Function of php: after the value is processed by function, then spit back the function display, how to do it?

hypothetical

function number($id){
   //....

 sizeof($array); // 
}
<?= number(id);?>

when number is complete, there will be a value
how can I write
to my function so that it will be printed ?

return number (); ?

Mar.05,2021

return $array;

return sizeof ($array);

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bbe4b8-303d7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bbe4b8-303d7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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