ComfyUI-List-Utils

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Primitive ComfyUI custom nodes for working with ComfyUI List processing, raw Python list values, and typed value bundles.

This extension uses three similar-looking but very different container concepts:

| Name | Meaning | Main Use | | --- | --- | --- | | List | ComfyUI's official Data list / List processing | Run downstream nodes once per item | | PyList | A raw Python list value | Keep an array as one value and manipulate it directly | | Pack | A List-Utils typed container | Bundle values of different ComfyUI types and restore them later |

Installation

Clone this repository into ComfyUI/custom_nodes, then restart ComfyUI.

git clone https://github.com/godmt/ComfyUI-List-Utils.git

Nodes are added under the list_utils category.

GUI Help

The nodes include inline help for the ComfyUI interface:

• Node-level descriptions explain what each node is for.
• Inputs and widgets include tooltips for expected values.
• Outputs include tooltips for what they return.
• Dynamic inputs created by Create List, Create PyList, Merge List, Merge PyList, Pack, and Exec also receive tooltips.

Choosing List, PyList, Or Pack

List

List means ComfyUI List processing. Use it when you want ComfyUI to process several prompts, seeds, images, paths, or other values one item at a time.

List-Utils List nodes use ComfyUI's OUTPUT_IS_LIST / INPUT_IS_LIST behavior. The output socket type remains the original item type, such as STRING, INT, or IMAGE.

Common uses:

• Send several strings downstream one by one
• Generate sequential seeds with Create Range
• Enumerate files with List Dir
• Extract or slice a ComfyUI List with List: Get By Index / List: Slice

PyList

PyList is a raw Python list passed as one ComfyUI value. It does not trigger ComfyUI List processing by itself.

Common uses:

• Keep strings, numbers, paths, or other values as one array
• Use Python-style index, slice, merge, or cast operations
• Convert a ComfyUI List into one Python list with List To PyList
• Convert a Python list back into ComfyUI List processing with PyList To List

Pack

Pack bundles multiple values into one PACK socket while preserving each input's name, type, and value.

Use Pack / Unpack when you need to pass different ComfyUI types together. For example, a single Pack can carry MODEL, CLIP, VAE, CONDITIONING, and IMAGE values, then restore them as separate typed outputs later.

Typical Workflows

Split Text And Process Each Item

1. Put multiline or delimiter-separated text into Split String.
2. Use the STRING output when you want ComfyUI List processing.
3. Use the PYLIST output when you want one raw Python list value.
4. Use length when you need the item count.

Convert PyList To ComfyUI List

1. Create a PYLIST with Create PyList, Split String, Create Range, or a similar node.
2. Connect it to PyList To List.
3. The output becomes a ComfyUI List-processing output and downstream nodes run once per item.

Use List To PyList for the opposite direction, when you want to collect a ComfyUI List into one Python list value.

Bundle Different Types

1. Connect values to Pack.
2. Connecting the last empty socket adds another input automatically.
3. Connect Pack to Unpack.
4. Unpack creates outputs matching the input count and types from Pack.

Unpack can determine its output types after being connected to Pack once. It can also trace through some intermediate nodes such as switch-style nodes or Anything Everywhere-style nodes when the upstream Pack is discoverable.

Nodes

Create / Generate

| Node | Output | Description | | --- | --- | --- | | Split String | STRING List, PYLIST, length | Splits text by delimiter and/or lines. Empty items are removed. | | Create List | List | Creates a ComfyUI List from multiple dynamic inputs. | | Create PyList | PYLIST | Creates a raw Python list value from multiple dynamic inputs. | | Create Range | INT List, PYLIST, length | Creates integer values with Python range(start, stop, step). | | Create Arange | FLOAT List, PYLIST, length | Creates values with numpy.arange(start, stop, step). | | Create Linspace | FLOAT List, PYLIST, length | Creates evenly spaced values with numpy.linspace(start, stop, num). | | List Dir | STRING List, PYLIST, length | Lists path matches from a folder using a glob pattern. |

Merge / Convert

| Node | Output | Description | | --- | --- | --- | | Merge List | List | Concatenates multiple ComfyUI Lists. | | Merge PyList | PYLIST | Concatenates multiple PyLists. | | List To PyList | PYLIST | Collects a ComfyUI List into one Python list value. | | PyList To List | List | Expands a PyList into ComfyUI List processing. |

Get / Slice

| Node | Output | Description | | --- | --- | --- | | List: Get By Index | item | Reads one item from a ComfyUI List by index. | | PyList: Get By Index | item | Reads one item from a PyList by index. | | List: Slice | List | Slices a ComfyUI List with Python-style start:end. | | PyList: Slice | PYLIST | Slices a PyList with Python-style start:end. |

Pack / Unpack

| Node | Output | Description | | --- | --- | --- | | Pack | PACK | Bundles multiple inputs with their names, types, and values. | | Unpack | original types | Restores values from a Pack. Output types change dynamically to match the connected Pack. |

Inspect / Utility

| Node | Output | Description | | --- | --- | --- | | Get Length | INT | Returns len(value) and displays it on the node. | | Get Shape | width, height, PyList_size, channels | Reads shape information from IMAGE, LATENT, or MASK. | | Any To Dict | DICT, str() | Converts an object to a dict when possible and also returns str(value). | | Get Widgets Values | PYLIST | Reads and displays widget values from the connected upstream node. | | Any Cast | selected type | Relabels a value as a selected type and converts basic scalar types when possible. | | PyList Item Cast | PYLIST | Converts each item inside a PyList to STRING, INT, FLOAT, BOOLEAN, and similar types. | | Exec | any | Runs Python code using inputs as x[0], x[1], ... and returns result. |

Dynamic Inputs

These nodes add input sockets dynamically:

• Create List
• Create PyList
• Merge List
• Merge PyList
• Pack
• Exec

Connect the last empty socket to add the next socket. Disconnecting sockets cleans up unused inputs.

Create List / Merge List adapt their output type from the first connected input. Pack preserves the type of each input separately.

Notes

• List and PyList are different. If a connection does not work, or execution is not happening in the expected mode, use List To PyList or PyList To List.
• List: Get By Index and PyList: Get By Index return None when the index is out of range.
• Slices use Python behavior: start:end does not include the item at end.
• Exec runs arbitrary Python code. Use it only in workflows you trust.

Example