in reply to Re^2: min and max in a hash of hash
in thread min and max in a hash of hash

That will give you the minimum value for each year. The OP wanted just the overall minimum. If he doesn't need the y/m of the minimum, then he could use 

use List::Util qw( min max );

my $min = min map { min values %{$Year{$_}} } keys %Year;
my $max = max map { max values %{$Year{$_}} } keys %Year;

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Update: Fixed s/values/keys/ as per reply.

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Re^4: min and max in a hash of hash
by pRaNaV (Novice) on Jan 22, 2012 at 12:02 UTC

    hi, slight correction

    use List::Util qw( min max );

my $min = min map { min values %{$Year{$_}} } keys %Year;
my $max = max map { max values %{$Year{$_}} } keys %Year;

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Re^4: min and max in a hash of hash
by Anonymous Monk on Jul 17, 2014 at 19:52 UTC
    I believe he was interested in both the year and month as am I. I currently have the same issue. I have the same data structure using a hash of hash. I would like to report for each year, the month and value of the min and max value. How can your existing example be modified to accommodate this?
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      Here's an example of how to accomplish this: 

      use List::Util qw/min max/;

my %results = map {
    my $year_ref = $data{$_};
    my $min = min values %$year_ref;
    my $max = max values %$year_ref;
    my @min_months = grep { $year_ref->{$_} == $min } keys %$year_ref;
    my @max_months = grep { $year_ref->{$_} == $max } keys %$year_ref;

    $_ => {
        "min"           => $min,
        "max"           => $max,
        "min_months"    => \@min_months,
        "max_months"    => \@max_months
    }
} keys %data;

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      Note that this takes into account the possibility of there being several months that each have the minimum/maximum value; if your data for each year/month is guaranteed to be distinct, you could drop that and replace \@min_months with $min_months[0] and \@max_months with $max_months[0], respectively.

      There may well be a more concise way of doing this, too, but neither List::Util nor List::MoreUtils appears to contain versions of min and max that operate on key/value pairs (pairmin and pairmax? Now there'd be a worthwhile addition to these modules.)

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