Extract data from XML attributes

Question

i have XML here http://xml.tab.co.nz/odds/2017-02-08 i want to retrieve 'number' attribute from meeting node, 'number' attribute from races node and 'win' attribute from entry node. They should be dependently extracted means meeting 2 race 1 then all win attributes of it. meeting 2 race 2 then all win attributes of it. and so on. i have tried this

$xmlDoc = new DOMDocument(); 
$xmlDoc->load( 'http://xml.tab.co.nz/odds/2017-02-08' ); 

$searchNode2 = $xmlDoc->getElementsByTagName( "meeting" ); 

foreach( $searchNode2 as $searchNode2 ) 
{ 
    $valueID2 = $searchNode2->getAttribute('number'); 
    $meetings[$k]=$valueID2;
    $k++;
    //echo "$valueID2\n"; 
}

$searchNode1 = $xmlDoc->getElementsByTagName( "race" ); 

foreach( $searchNode1 as $searchNode1 ) 
{ 
    $valueID1 = $searchNode1->getAttribute('number'); 
    $races[$j]=$valueID1;
    $j++;
    //echo "$valueID1\n"; 
}

$searchNode = $xmlDoc->getElementsByTagName( "entry" ); 

foreach( $searchNode as $searchNode ) 
{ 
    $valueID = $searchNode->getAttribute('win'); 
    $runners[$i]=$valueID;
    $i++;
    //echo "$valueID\n"; 
}

but every thing is independent and cant figure it out how to do so.

Answer 1

Consider SimpleXMLElement's XPath , walking down each tree level of the XML updating a two-level array that you encode at the end into json:

// Loading XML source
$xml = simplexml_load_file('http://xml.tab.co.nz/odds/2017-02-08');

// Initializing variables
$i = 0;
$data = [];

// Extracting values
foreach ($xml->xpath("//meeting") as $mtg){                      
   foreach ($mtg->xpath("races") as $races) {
      foreach ($races->xpath("race") as $race) {
         foreach ($race->xpath("entries") as $entries) {
            foreach ($entries->xpath("entry") as $entry) {
                $data[$i]['meeting'] = (string)$mtg->xpath("@number")[0];  
                $data[$i]['races'] = (string)$race->xpath("@number")[0];

                $win = 'win-'.(string)$entry->xpath("@number")[0];
                if ($entry->xpath("@win")) {
                    $data[$i][$win] = (string)$entry->xpath("@win")[0];
                } else {
                    $data[$i][$win] = '';
                }
            }
            $i++;    
         }             
       }
     }
}

// Encode json and export to external file
$json = json_encode($data, JSON_PRETTY_PRINT|JSON_UNESCAPED_UNICODE|JSON_UNESCAPED_SLASHES);
echo $json;

file_put_contents('Output.json", $json);

Output

[
    {
        "meeting": "2",
        "races": "1",
        "win-1": "8.90",
        "win-2": "14.70",
        "win-3": "2.80",
        "win-4": "54.80",
        "win-5": "13.10",
        "win-6": "7.10",
        "win-7": "13.30",
        "win-8": "8.60",
        "win-9": "4.40"
    },
    {
        "meeting": "2",
        "races": "2",
        "win-1": "5.50",
        "win-2": "6.10",
        "win-3": "6.80",
        "win-4": "4.80",
        "win-5": "14.70",
        "win-6": "4.20",
        "win-7": "35.00",
        "win-8": "12.40",
        "win-9": "28.00",
        "win-10": "23.50"
    },
    {
        "meeting": "2",
        "races": "3",
        "win-1": "8.70",
        "win-2": "9.10",
        "win-3": "13.70",
        "win-4": "1.70",
        "win-5": "17.00",
        "win-6": "11.70",
        "win-7": "5.30",
        "win-8": ""
    },
    ...