在PHP中意外返回rtrim函数

Question

when i use:

rtrim('HeaderController', 'Controller');

i'm expecting to this will return Header because HeaderController - Controller = Header but this returns 'Head', why?

Answer 1

if you want to remove the "Controller" substring you can do it like this:

$name = 'HeaderController';
$shortName = str_replace('Controller', '', $name);

to be sure to replace only "Controller" in the end of the string you need a regular expression (which is a little slower)

$name = 'HeaderController';
$shortName = preg_replace('/Controller$/', '', $name);

The $-sign marks the end of the string