String from List

ComfyUI hands you lists all the time - a batch of filenames, a list of prompts, a stack of wildcard expansions - but the core nodes are weirdly thin on "give me item number three." String from List fills that gap: feed it a list of strings and an index, and it returns the item at that position. The useful part is the wrap-around: indexes beyond the end of the list loop back to the start instead of erroring, so you can step through a list indefinitely without ever hitting a crash.

The mechanism is small but thoughtful. The list_input is a string (which can be a list of strings), the index is an integer that supports wrap-around, and the outputs tell you everything you might need:

• list item - the selected string, returned as a list (so downstream list handling just works).
• size - the number of items in the list. Handy for bounds logic or iterating.
• wraps - how many times the index wrapped around the end. Zero means you're inside the list; a positive value means you looped.

That wraps output is the quiet gem - it lets downstream logic know you've cycled back to the start, which matters if you're using this for looping through a fixed set of prompts and want a "new lap" signal to trigger something else.

Where it fits

Two classic uses. First, cycling: drive index from a counter or seed and step through a list of prompts or negative blocks, one per run. Second, batch selection: pick a specific item out of a generated list without splitting anything yourself. Because the output is a list-type string, it chains into any node expecting a list of strings.

Installing it

Part of ComfyUI_Eclipse, no dependencies:

git clone https://github.com/r-vage/ComfyUI_Eclipse custom_nodes/ComfyUI_Eclipse

Or ComfyUI Manager → search "ComfyUI_Eclipse" → install and restart.

Gotchas

The wrap-around is a feature, but it's also the thing that will surprise you: an out-of-range index won't fail, it'll silently wrap - so if you expected an error to catch a bug, you won't get one. That's exactly why the wraps output exists; check it if "why is this the same item again?" ever confuses you. And remember the list comes from list_input at execute time, so it's a snapshot, not live. Pack note: pre-v4.0.0 RvTools-era node IDs need the migration tool on old workflows; fresh ones load fine.