表达式删除两个相似的字符和其他尾随字符

Question

I have a php reg expression that removes any special character from any string and replaces the character with a hyphen. The problem is that if there are two special characters following each other, I get two hyphens. for example if I type the text test@hhh%^ I get test-hhh-- or if I type test@hhh%^kkk I get test-hhh--kkk. I want my expression to give me test-hhh. I want to remove two similar hyphens following each other plus any trailing hyphens in the string. My code is here

$slug = preg_replace('/[^a-zA-Z0-9]/', '-', $slug);

Answer 1

First apply this regex to your string:

$slug = preg_replace('#-{2,}#', '-', $slug);

Secondly you apply a right trim (or a regular one) with a hyphen character as an extra argument.

$slug = trim($slug, '-');