Algorithm to get the excel-like column name of a number

Here’s a nice simple recursive function (Based on zero indexed numbers, meaning 0 == A, 1 == B, etc)…

function getNameFromNumber($num) {
    $numeric = $num % 26;
    $letter = chr(65 + $numeric);
    $num2 = intval($num / 26);
    if ($num2 > 0) {
        return getNameFromNumber($num2 - 1) . $letter;
    } else {
        return $letter;
    }
}

And if you want it one indexed (1 == A, etc):

function getNameFromNumber($num) {
    $numeric = ($num - 1) % 26;
    $letter = chr(65 + $numeric);
    $num2 = intval(($num - 1) / 26);
    if ($num2 > 0) {
        return getNameFromNumber($num2) . $letter;
    } else {
        return $letter;
    }
}

Tested with numbers from 0 to 10000…

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