuriousMind: Thanks for your help. Based on your solution, I adapted mine. Thanks again :)

Answer 3

Try this:

// flatten:
function arrayval1($any) {
 return array_values((array)$any);
}
function arrayval2($any) {
 return (array)$any;
}
// xml objects with xml objects:
$oses = $xml->xpath('//OSes/*/*');
// an array of xml objects:
$oses = array_map('arrayval1', $oses);
// merge to a flat array:
$oses = call_user_func_array('array_merge', $oses);
// xml objects -> arrays
$oses = array_map('arrayval2', $oses);
print_r($oses);

My result:

Array
(
 [0] => Array
 (
 [id] => centos5-32
 [name] => CentOS 5 - 32 bit
 [version] => 5
 [architecture] => 32
 [os] => centos
 )
 [1] => Array
 (
 [id] => centos5-64
 [name] => CentOS 5 - 64 bit
 [version] => 5
 [architecture] => 64
 [os] => centos
 )
 [2] => Array
 (
 [id] => centos6-32
 [name] => CentOS 6 - 32 bit
 [version] => 6
 [architecture] => 32
 [os] => centos
 )
 [3] => Array
 (
 [id] => centos6-64
 [name] => CentOS 6 - 64 bit
 [version] => 6
 [architecture] => 64
 [os] => centos
 )
 [4] => Array
 (
 [id] => ubuntu10-32
 [name] => Ubuntu 10 - 32 bit
 [version] => 10
 [architecture] => 32
 [os] => ubuntu
 )
 [5] => Array
 (
 [id] => ubuntu10-64
 [name] => Ubuntu 10 - 64 bit
 [version] => 10
 [architecture] => 64
 [os] => ubuntu
 )
)

If you're using PHP>= 5.3 (ofcourse you are, why whouldn't you) you can omit the nasty tmp function definitions and use cool anonymous functions for the mapping:

// an array of xml objects:
$oses = array_map(function($os) {
 return array_values((array)$os);
}, $oses);