<?php
$string = <<<POST
wow, that film was #hilarious
I #love turtles
#YouTube has funny videos that I #love <3
POST;
preg_match_all('/#(\w+)\b/', $string, $matches);
var_dump(array_count_values($matches[1]));
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
array(3) {
["hilarious"]=>
int(1)
["love"]=>
int(2)
["YouTube"]=>
int(1)
}