Size of hash of hashes

AndreasL has asked for the wisdom of the Perl Monks concerning the following question:

Hi all,
I have a question to scalar and hash of hashes, I thought I could find the size of the "number" level like this. But the answers in DB<8> and DB<10> are suprising for me.
And DB<12> confuses me even more.

-> perl -de 1 

Loading DB routines from perl5db.pl version 1.19
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

main::(-e:1):   1
  DB<1> $a{'a'}{0}=0

  DB<2> print scalar %{$a{'a'}}
1/8
  DB<3> $a{'a'}{1}=0           

  DB<4> print scalar %{$a{'a'}}
2/8
  DB<5> $a{'a'}{2}=0           

  DB<6> print scalar %{$a{'a'}}
3/8
  DB<7> $a{'a'}{3}=0           

  DB<8> print scalar %{$a{'a'}}
3/8
  DB<9> $a{'a'}{4}=0           

  DB<10> print scalar %{$a{'a'}}
3/8
  DB<11> $a{'a'}{5}=0           

  DB<12> print scalar %{$a{'a'}}
4/8
[download]

How could I get the size of this? Any hints?

Thanks Andreas

Comment on Size of hash of hashes Download Code

Replies are listed 'Best First'.
Re: Size of hash of hashes by kvale (Monsignor) on Feb 26, 2004 at 23:49 UTC
To get the number of hash elements, use the `keys` function: `$a{a}{$_}++ foreach (0..5); print scalar keys %{ $a{a} };` [download] -Mark	[reply] [d/l] [select]
Re: Re: Size of hash of hashes by AndreasL (Scribe) on Feb 26, 2004 at 23:54 UTC
Thanks Andreas	[reply]
Re: Size of hash of hashes by Roger (Parson) on Feb 26, 2004 at 23:59 UTC
1/8 means 1 bucket used out of 8 allocated. `for (0..15) { $a{'a'}{$_} = 0; print scalar %{$a{'a'}}, "\n"; }` [download] And the output is - `1/8 2/8 3/8 3/8 3/8 4/8 5/8 6/8 8/16 9/16 10/16 11/16 11/16 11/16 12/16 15/32` [download] If you want to find out the actual size, flatten into a list first. `print scalar @{[%{$a{'a'}}]}, "\n";` [download]	[reply] [d/l] [select]