How do I get the value of a variable inside another - php

Question

I'm trying to get the $pi1 and $pi2 variable values inside of the add_custom_price function, but nothing seems to be working.
I have looked at setting variables to be accessible from function classes but I'm not sure I understand how to access them correctly.
add_filter( 'gform_confirmation', array(gravity_pi,custom_confirmation), 10, 4 );
class gravity_pi {
public $pi1;
public $pi2;
public function custom_confirmation( $confirmation, $form, $entry, $ajax, $product_id, $pi1, $pi2 ) {
if( $form['id'] == '2' ) {
$post = get_post( $entry['post_id'] );
$this->pi1 = rgar( $entry, '20' );
$this->pi2 = rgar( $entry, '21' );
$exclude_list = array("pi24","pi64","pi65","pi66","pi67","pi68","pi69","pi70","pi71","pi72","pi73","pi74","pi75","pi76","pi77","pi78","pi79","pi80","pi81","pi82");
if(!in_array($this->pi1, $exclude_list) && !empty($this->pi1)){
$target_product_id = '86';
$pid1 = '86';
}else{
$pid1 = preg_replace("/[^0-9,.]/", "", $this->pi1 );
}
if(!in_array($pi2, $exclude_list) && !empty($this->pi2)){
$target_product_id = '87';
$pid2 = '87';
}else{
$pid2 = preg_replace("/[^0-9,.]/", "", $this->pi2);
}
$product_ids = ''.$pid1.','.$pid2.'';
$url = 'https://*****.com/cart/?add-to-cart='.$product_ids.'';
$confirmation = array( 'redirect' => $url );
}
return $confirmation;
}
public function add_custom_price( $cart_object, $entry,$form, $field, $input_id ) {
foreach ( $cart_object->cart_contents as $key => $value ) {
if( 86 == $value['data']->id ) {
$value['data']->set_price( $this->pi1 );
}
if( 87 == $value['data']->id ) {
$value['data']->set_price( $this->pi2 );
}
}
}
}
add_action( 'woocommerce_before_calculate_totals', array(gravity_pi,add_custom_price));

Answer 1

You need to use $this to get/set any property in the class.
// set pi1 property value
$this->pi1 = 10;
//print/get property value
echo $this->pi1;

Answer 2

When you're setting the class properties (pi1 & pi2) you need to reference them in the same way you access them. Ex.
<?php
...
$this->pi1 = rgar($entry, '20');
Change all references (except where you declare them) of $pid1 to $this->pid1. Do this for $pid2 too.
Check this video out - https://www.youtube.com/watch?v=4c4nP7GLL1c