- var_dump: documentation ( source)
- filter_var: documentation ( source)
- range: documentation ( source)
<?php
var_dump( filter_var( range(1, 3), FILTER_VALIDATE_INT, FILTER_REQUIRE_ARRAY ) );
var_dump( filter_var( 3, FILTER_VALIDATE_INT, FILTER_FORCE_ARRAY ) );
var_dump( filter_var( 3, FILTER_VALIDATE_INT, FILTER_REQUIRE_ARRAY ) );