<?php
 
	function column_id_to_int($columnId) {
		if (!$columnId)
			throw new DomainException("Column-id cannot be empty.");
		$columnId = strtoupper($columnId);
		if ( !preg_match('~[A-Z]+~',$columnId) )
			throw new DomainException("String '$columnId' is not a valid column-id.");
		$sum = 0;
		for ($x=0; $x<strlen($columnId); $x++ ) {
			$sum = $sum*26;
			$sum += (ord($columnId[$x]) - 65 + 1);
		}
		return $sum;
	}
 
	print 'AA <=> ' . column_id_to_int('AA') . "\n";
	print 'ABC <=> ' . column_id_to_int('ABC') . "\n";
 
?>

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