Issue

It is necessary to clean a string from everything but English letters, spaces and specific numbers (eg 18,19,20 should be kept in the string).

Please help me with regex /([^a-zA-Z\s])/ to keep the specified numbers.

Solution

You can list the numbers that you want to keep between word boundaries for example and then make use of SKIP FAIL:

\b(?:1[89]|20)\b(*SKIP)(*F)|[^a-zA-Z\s]+

$pattern = "/\b(?:1[89]|20)\b(*SKIP)(*F)|[^a-zA-Z\s]+/";
$s="test 18 119 19 50 20 #@$@#%";
echo preg_replace($pattern, "", $s);

Output

test 18  19  20

Answered By - The fourth bird

Answer Checked By - Robin (PHPFixing Admin)