Simplexml calculate 2 value from 2 files

[dumb2champ]

Hello...

I want to calculate the value from 2 difference files using simplexml load file...

But the result not as expected..

 

 

My output should be 7 and 5 where 10 - 7 and 8 - 3.

 

My first xml files.

    <?xml version="1.0" encoding="UTF-8"?>
    <items>
      <item>
        <q_id>4131001</q_id>
        <value>10</value>
      </item>
      <item>
        <q_id>4232002</q_id>
        <value>8</value>
      </item>
    </items>

My second xml files.

    <?xml version="1.0" encoding="UTF-8"?>
    <items>
      <item>
        <q_id>4131001</q_id>
        <value>7</value>
      </item>
      <item>
        <q_id>4232002</q_id>
        <value>3</value>
      </item>
    </items>

My scripts.

    <?php

    $xml = simplexml_load_file('q1.xml');
    $xml2 = simplexml_load_file('q2.xml');

    foreach ($xml -> item as $item) {

	$value1 = $item->value;
	
	echo $item->q_id.'<br />';
	//echo $value1.'<br />';

	foreach ($xml2 -> item as $item2) {

		$value2 = $item2->value;
		
		$total = $value1 - $value2;

		echo $total.'<br />';

	}

    }

    ?>

The result should be 7 and 5 where 10 - 7 and 8 - 3 but there is another unknows value which is 3 and 1...

 

How to solve the issue..

 

Thank for any help..

[dumb2champ]

sory the result should be 3 and 5...sory

[Barand]

That's because you have nested the loops. Do something like this

$xml1 = simplexml_load_file('q1.xml');
$xml2 = simplexml_load_file('q2.xml');

$a1 = [];
foreach ($xml1->xpath('//item') as $i) {
    $a1[(string)$i->q_id] = (int)$i->value;
}
$a2 = [];
foreach ($xml2->xpath('//item') as $i) {
    $a2[(string)$i->q_id] = (int)$i->value;
}

foreach ($a1 as $id => $v) {
    echo $id . '<br>';
    $result = $v - $a2[$id];
    echo $result . '<br>'; 
}

[dumb2champ]

I got Notice: Undefined offset: 4131001

 

Output

 

4131001

Notice: Undefined offset: 4131001 on line 17
10
4232002
5

[Barand]

Have you checked the xml files - is 4131001 in both of them?

[dumb2champ]

Thanks Barrand..

 

One more question..i dont quite understand the codes which is:

 

foreach ($xml2->xpath('//item') as $i) {
    $a1[(string)$i->q_id] = (int)$i->value;
}

 

If i want to add another object say, <q_name>This is Q1<q_name> after  <q_id> which is like this:

 

<item>
<q_id>4131001</q_id>

<q_name>This is Q1<q_name> <-----
<value>7</value>
</item>

 

How to edit the scripts?

[dumb2champ]

What i mean was to output <q_name> object..thanks

[Barand]

foreach ($xml2->xpath('//item') as $i) {
    $a1[(string)$i->q_id] = (int)$i->value;
}

the code scans all the items in the xml data and stores them in an array with the id as the key.

 

If you add "q_name" then the values will be changed to arrays containing the name and the value

$xml1 = simplexml_load_file('q1.xml');
$xml2 = simplexml_load_file('q2.xml');

$a1 = [];
foreach ($xml1->xpath('//item') as $i) {
    $a1[(string)$i->q_id] = ['name' => (string)$i->q_name, 'value' => (int)$i->value];
}
$a2 = [];
foreach ($xml2->xpath('//item') as $i) {
    $a2[(string)$i->q_id] = ['name' => (string)$i->q_name, 'value' => (int)$i->value];
}

foreach ($a1 as $id => $v) {
    echo $id . '<br>';
    echo (string)$v['name'] . '<br>';
    $result = $v['value'] - $a2[$id]['value'];
    echo $result . '<br><br>'; 
}