PHP SimpleXMLElement addChild in a loop only show once with largest value - php

Question

I have an XML file:
<include>
<data>
<name>Chicken</name>
<price>1</price>
</data>
<data>
<name>Fish</name>
<price>5</price>
</data>
...Cut off about 100 lines...
<data>
<name>Pig</name>
<price>105</price>
</data>
<include>
Now, I want to add the ascending <id>, right above the <name> like this:
<include>
<data>
<id>1203001</id>
<name>Chicken</name>
<price>1</price>
</data>
<data>
<id>1203002</id>
<name>Fish</name>
<price>5</price>
</data>
...Cut off about 100 lines...
<data>
<id>1203105</id>
<name>Pig</name>
<price>105</price>
</data>
<include>
I used the for loop, here is my code:
$data = <<<XML
<include>
<data>
<name>Chicken</name>
<price>1</price>
</data>
<data>
<name>Fish</name>
<price>5</price>
</data>
...Cut off about 100 lines...
<data>
<name>Pig</name>
<price>105</price>
</data>
<include>
XML;
for($i = 1203001; $i <= 1203105; $i++) {
$xml = new SimpleXMLElement($data);
$xml->data->addChild("id", $i);
}
echo $xml->asXML();
However, the result I get is that <id> only appears once, with the largest value, next to </data> instead of the position I want::
<include>
<data>
<name>Chicken</name>
<price>1</price>
<id>1203105</id></data>
<data>
<name>Fish</name>
<price>5</price>
</data>
...
Please show me a method to solve this problem. I would appreciate your solution.

Answer 1

You're recreating $xml from $data every time through the loop, so you're discarding the changes you made on the previous iteration.
Initialize $xml before the loop. Then loop over the data child nodes.
$xml = new SimpleXMLElement($data);
$i = 1203001;
foreach ($xml->data as $node) {
$node->addChild("id", $i++);
}
If you want to insert <id> at the beginning of the <data> node instead of the end, see SimpleXML how to prepend a child in a node?