The function "range" is very useful to get an array of characters as range('C','R') does.

At work, I had to extend the function range($a,$b) to work in this special case: with two uppercase strings $a and $b, it should return all the possible strings between $a and $b.
This could be used for example to get the excel column indexes.
e.g. <?php range('A','AD') ==> array('A','B','C',...,'Z','AA','AB','AC','AD') ?>

So I wrote the function getrange($min,$max) that exactly does this.

<?php

function getcolumnrange($min,$max){
      $pointer=strtoupper($min);
      $output=array();
      while(positionalcomparison($pointer,strtoupper($max))<=0){
         array_push($output,$pointer);
         $pointer++;
      }
      return $output;
}

function positionalcomparison($a,$b){
   $a1=stringtointvalue($a); $b1=stringtointvalue($b);
   if($a1>$b1)return 1;
   else if($a1<$b1)return -1;
   else return 0;
}

/*
* e.g. A=1 - B=2 - Z=26 - AA=27 - CZ=104 - DA=105 - ZZ=702 - AAA=703
*/
function stringtointvalue($str){
   $amount=0;
   $strarra=array_reverse(str_split($str));

   for($i=0;$i<strlen($str);$i++){
      $amount+=(ord($strarra[$i])-64)*pow(26,$i);
   }
   return $amount;
}
?>