Cannot create php str_replace () to remove comma

Question

In a PHP project, I have:

$string = "1,555"; str_replace(',', '', $string); echo $string; //is still 1,555 

str_replace does not remove the comma. If I var_dump. I get string(5) "1,555"

Any ideas? I just need to remove the commas so that I can calculate.

Answer 1

 $string = str_replace(',', '', $string);