CODEWITHSUNDEEP
phpxmldomxml-parsing
Anand kumar
Anand kumar

Reputation: 17

how confirm / check weather a tag exists or not in XML

I'm trying to read the XML using DOM parser. My XML is dynamic so I cannot say always all values / tags will present in the XML. In this case i need to check the tag whether it is exists or not before reading it.

I tried like this as well

if($val->getElementsByTagName("cityName") != null) {

}

if(!empty($val->getElementsByTagName("cityName"))) {

}

getting error : Fatal error: Call to a member function getElementsByTagName() on a non-object in F:\xampp\htdocs\test\static-data.php on line 160

Any solution to find the tag existence. As like has Attribute as we check weather Attribute is there or not.

Upvotes: 0

Views: 242

Answers (1)

ThW
ThW

Reputation: 19512

If you use Xpath to fetch the nodes, you can avoid the validation.

Load some XML and create an DOMXpath instance for it.

$xml = <<<XML
<phoneNumbers>
  <phoneNumber type="home">212 555-1234</phoneNumber>
  <phoneNumber type="fax">646 555-4567</phoneNumber>
</phoneNumbers>
XML;

$dom = new DOMDocument();
$dom->loadXml($xml);
$xpath = new DOMXpath($dom);

Get the "home" phone number:

var_dump(
  $xpath->evaluate('string(/phoneNumbers/phoneNumber[@type="home"])')
);

Output:

string(12) "212 555-1234"

No "mobile" number exists, so the result is an empty string

var_dump(
  $xpath->evaluate('string(/phoneNumbers/phoneNumber[@type="mobile"])')
);

Output:

string(0) ""

You can count the numbers:

var_dump(
  [
    'all' => $xpath->evaluate('count(/phoneNumbers/phoneNumber)'),
    'home' => $xpath->evaluate('count(/phoneNumbers/phoneNumber[@type="home"])'),
    'fax' => $xpath->evaluate('count(/phoneNumbers/phoneNumber[@type="fax"])'),
    'mobile' => $xpath->evaluate('count(/phoneNumbers/phoneNumber[@type="mobile"])')
  ]
);

Output:

array(4) {
  ["all"]=>
  float(2)
  ["home"]=>
  float(1)
  ["fax"]=>
  float(1)
  ["mobile"]=>
  float(0)
}

Or iterate the numbers

foreach ($xpath->evaluate('/phoneNumbers/phoneNumber') as $phoneNumber) {
  var_dump(
    $phoneNumber->getAttribute('type'),
    $phoneNumber->nodeValue
  );
}

Output:

string(4) "home"
string(12) "212 555-1234"
string(3) "fax"
string(12) "646 555-4567"

Full example: https://eval.in/123212

Upvotes: 1

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