From List Type Node Ovum

From List Type Node Ovum converts a plain Python list into a tuple, set, dict, or dict-from-pairs. It's the current, non-deprecated member of Ovum's converter trio, filed under ovum/lists/python - the home for nodes that think in actual Python lists rather than ComfyUI's batch-flavored ones.

The use case is the eternal one in a typed graph: the node you're feeding has opinions about container shape, and your list has different opinions. Want duplicates gone? Convert to a set. Want to look values up by key? Convert to a dict. Want an immutable record you can carry through a loop? Convert to a tuple. Instead of reaching for a scripting node, you drop in a converter and flip one dropdown.

Inputs and outputs

• py_list (LIST) - the source list. Must genuinely be a list; otherwise it raises a clear "Input must be a Python list" error.
• target_type - the dropdown:
  • list - identity pass-through
  • tuple - (a, b, c, ...)
  • set - deduplicated
  • dict - index→value: [a, b, c] → {0: a, 1: b, 2: c}
  • dict_pairs - expects [key, value] pairs and builds a real keyed dict

Output: a single * socket. The node is marked as an output node, so it can sit at the end of a chain and you can read its converted value in the UI.

Choosing among the three siblings

The pack ships three converters that look identical, and picking the right one is the actual decision here:

• From List Type Node Ovum (this one) - ovum/lists/python, for genuine Python-list workflows
• From Batch Type Node Ovum - ovum/lists/comfy, the batch-aware flavor for when you're operating on ComfyUI's list/batch sockets
• From List Type Node - ovum/lists/any, deprecated (display name ends in DEPRECATED(batch)), kept only for legacy workflows

Rule of thumb: match the socket family you're connected to. If you're in the middle of a list-building chain of pure Python lists - say, feeding a ForeachListBegin loop or a string-list editor - this is your node. If you're near batch-oriented sockets, use the comfy variant. Either way, don't use the deprecated one.

Installing it

Part of sfinktah/comfy-ovum:

cd ComfyUI/custom_nodes
git clone https://github.com/sfinktah/comfy-ovum

or search comfy-ovum in ComfyUI Manager, then restart. No models, no heavy deps.

Gotchas

dict_pairs is the strict one - every element must be a two-element list or tuple or it raises a descriptive error. And a set conversion is destructive of order and duplicates, so only reach for it when neither matters. One more: this node expects a list input. Feed it a tuple and it'll complain, because the node's own contract is list-in - convert first if you're starting from a tuple.