Sort of similar to ikegami's solution, but I calculate the sum on the fly instead of as a post-processing step. 
my %values;

while (<DATA>) {
    my ($col, $val) = split;
    # store the sum and number of occurrences in a hashref
    $values{$col}[0] += $val;
    $values{$col}[1]++;
}

for my $col (sort keys %values) {
    print "$col ", $values{$col}[0] / $values{$col}[1], "\n";
}

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In reply to Re: HOW to calculate the column data by lostjimmy
in thread HOW to calculate the column data by xbmy

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