PHP Function - Unknown Failure - php

Question

I'm fairly new to coding and just recently started working on integrating functions into my PHP. I am trying to encode and echo an IP address to Google Analytics's. This is what my custom modifier looks like:
pagetracker._setCustomVar(1, "IP", "<?php include function.php; echo remove_numbers_advanced($_SERVER['REMOTE_ADDR']); ?>", 2);
The function file looks like this:
<?
function remove_numbers_advanced($string)
{
$numbers = array();
for($counter =0; $counter <= 10; $counter++) {
$numbers[$counter] = $counter;
$replacements = array("A","7","B","6","C","4","D","3","E","F");
$string = str_replace($numbers, $replacements, $string);
return $string;
}';
echo remove_numbers_advanced($string);
?>
When I isolated the PHP section of my custom variable in an attempt to test it the page throws a 500 error, suggesting to me that there is something wrong with how I have my script set up.
Please bear in mind I am rather new to this so simple terms and examples would help a ton!

Answer 1

There are few errors in your function. The correct function is:
function remove_numbers_advanced($string)
{
$numbers = array();
for($counter =0; $counter <= 10; $counter++)
$numbers[$counter] = $counter;
$replacements = array("A","7","B","6","C","4","D","3","E","F");
$string = str_replace($numbers, $replacements, $string);
return $string;
}
1- You added open curly braces next to for loop but did not close it
2- Also there is " '; " at the closing braces of function. It shouldn't be there.

Answer 2

include function must have a string parameter so put '' around file name
pagetracker._setCustomVar(1, "IP", "<?php include 'function.php'; echo remove_numbers_advanced($_SERVER['REMOTE_ADDR']); ?>", 2);