Something

<?php
$part_numbers="t";
$price="f";

$cre_bool_array = array( "part_numbers" => "$part_numbers",
                    "price" => "$price" );


    echo "part_numbers: $part_numbers<br>";

    foreach($cre_bool_array as $name => &$value) {
        if(is_string($value)) {
            if($value == 't') {
                $value = "Yes";
                echo "$name,$value<br>";
            }
            continue;
        }
    }
    echo "part_numbers: $part_numbers<br>";


?>