jz String Picker

Every workflow eventually needs "one of these, please" - a random prompt from a bank of styles, a random negative template, a random watermark text. ComfyUI has a dozen nodes for that, and they mostly fall into one of two traps: random picks you can't reproduce, or index picks you have to babysit. jz String Picker splits the difference. You give it a list of strings, and it picks one either randomly from a seed you control, or deterministically by an index that wraps around the list.

It's the sibling of jz Choice in the jz/util menu, and the two are easy to mix up. Choice asks "which named option did you want?" and validates the answer. String Picker asks "give me one" - you pick the strategy (random or index), not the value. If you want to sweep through every entry in order on successive runs, this is the node; if you want to hard-select a named entry that must survive list edits, use Choice.

How it works

items is a multiline STRING, one entry per line (the separator dropdown lets you switch to comma, semicolon, or pipe). Blank lines are stripped and an empty list raises, so a typo'd list fails instead of silently picking from nothing.

The mode widget is where the real behavior lives:

• random - picks using a seeded RNG, so the same seed always gives the same pick. The seed widget has a control_after_generate control like a KSampler's; set it to "randomize" and the pick re-rolls on every queue, or lock it for reproducibility. This is the same control-after-generate mechanism that trips people up on sampler seeds - the number shown is what runs next, so if you find a good pick, flip the control to "fixed" before you change anything else.
• index - returns items[index % count]. Because it wraps around, you can feed it an incrementing counter and step through the whole list one run at a time, forever, without ever going out of bounds. That's the sneaky-useful mode for batch sweeps.

The outputs

You get three, and two of them matter more than people expect:

• text - the picked string, ready to wire into a prompt or filename prefix.
• picked_index - which position was picked. Feed this to an "get item at index" node downstream and the rest of the graph can stay in sync with the pick.
• count - how many entries the list had. Handy for math like "run exactly once per entry" without hardcoding the list length.

Installing it

Same pack, same one-liner:

cd ComfyUI/custom_nodes
git clone https://github.com/j-zhang19/comfyui-jz

Restart ComfyUI (or install via Manager by searching "comfyui-jz"), and it appears under jz/util. Dependencies are just requests, pillow, and numpy - nothing heavy, no models.

Common issues

The usual beginner snag is expecting a random pick to stay the same after you re-run, then discovering the seed widget was set to randomize. Either is fine - just know which you're in. Second gotcha: entries are whitespace-stripped, so don't rely on leading/trailing spaces to distinguish two options; the node will silently collapse them into the same entry. And remember the empty-list raise: if the node starts erroring, check that your list actually parsed (wrong separator is the classic culprit).

It's a small personal-pack utility with no community lore to speak of - the author's README is the only documentation - but for seeded random picks and wrap-around index sweeps, it's genuinely the cleanest version of this pattern I've used.