I have the following hash of hashes: 
   my %switch_hash = (
           chrdex   => {
           DEX   => {
          '01-AUG-02'  => 1,
          '03-AUG-02'  => 3,
           }
              },
        uslcgb5e2sm       =>{
           Greensboro  => {
          '4-AUG-02'   => 1,
          '6-AUG-02'   => 2,
           }
        },
        uslecat25e1       => {
           'Atlanta II' => {
          '1-AUG-02'   => 1,
          '2-AUG-02'   => 3,
          '3-AUG-02'   => 1,
          '4-AUG-02'   => .25,
           }
        },
    );

$rhent = \%switch_hash;

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I want to do this: 
my @dates = ( keys %{(keys %{(keys %$rhent)})} );

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and I get this error: 
Can't use string ("3") as a HASH ref while "strict refs" in use at ./x
+cl3.pl line 301

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Can something like this be done to get the key containing the date from the final hash? NOTE: There is a reason for using a reference, but that is beyond the scope of this question.

In reply to using 'keys' recursively on a hash of hashes by gnu@perl

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