Question

If I have this pattern to build ID’s:

CX00 where the 0’s are replaceable with just a number.. but the following is already in use:

- CX00
- CX02
- CX04
- CX05
- CX07
- CX10
- CX11
- CX12

How can I easily find, either via PHP or MySQL the values CX01, CX03, CX06, CX08, CX09, CX13+ as available values?

Answer 1

I don’t know how your data is stored, so I’ll leave getting the IDs in an array. Once you do, this will find the next available one.

<?php

function make_id($n) {
    $out = 'CX';
    if ($n < 10) $out .= '0';
    return $out . $n;
}

// Get these from some source
$items = array('CX00', 'CX02', 'CX04', 'CX05');
$id = make_id(0);

for($i=0; in_array($id, $items); $i++)
    $id = make_id($i);

echo $id;

?>

This is called a brute-force method, and if you have a lot of IDs there are probably more efficient ways. With 100 maximum, there shouldn’t be any problems.