It sounds to me like you need a different data structure, a HoA (Hash of Array). This is a hash key that is associated with a list of many key values. This is a more "natural" (meaning more Perl way) for what you are doing.
#!/usr/bin/perl -w
use strict;

my %hash;

while (<DATA>)
{
  my($id,$value)=split;
  push @{$hash{$id}}, $value;
}

foreach my $id (sort{$a<=>$b} keys (%hash))
{
  print "id=$id values=@{$hash{$id}}\n";
}
#prints:
#id=1 values=3 2 10
#id=2 values=5 6
#id=3 values=4
__DATA__
1 3
1 2
1 10
2 5
2 6
3 4

[download]
The "tricky" syntax part is that "extra {}" in @{$hash{$id}} is necessary when using a sub sub-scripted variable (ie just @$hash{$id} won't work! The extra {} tells @ what to operate upon.

I don't know if this is some sort of homework problem?

In reply to Re: array of arrays by Marshall
in thread array of arrays by Anonymous Monk

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