How can I use a database kind of text file?

Hey all, I am receiving a String from a Telnet Server - next I am getting the Number of the Variable which is in the String so I add

void LedLightup(){
  
  char hundreds = StringAnswer.charAt(10);
  char tens = StringAnswer.charAt(11);
  char ones = StringAnswer.charAt(12);
  String StringNumber;
  StringNumber += hundreds;
  StringNumber += tens;
  StringNumber += ones;
  if (StringAnswer.charAt(14) = 0) {
  int LedOnOff = 0;
  }
  if (StringAnswer.charAt(14) != 0) {
  int LedOnOff = 1;
  }
  StringAnswer = "";
  counter = 0;

}

Now I have like 400 Leds which will be multiplexed by many AS1106 (like the MAX 7221). So I have the number of the variable: StringNumber. I have the Ethernet Shield and can connect a SD card - I think that would be the best way to look up all the lc numbers, and LED addresses on the AS1106 because the program is getting quite big if I implement all that in If- statements. Now - how do I look up those numbers specific to the variable I receive via ethernet. So if I get like StringNumber = 100 there should be the possibility to look up that the needed LED is in the first column first row - and therefor just say “char LedAddress = something in the file”

i hope you understand what I mean - quite difficult to explain…

Ma®c

convert stringnumber to an int and use it as an index of an array (that may be located on sdCARD)