This question has been asked so many times... ;-(

You don't want to do this. It is dangerous. See Dominus's expalnations on Why it's stupid to 'use a variable as a variable name'.

If you don't know the name of the array, then use a hash:

#!/bin/perl -w
use strict;

my %tmp;

while( my $tmp=<DATA>)
  { if( $tmp=~ /^(.+)(\d+)$/)
    { $tmp{$1}->[$2]= 'foo'; # don't you love auto-vivification?
    }
  }

__DATA__
foo2
foo5
foo0
bar
bar2
bar1
foo3
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