if (55 < $age && $age <= 60) ...
####
foreach (keys %insitution_table)
{
$institution_table{$_}{ages}[$age/5]++;
}
##
##
my $sample = $insitution_table{$_}{ages}[60/5];
##
##
my %valid_institutions = map { $_ => $_ } (
$hospital1,
$hospital2,
);
# ...
my $key = $institution
&& ($valid_institution{lc($institution)} || "other")
|| "unaffiliated";
$institution_table{$key}{count}++;
##
##
my %foo = map { $_ => 1 } qw[ foo bar baz ];
my $foo = 'foo';
print "\$foo is in the list\n" if ($foo{$foo});
##
##
... $valid_institution{lc($institution)} || ...
##
##
... $valid_institution{lc($institution)} && lc($institution) || ...