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<?php $string = "(Here {is [a] Special} Title)! & it's fine, right?"; echo preg_replace('~[^a-z]~', '_', strtolower($string)); // all non-letters become underscores echo "\n\n"; echo str_replace(' ', '_', preg_replace('~[^a-z ]+~', '', strtolower($string))); // notice the consecutive underscores echo "\n\n"; echo preg_replace(['~[^a-z ]+~', '~ +~'], ['', '_'], strtolower($string)); // notice no consecutive underscores
Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
_here__is__a__special__title_____it_s_fine__right_ here_is_a_special_title__its_fine_right here_is_a_special_title_its_fine_right
preferences:
134.88 ms | 408 KiB | 5 Q