Question

I need to generate a sequence (or function to get a “next id”) with an alphanumeric incrementor.

The length of the string must be defineable, and the Characters must be 0-9, A-Z.

So for example, with a length of 3:

000
001
002
~
009
00A
00B
~
00Z
010
011
etc..

So I imagine the function might be used like this:

$code = '009'
$code = getNextAlphaNumeric($code);
ehco $code; // '00A'

I’m working on a solution to this myself, but curious if anyone has tackled this before and come up with a smarter / more robust solution than my own.

Does anyone have a nice solution to this problem?

Answer 1

Would something like base_convert work? Maybe along these lines (untested)

function getNextAlphaNumeric($code) {
   $base_ten = base_convert($code,36,10);
   return base_convert($base_ten+1,10,36);
}

The idea is that your codes are all really just a base 36 number, so you convert that base 36 number to base 10, add 1 to it, then convert it back to base 36 and return it.

EDIT: Just realized that there may be an arbitrary string length of the code, but this approach might still be doable — if you capture all the leading zeroes first, then strip them off, do the base 36 -> base 10 conversion, add one, and add back any needed leading zeroes …