Join Strings List

Sometimes you have a list of strings - tags from a splitter, batch names, wildcard picks - and what you actually want is one big text block you can stuff into a prompt or a filename. ZeugJoinStrList is the funnel: a list in, a single joined string out, with the separator of your choice.

What it is

ZeugJoinStrList lives in the zeug → Transform menu. Input strings is a list of STRINGs; input delimiter is a STRING that defaults to ",". One output, text. Give it ["cat", "girl", "lora"] with a ", " delimiter and you get "cat, girl, lora" back. It's the natural counterpart to ZeugSplitStrList - that node breaks text apart, this one puts it back together.

When you'd reach for it

• Turning a split/parsed list back into a comma-separated prompt or tag string.
• Flattening a batch of names into a single filename or label.
• Reassembling text that some other step deliberately broke up - round-tripping through ZeugSplitStrList and back with the same delimiter gets you the original string.

It's the list-flavored sibling of ZeugJoinStr (which only joins two strings). If you're working with lists of text at all, this is the one you'll actually keep in your toolbar.

How it works

Here's the mechanism detail worth understanding, because it affects how you wire it: the node declares INPUT_IS_LIST = True, so ComfyUI hands it every value on the strings input as a list. That's exactly what you want for the strings - but it also means the delimiter input arrives as a list, so the node takes the first element of the delimiter as the separator (delimiter[0], falling back to "," if it's empty).

Practically: connect a list output (like ZeugSplitStrList's strings) to the left side, type a delimiter in the widget, and it works as you'd hope. The subtlety only bites if you try to feed it a single string on the strings input - with INPUT_IS_LIST active, a plain string may not arrive the way you expect, so wire an actual list into it. An empty list yields an empty string rather than an error.

How to install it

Ships in comfyui-zeug (German for "gear" or "stuff"), a small GPL-3.0 pack by Adrian Schubek:

• ComfyUI Manager: search zeug in the Custom Nodes Manager, install ComfyUI-Zeug.
• Manual:

cd ComfyUI/custom_nodes
git clone https://github.com/adrianschubek/comfyui-zeug

Restart ComfyUI. Zero dependencies, no model downloads - only torch and ComfyUI's own modules, both already on your system.

Common issues

The big one is the list-input expectation above: people wire a single string in and get surprising results. Make sure the strings input is genuinely receiving a list (is_list output). If it is and the output still looks wrong, check the delimiter - an empty or single-character separator produces the concatenation you see.

Otherwise it's a dependable utility: list in, text out, no drama. Pair it with the splitter and you've got a two-node text pipeline for handling delimited data.