I have a pretty complicated (for me anyway) hash setup as shown in the example snippet below:

my %hash = ( 'A1' => { 
                               'B1' => 'Value',
                               'B2' => { 
                                        'C1' => [arrayitem1, 
                                                 arrayitem2,
                                                 arrayitem3,],

                                        'C2' => [arrayitem1, 
                                                 arrayitem2,
                                                 arrayitem3,],
                                       }
                              },
                     )
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What I want to do is check whether C1 or C2 exists. If it exists, I want to add another item to its array. If C1 or C2 does not exist, I want to create it as an array reference and add an item to its array.

At the moment my code looks something like this:

if (exists $hash{'A1'}{'B2'}{'C1'}) {
    push ( @{ $hash{'A1'}{'B2'}{'C1'}}, arrayitem4;
} else {
    $hash{'A1'}{'B2'} = {'C1' => [arrayitem1]};
}
[download]

The code doesn't work as I get various "Can't use string ("") as a HASH ref while "strict refs" in use" errors. I am getting very confused with all of the searching I have done to find the answer so would really appreciate it if someone could point me in the right direction.

The aim is that B2 would be a 'Test Results' key. The 'C' keys would refer to dates and then the arrays within them would be the data of the results (single line sentences) for that dates tests