Numbers to letters with logical sequence - php

Question

I have this array which links numbers to letters at the moment like this:
1-26 = A-Z
But there is more, 27=AA and 28=AB etc...
so basically when I do this:
var_dump($array[2]); //shows B
var_dump($array[29]); //shows AC
Now this array I made myself but it's becoming way too long. Is there a way to actually get this going on till lets say 32? I know there is chr but I dont think I can use this.
Is there an easier way to actually get this without using this way too long of an array?

Answer 1

It's slower calculating it this way, but you can take advantage of the fact that PHP lets you increment letters in the same way as numbers, Perl style:
function excelColumnRange($number) {
$character = 'A';
while ($number > 1) {
++$character;
--$number;
}
return $character;
}
var_dump(excelColumnRange(2));
var_dump(excelColumnRange(29));

Answer 2

here is the code which you are looking for :
<?php
$start = "A";
$max = 50;
$result = array();
for($i=1; $i<=$max; $i++) {
$result[$i] = $start++;
}
print_r($result);
?>
Ref: http://www.xpertdeveloper.com/2011/01/php-strings-unusual-behaviour/

Answer 3

This should work for you:
Even without any loops. First I calculate how many times the alphabet (26) goes into the number. With this I define how many times it has to str_repleat() A. Then I simply subtract this number and calculate the number in the alphabet with the number which is left.
<?php
function numberToLetter($number) {
$fullSets = (($num = floor(($number-1) / 26)) < 0 ? 0 : $num);
return str_repeat("A", $fullSets) . (($v = ($number-$fullSets*26)) > 0 ? chr($v+64) : "");
}
echo numberToLetter(53);
?>
output:
AAA