complete deletion from hash

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

hi all,

i have an hash like this,

Testcase => 
{'comp' 
   => {'cmd' 
        => {'tc1' 
            => {platform_type => 'all',
                testsuite_type => 'all',
                view => 'private'},
            'tc2' 
            => {platform_type => 'all',
                testsuite_type => 'all',
                view => 'private'}
           }
      }
}
[download]

I delete a key/ value pair in the hash like this,

delete $hoh{$comp}{$cmd}{$tc1};
[download]

But when the value for a key becomes empty, i need to delete that also. How do i delete the key also?
After deleting both 'tc1' and 'tc2' key/value pair, the hash looks like,

Testcase => 
{'comp' 
   => {'cmd' 
        => {}
      }
}
[download]

But actually for "cmd", value is empty. So I would like to remove that. And obviously, "comp" value is also empty, so that also needs to be removed.

thanks
rsennat

Comment on complete deletion from hash Select or Download Code

Replies are listed 'Best First'.
Re: complete deletion from hash by wfsp (Abbot) on Nov 24, 2005 at 10:39 UTC
You could use the `keys` function to test for the existance of any keys. #!/usr/bin/perl use strict; use warnings; use Data::Dumper; my $h = { 'comp' => { 'cmd' => { 'tc1' => { platform_type => 'all', testsuite_type => 'all', view => 'private' }, 'tc2' => { platform_type => 'all', testsuite_type => 'all', view => 'private'} } } }; delete $h->{comp}{cmd}{tc1}; delete $h->{comp}{cmd}{tc2}; unless (keys %{$h->{comp}{cmd}}){ delete $h->{comp}{cmd}; } unless (keys %{$h->{comp}}){ delete $h->{comp}; } print Dumper($h); __DATA__ ---------- Capture Output ---------- > "c:\perl\bin\perl.exe" _new.pl $VAR1 = {}; > Terminated with exit code 0. [download]	[reply] [d/l] [select]
Re^2: complete deletion from hash by inman (Curate) on Nov 24, 2005 at 10:51 UTC
The following worked in scalar context without using keys to give list context. An empty hash gives 0 in scalar context. `delete $hoh{Testcase}{comp}{cmd} unless %{$hoh{Testcase}{comp}{cmd}}; delete $hoh{Testcase}{comp} unless %{$hoh{Testcase}{comp}};` [download]	[reply] [d/l]
Re^2: complete deletion from hash by rsennat (Beadle) on Nov 24, 2005 at 10:44 UTC
oh. thats gr8!!! thanks a lot	[reply]
Re: complete deletion from hash by Perl Mouse (Chaplain) on Nov 24, 2005 at 10:54 UTC
Here's a recursive sub that does that: `sub rec_del; sub rec_del { my ($hash, @keys) = @_; return unless @keys; my $key = shift @keys; return unless exists $$hash{$key}; if (@keys) { rec_del $$hash{$key}, @keys; delete $$hash{$key} unless %{$$hash{$key}}; } else { delete $$hash{$key} } }` [download] Call it as `rec_del $hoh, $comp, $cmd, $tc1`. `Perl --((8:>*`	[reply] [d/l] [select]