Dear monks,

I would like to describe my problem with some sample codes below.

my %Hash;
$Hash{'2012'}{'Jan'}{'13th'} = 1; # set 13th Jan 2012 to true
$Hash{'2012'}{'Feb'}{'10th'} = 1; # set 10th Feb 2012 to true

if ($Hash{'2013'}{'Oct'}{'11th'}{'1AM'}{'30Min'}) {
   # if so, do something
}
## The if statement sets $Hash{'2013'}{'Oct'}{'11th'} to a hash ref
## which is undesirable.
## What I want is not to create $Hash{'2013'} at all.

## Later on if I check 
if ($Hash{'2013'}{'Oct'}{'11th'}) {
  ## I will end up here . . .
  ## I only want to be here if I set
  ## $Hash{'2013'}{'Oct'}{'11th'} = 1 explicitly.
}

[download]

The problem is with the 'if ($Hash{'2013'}{'Oct'}{'11th'}{'1AM'}{'30Min'})' statement which creates $Hash{'2013'}{'Oct'}{'11th'}{'1AM'} as a hash ref. Is there any way to check the existence of a nested hash key without creating the parent hash keys? I can change the if statement to the one below but it looks clumsy . . .

if ($Hash{'2013'} && $Hash{'2013'}{'Oct'} && $Hash{'2013'}{'Oct'}{'11t
+h'} && $Hash{'2013'}{'Oct'}{'11th'}{'1AM'} && $Hash{'2013'}{'Oct'}{'1
+1th'}{'1AM'}{'30Min'}) {
 # do something here
}

[download]

In reply to Undesirable parent hash keys by sophate

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