switch/case

Some workflows need "pick one of several options based on a number" - a computed index that decides between three prompt styles, two models, four resolutions. You could build that with a pile of if/else nodes. Or you could use switch/case, which is exactly Python's switch-style selection: feed it an index, get back the matching value.

It's one of the flow-control nodes in Basic data handling, StableLlama's dependency-free utility pack. And yes - there's a catch up front. The author's own description carries a note: this version of the node will most likely be deprecated in the future. The pack is actively evolving its control-flow family, so learn the pattern here but don't be shocked if the newer flow-select nodes are what replace it.

How it works

You give it a select integer and a list of case inputs (case_0, case_1, ...), with a default as a safety net. It returns the case matching your index; if the index is out of range, you get default. Under the hood the case inputs are dynamic (you add more with a "+" button), and the node uses lazy evaluation - it only asks ComfyUI to compute the one case you actually selected, not all of them. That's a real efficiency win when your cases are expensive (a whole model load, say): the unselected branches never even evaluate.

The inputs and the output

• select (INT, default 0, min 0) - the index. Wire it from a counter, a random node, a comparison, anything that produces an int. Index 0 = case_0, index 1 = case_1, and so on.
• case_0 (ANY, dynamic) - the first option. Add more cases with "+". Values can be prompts, numbers, conditioning - whatever the downstream expects.
• default (ANY, optional) - returned when select is out of range. Leave it unconnected and out-of-range returns None, which is usually a bug you want to catch, not a silent pass.
• result (output, ANY) - the chosen value.

Installing it

Install Basic data handling via ComfyUI Manager (search "Basic data handling"), or:

cd ComfyUI/custom_nodes
git clone https://github.com/StableLlama/ComfyUI-basic_data_handling

Restart ComfyUI. No Python dependencies, no models to download - one of the cleanest installs in the ecosystem.

Troubleshooting

• "It always picks case 0." Then select is 0 - check what's actually wired into it. If select came from a node whose output is a float or a string, ComfyUI may be coercing it in a way you didn't expect (a "1" string and an 1 int are different). Cast it to INT explicitly with the pack's to INT node before it reaches select.
• "Out of range gives me garbage." You left default unconnected, so you got None downstream and it did something weird. Always connect a default when you can't guarantee the index range.
• "I want a condition, not an index." Then you want if/elif/else, which branches on booleans. SwitchCase is for the "choose by number" case specifically - and remember it's flagged for future deprecation, so if you're building something long-lived, keep an eye on the pack's changelog.