John Davidson

Message:

I am practicing with XML DOM PHP parsing. I have such XML file (shorter version):

<?xml version="1.0" encoding="UTF-8"?>

<tabela_kursow typ="A" uid="21a184">

   <numer_tabeli>184/A/NBP/2021</numer_tabeli>

   <data_publikacji>2021-09-22</data_publikacji>

   <pozycja>

      <nazwa_waluty>bat (Tajlandia)</nazwa_waluty>

      <przelicznik>1</przelicznik>

      <kod_waluty>THB</kod_waluty>

      <kurs_sredni>0,1181</kurs_sredni>

   </pozycja>

   <pozycja>

      <nazwa_waluty id="2">dolar amerykański</nazwa_waluty>

      <przelicznik>1</przelicznik>

      <kod_waluty>USD</kod_waluty>

      <kurs_sredni>3,9460</kurs_sredni>

   </pozycja>

</tabela_kursow>

I created attribute with name "id" and value "2" for two Tag elements.

<?php

$doc = new DOMDocument();

$doc->load("kursy_walut.xml");

$doc->preserveSpace = false;

$doc->formatOutput = true;





$a = $doc->getElementsByTagName("nazwa_waluty");

$b = count($a);

for ($i=0; $i<$b; $i++){

    $c = $a[$i]->childNodes[0]->nodeValue;

    if ($c === 'dolar amerykański'){

        $a[$i]->setAttribute('id', '2');

    }

    if ($c === 'euro'){

        $a[$i]->setAttribute('id', '2');

    }

}

$doc->save('output.xml');

Now I would like to:

1. Get only Tag elements which did not contain attribute 'id="2"';


2. Get only Tag elements which contain only 'id="2"'.

For first case I created such code. Don't know exactly how to create second case.

$doc3 = new DOMDocument();

$doc3->preserveWhiteSpace = false;

$doc3->load('output.xml');

$xpath2 = new DOMXPath($doc3);

$id3 = $xpath2->query('//*/pozycja/nazwa_waluty[@id="2"]');

foreach($id3 as $attr){

    $attr->parentNode->removeChild($attr);

}

$doc3->formatOutput = true;

$doc3->save('output3.xml');

Maybe someone can help me with second case?
Thank you.

---

My Answer:
xml


Child 1
Child 2
Child 3




To remove a child element with a specific attribute value using PHP's DOMDocument, you can use the following code:

php
$xml = '

Child 1
Child 2
Child 3

';

$doc = new DOMDocument();
$doc->loadXML($xml);

$xpath = new DOMXPath($doc);
$nodes = $xpath->query('//child[@id="2"]');

foreach ($nodes as $node) {
$node->parentNode->removeChild($node);
}

echo $doc->saveXML();
?>


In this code snippet, we first load the XML string into a DOMDocument object. We then use a DOMXPath object to query for the child element with the attribute `id="2"`. We iterate over the resulting nodes and remove each node from its parent node using the `removeChild()` method. Finally, we output the modified XML using the `saveXML()` method.