php str_replace under score and dash from string code example

Example 1: php replace spaces with dash

str_replace(' ', '-', $string);

Example 2: php replace all spaces with dashes

// Clean up multiple dashes or whitespaces
$string = preg_replace("/[\s-]+/", " ", $string);
// Convert whitespaces and underscore to dash
$string = preg_replace("/[\s_]/", "-", $string);