PhpSpreadsheetを使うと欲しくなる関数

coords.php

<?php

use PhpOffice\PhpSpreadsheet\Cell\Coordinate;

function coords(int $startCol, int $startRow, ?int $endCol = null, ?int $endRow = null): string
{
	$coords = Coordinate::stringFromColumnIndex($startCol) . $startRow;
	if (isset($endRow)) {
		$coords .= ':' . Coordinate::stringFromColumnIndex($endCol) . $endRow;
	}
	return $coords;
}