How to get a specific value in SimpleXML by specified attributes? - php

Question

The structure of my XML file is:
<?xml version="1.0" encoding="UTF-8"?>
....
..
.
<usernames>
<user id="harrypotter">
<topicid id="1">
<commentid>1</commentid>
</topicid>
<topicid id="2">
<commentid>2</commentid>
</topicid>
<topicid id="3">
<commentid>3</commentid>
</topicid>
<topicid id="4">
<commentid>4</commentid>
</topicid>
<topicid id="5">
<commentid>5</commentid>
</topicid>
<topicid id="6">
<commentid>6</commentid>
</topicid>
<topicid id="7">
<commentid>7</commentid>
</topicid>
<topicid id="8">
<commentid>8</commentid>
</topicid>
<topicid id="9">
<commentid>9</commentid>
</topicid>
<topicid id="10">
<commentid>10</commentid>
</topicid>
<topicid id="11">
<commentid>11</commentid>
</topicid>
</user>
....
..
.
</usernames>
I have a function to get a comment by passing a topic, and a username. My function is:
function getComment($var_topicid, $usrname)
$xml2=simplexml_load_file("comment.xml") or die("Error: Cannot create object");
foreach ($xml2->user as $user){
if ($user['id'] == $usrname){
if($user->topicid['id'] == $var_topicid){
return $user->topicid->commentid;
}
}
}
}
I try to get a comment by passing the values, but it does not return anything.
$x = getComment('2','harrypotter'));
print $x;
Could you please give some suggestion?
Thank you.

Answer 1

I found a solution by applying xpath:
$myDataObjects = $xml2->xpath('//usernames/user[#id="harrypotter"]/topicid[#id="2"]/commentid');
print $myDataObjects[0][0];
More details: SimpleXML: Selecting Elements Which Have A Certain Attribute Value

Answer 2

Also you're not looping on the user nodes : the topicid, you should add a foreach, it should look like this :
function getComment($var_topicid, $usrname)
$xml2=simplexml_load_file("comment.xml") or die("Error: Cannot create object");
foreach ($xml2->user as $user){
if ($user['id'] == $usrname){
foreach (user->topicid as $topic){
if($topic['id'] == $var_topicid){
return $topic->commentid;
}
}
}
}
}