PHP implements the replacement of multiple strings into the same code

$name = 'Today 3? , very/ cold';
$name = strtolower($name);
//$name = preg_replace('/[^a-z0-9s ]/','',$name);
$name = preg_replace('/[.s+?,/"]/','_',$name); //change spaces
echo $name;
?> ;

where:

$name = preg_replace('/[.s+?,/"]/','_',$name); //change spaces

.s+?,/" is a regular expression, indicating search. The empty symbol ? / " these five characters Others can be added by yourself. If you don’t understand something, you can refer to the content about regular expressions.