Remove a part of a string, but only when it is at the end of the string

Question

I need to remove a substring of a string, but only when it is at the END of the string.

for example, removing \'string\' at the end of the following strings :

Answer 1

You can use rtrim().

php > echo rtrim('this is a test string', 'string');
this is a test 

This will work only in some cases, as 'string' is just a characters mask and char order will not be respected.