StringToolsConcatList

Concatenation, but the parts arrive in one list

StringToolsConcat joins several separate text wires with a separator you wire in. StringToolsConcatList does the same job for the case where your parts already come as a list on a single text_list port - say, bundled by StringToolsStringsToList or produced by any other list-of-strings node.

The use case is the classic "tags from a list" pattern: instead of five separate text_0/text_1 wires, you have one list of tag strings, and you want them joined into a single comma-separated prompt line. Feed the list into text_list, wire a StringToolsString containing ", " into separator, and the node hands back one assembled string.

How it works

This is an INPUT_IS_LIST node: text_list arrives as a whole list on one port, gets flattened (nested lists are unwound), and every element is stringified and joined with the separator. Order is preserved - first element first, last element last.

The separator is where the differences from its sibling show up:

• It's a force-input port, same as StringToolsConcat - you wire a string node into it rather than typing into a box. Connect a StringToolsString with ", ", "\n", " + ", whatever.
• If you leave it unconnected, it defaults to a newline ("\n"). Note that contrast: plain StringToolsConcat defaults to no separator (parts get smushed together), while this one quietly newline-joins. It's a sensible default for "list of prompt lines," but it surprises people who expected an empty join.

The inputs that matter

• text_list (STRING list) - the strings to join, in order.
• separator (STRING, optional) - what goes between elements. Unwired means newlines.

Output is a single STRING - the joined result, ready for a CLIP encode or wherever assembled text goes.

Installing it

One-pack install. ComfyUI Manager: "Install Custom Nodes", search ComfyUI String Tools (repo Taremin/comfyui-string-tools), install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/Taremin/comfyui-string-tools

Restart fully. No pip dependencies, no model downloads - stdlib Python plus a small JS file, MIT license, release 0.0.7.

Gotchas

• An empty list returns an empty string. If your upstream bundler is half-disconnected, the output silently collapses to nothing.
• Remember the newline default. If your joined output looks like a block of separate lines, that's the unwired separator doing its job. Wire a separator string in to change it.
• Single string into text_list won't fly - a list port wants a list. Bundle with StringToolsStringsToList first.
• Newline characters from the source strings are preserved as-is; a "\n" inside one element stays there even if your separator is a comma.