Simple List Picker

Simple List Picker

A ComfyUI node that takes a list and an index and returns the item at that index.

That is the whole node. It exists because the obvious way to write it is subtly wrong, and the wrong version fails in a way that looks like the index being ignored.

Install

git clone https://github.com/jmtoball/comfyui-simple-list-picker.git

into ComfyUI/custom_nodes/ and restart. No dependencies.

Use

Create List  ──list──▶  Simple List Picker  ──item──▶  (anything)
Primitive Int ─index──▶

| input | | |---|---| | items | Any list output — Create List, or anything with OUTPUT_IS_LIST | | index | Negative counts from the end, as in Python | | mode | wrap (default), clamp, or error when the index is out of range |

| output | | |---|---| | item | The value at that index, of whatever type went in | | resolved_index | Where the index actually landed after wrap/clamp | | count | How many items the list held |

One item per queued job

The index widget carries control_after_generate. Set it to increment and it advances once per queued run, exactly as a seed does:

1. Put your prompts in a Create List.
2. Wire Simple List Picker between it and your text input.
3. Set index to 0 and its control to increment.
4. Queue with a batch count of N.

Each job takes the next prompt. With mode: wrap you can queue more jobs than you have prompts and it cycles.

Two things worth knowing: the index is a counter, not a queue, so nothing is consumed and re-running a job repeats its prompt; and the counter keeps climbing between sessions, so reset it by hand when you want to start over.

Why this needs to be its own node

ComfyUI has two different things that both get called a list:

• a list output — a socket flagged OUTPUT_IS_LIST, which is what Create List produces. Downstream nodes never receive the list. The executor runs them once per item and collects the results.
• a Python list received whole, which only happens when the receiving node declares INPUT_IS_LIST = True.

A generic "index into any input" node that does not declare INPUT_IS_LIST is therefore invoked once per element and returns each of them in turn. From the graph it looks as though the index is being ignored — the node is working exactly as written, on one item at a time, having never seen a list.

This node declares INPUT_IS_LIST, so it receives every item and returns one. The consequence is that all its inputs arrive wrapped, index included: a widget set to 3 shows up as [3]. Unwrapping those is the other half of the job, and getting it wrong turns the index into a list and the arithmetic into something else.

Development

pip install pytest ruff
ruff check .
pytest tests

CI runs both on Python 3.10, 3.11 and 3.12.

License

MIT