Deleting part of variable String in php - php

Question

I have the function get_price_data(); which gives "0,11\u20ac" as return value.
The "0,11" is not static.
I want to do some maths with "0,11" from the string below.
My Code shown down below does not work how i want it to. Has someone any idea how i can complete this task ? I am very new to php.
<?php
function get_price_data() {
$json = file_get_contents("http://steamcommunity.com/market/priceoverview/?currency=3&appid=730&market_hash_name=Chroma%202%20Case");
$decode = json_decode($json,1);
echo $decode['median_price'];
}
$string=get_price_data();
$string2 = str_replace("\u20ac","",$string);
echo $string2 * 1000 - 120;
?>

Answer 1

<?php
function get_price_data() {
$json = file_get_contents("http://steamcommunity.com/market/priceoverview/?currency=3&appid=730&market_hash_name=Chroma%202%20Case");
$decode = json_decode($json,1);
return $decode['median_price']; // return here instead of echo.
}
You are somewhat correct that this return is necessary because this is a function. A return statement is not specifically required in a PHP function (functions will return null by default if there is no explicit return value.) The reason you need it to return is that you are using its returned value in this statement:
$string=get_price_data();
With echo instead of return, $string will be set to null here, and any subsequent operations on it will obviously not do what you intended.
If you change your function to return the value of $decode['median_price'], then $string=get_price_data(); will assign 0,11€ to $string, and then your replacements and calculations should work as expected.
$string=str_replace(array('€','\u20ac'),'',$string);
$string = str_replace(",",".",$string); // replace , with . as noted by mertizci
echo $string * 1000 - 120;
?>

Answer 2

Because of the comma in the changed price value, PHP cant do math things on it. You should change the comma with dot too.
Your code should be (edited):
<?php
$string=get_price_data();
$string=str_replace(array('€','\u20ac'),'',$string);
$string = str_replace(",",".",$string);
echo $string * 1000 - 120;
?>