Dear perl monks, I have used the essence of the code below for a while and first programmed it without thinking much about it. Now I am working through some structured perl tutorial and cannot find anything similar. Can anyone explain the notation $bin[$variable][$othervariable]? Thanks in advance, Annemarie 
#! /usr/bin/perl

$template="A2x2A3";

for $mag (50..90){
  $abumax[$mag]=1;
 for $abu (1..100){
  $bin[$mag][$abu]=0;
  }
 }

while (<>){
 ($mag,$abu)=unpack($template,$_);
 $bin[$mag][$abu]++;
 $abumax[$mag]=$abu if ($abu >$abumax[$mag]);
 }

for $mag (50..90){
 for $abu (1..$abumax[$mag]){
  if ($bin[$mag][$abu] !=0){
   printf"%2s %3s %3s\n", $mag, $abu, $bin[$mag][$abu];
 }
}
}

[download]
A sample testfile looks like this: 
50  1
50  2
53  5
54  2
50  2
53  5
54  2
50  2
53  5
54  2
64  5

[download]
The output looks like this: 
50   1   1
50   2   3
53   5   3
54   2   3
64   5   1

[download]

In reply to Counting frequency of occurrence - what am I doing? by Annemarie

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