How do I remove http, https and slash from user input in php

You want to use implode for this.

ie: $commaList = implode(', ', $fruit);

There is a way to append commas without having a trailing one. You'd want to do this if you have to do some other manipulation at the same time. For example, maybe you want to quote each fruit and then separate them all by commas:

$prefix = $fruitList = '';
foreach ($fruits as $fruit)
{
    $fruitList .= $prefix . '"' . $fruit . '"';
    $prefix = ', ';
}

Also, if you just do it the "normal" way of appending a comma after each item (like it sounds you were doing before), and you need to trim the last one off, just do $list = rtrim($list, ', '). I see a lot of people unnecessarily mucking around with substr in this situation.

Ok, let’s try this complete example of use:

function CatRemove($myXML, $id) {
    $xmlDoc = new DOMDocument();
    $xmlDoc->load($myXML);
    $xpath = new DOMXpath($xmlDoc);
    $nodeList = $xpath->query('//category[@id="'.(int)$id.'"]');
    if ($nodeList->length) {
        $node = $nodeList->item(0);
        $node->parentNode->removeChild($node);
    }
    $xmlDoc->save($myXML);
}

// test data
$xml = <<<XML
<?xml version="1.0"?>
<details>
 <person>name</person>
 <data1>some data</data1>
 <data2>some data</data2>
 <data3>some data</data3>
 <category id="0">
  <categoryName>Cat 1</categoryName>
  <categorydata1>some data</categorydata1>
 </category>
 <category id="1">
  <categoryName>Cat 2</categoryName>
  <categorydata1>some data</categorydata1>
  <categorydata2>some data</categorydata2>
  <categorydata3>some data</categorydata3>
  <categorydata4>some data</categorydata4>
 </category>
</details>
XML;
// write test data into file
file_put_contents('untitled.xml', $xml);
// remove category node with the id=1
CatRemove('untitled.xml', 1);
// dump file content
echo '<pre>', htmlspecialchars(file_get_contents('untitled.xml')), '</pre>';