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. }