Your best bet would be to use a hash for your root element, keyed on item_key, and then populate it by crawling over your list, adding base elements if the key doesn't exist yet and pushing your actions onto the appropriate array if it does. Details on dealing with hashes of hashes (HoH) and their friends can be found in perllol (and if you need it, basic dereferencing is here). Happy to help debug once you've cobbled some code together.

In reply to Re: Grouping an array of hashrefs by similar key values by kennethk
in thread Grouping an array of hashrefs by similar key values by perldj

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