String Index Selector

String Index Selector is the pack's founding node - the README describes it as the original use case the whole thing was built around. The scenario: some node hands you a comma-separated string like "10,25,42,100" and you want one specific value out of it, typically inside a loop where the loop index tells you which one. This node splits the string, grabs the Nth item, and casts it to a real type so it plugs straight into an INT or FLOAT input.

The original use case was VHS/frame-extraction style workflows: a video node produces a list of frame numbers as text, and this node picks the frame for the current loop iteration so Save Image writes frame_42.png instead of a constant. It's the difference between "I can only process frame 1" and "I can walk the whole list."

How it works

It splits text on delimiter (default ,), strips whitespace from each item, and picks the item at index. Escape sequences are honored, so you can type \n in the delimiter field to split on actual newlines. Then output_type casts the result: STRING, INT, or FLOAT. So:

text: "10,25,42,100", delimiter: ",", index: 2, output_type: INT
→ 42 as an integer

The zero_indexed toggle (default true) decides whether index 0 is the first item - flip it for 1-based counting. Out-of-range indexes return None plus the item count rather than crashing.

Inputs and outputs

• text (STRING) - the delimited string.
• delimiter (STRING, default ,) - what to split on.
• index (INT, 0–10000) - which item to take.
• strip_whitespace (BOOLEAN, default true) - trim each item.
• output_type (STRING / INT / FLOAT) - the cast to apply.
• zero_indexed (BOOLEAN, optional, default true).

Outputs: selected_item (*) and item_count (INT).

Where it fits

Loop workflows are the home turf - wire the loop counter into index, get a different value each pass. It also pairs with its own pack: String Splitter parses the whole string into a typed list when you need the items together, List Index Selector does the same job on an already-built list, and String Joiner reverses the process when you need to serialize.

Installing it

It's in ComfyUI-JK-TextTools. ComfyUI Manager → search "JK-TextTools" → install, or:

cd ComfyUI/custom_nodes
git clone https://github.com/Nakamura2828/ComfyUI-JK-TextTools.git

Restart ComfyUI. No models, no extra pip packages - pure Python string handling.

Gotchas

The type cast is the sharp edge: output_type: INT on an item like "cat" raises a ValueError and the node fails loudly. Keep INT/FLOAT for data you're sure is numeric. And remember None comes back silently on out-of-range indexes - if a node downstream starts complaining about a * value, check that your index is actually inside item_count.