sa-postcodes-to-provinces.php

<?php

$postcode = $argv[1];

$regionMap = [
    'EC' => [
        ['4731', '5199'],
        ['5200', '5299'],
        ['5300', '5499'],
        ['5500', '5999'],
        ['6000', '6099'],
        ['6100', '6499'],
    ],
    'FS' => [
        ['9300', '9399'],
        ['9400', '9699'],
        ['9700', '9899'],
        ['9900', '9999'],
    ],
    'GT' => [
        ['0001', '0299'],
        ['1400', '1699'],
        ['1700', '1799'],
        ['1800', '1999'],
        ['2000', '2199'],
    ],
    'NL' => [
        ['2900', '3199'],
        ['3200', '3299'],
        ['3300', '3599'],
        ['3600', '3799'],
        ['3800', '3999'],
        ['4000', '4099'],
        ['4100', '4299'],
        ['4300', '4499'],
        ['4500', '4730'],
    ],
    'LP' => [
        ['0500', '0698'],
        ['0699', '0999'],
    ],
    'MP' => [
        ['1000', '1399'],
        ['2200', '2499'],
    ],
    'NC' => [
        ['8100', '8100'],
        ['8300', '8799'],
        ['8800', '8999'],
    ],
    'NW' => [
        ['0300', '0499'],
        ['2500', '2899'],
    ],
    'WC' => [
        ['6500', '6699'],
        ['6700', '6899'],
        ['6900', '7099'],
        ['7100', '7299'],
        ['7300', '7399'],
        ['7400', '7599'],
        ['7600', '7699'],
        ['7700', '8099'],
    ]
];

$postcode = (int)$postcode;

// if empty return null
if ($postcode === 0) {
    echo "failed";
}
foreach ($regionMap as $province => $provinceCodes) {
    foreach ($provinceCodes as $code) {
        if ($postcode >= (int)$code[0] && $postcode <= (int)$code[1]) {
            echo $province . PHP_EOL;
        }
    }
}
echo "failed";