PHP preg_replace pattern only seems to work if its wrong?

Question

I have a string that looks like this

../Clean_Smarty_Projekt/tpl/templates_c\\.
../Clean_Smarty_Projekt/tpl/templates_c\\..

I want to replace <

Answer 1

I suggest you to use a different php delimiter. Within the / delimiter, you need to use three \\\ or four \\\\ backslashes to match a single backslash.

$string = '../Clean_Smarty_Projekt/tpl/templates_c\.'."\n".'../Clean_Smarty_Projekt/tpl/templates_c\..';
echo preg_replace('~\.\./|\\\.{1,2}~', '', $string)

Output:

Clean_Smarty_Projekt/tpl/templates_c
Clean_Smarty_Projekt/tpl/templates_c