comfy-math-strings

# ComfyUI math & strings Compute and assemble. Numbers in, numbers out; strings in, strings out; primitives that hold a constant; sliders that expose a tunable. The split: | Pack | Niche | |---|---| | `comfyui-kjnodes` | Primitives (BOOL / INT / Float / String / Multiline), SimpleCalculatorKJ, JoinStrings / JoinStringMulti, AppendStringsToList, Something/WidgetToString | | `comfyui_essentials` | Math hierarchy: SimpleMath / SimpleMathFloat / SimpleMathInt / SimpleMathDual (AST-based) | | `comfyui-custom-scripts` (pysssss) | `MathExpression` (full numpy + math imports), `StringFunction` (regex), `StringNodes` (split/case/trim) | | `comfyui-mxtoolkit` | `mxSeed`, `mxSlider`, `mxSlider2D` widget-driven values | | `bjornulf_custom_nodes` | `AnythingToText` / `AnythingToInt` / `AnythingToFloat`, TextReplace, CombineTexts, RandomLineFromInput | | `ComfyUI-Crystools` | `CBoolean` / `CInteger` / `CFloat` / `CText` / `CTextML` primitives, `CJsonFile` / `CJsonExtractor` / `CListAny` / `CListString` | | `comfyui-easy-use` | `easy string` / `easy int` / `easy float` identity nodes, `easy rangeInt` | | `comfyui-dream-project` | `DreamCalculation`, `DreamLinear`, sine/saw/triangle waves (animation-flavored, see "out of scope") | | `comfyui_yvann-nodes` | `FloatToInt`, `InvertFloats`, `MaskToFloat`, `FloatsToWeightsStrategy` | ## When to Use This Skill | Use this skill when... | Use instead when... | |---|---| | Computing a value or assembling a string in a workflow | Forming a boolean from that computation -> `comfy-conditionals` | | Converting between types (anything -> int/float/string) | Displaying the result -> `comfy-debug-preview` | ## Sources of truth - `custom_nodes/comfyui-kjnodes/nodes/nodes.py` — primitives, JoinStrings, Something/WidgetToString - `custom_nodes/comfyui_essentials/misc.py` — SimpleMath family - `custom_nodes/comfyui-custom-scripts/py/math_expression.py` — pysssss MathExpression - `custom_nodes/comfyui-mxtoolkit/` — slider widgets - `custom_nodes/ComfyUI-Crystools/crystools/nodes_*.py` — primitives, list helpers, JSON extractor - `custom_nodes/bjornulf_custom_nodes/` — Anything-To-* converters ## Math — which node? | Need | Best node | Why | |---|---|---| | Single FLOAT expression, simple ops | `SimpleMathFloat` (essentials) | Tight; one expression in, FLOAT out | | Single INT expression | `SimpleMathInt` | Same, INT result | | Multi-variable expression (a, b, c, d) — `(a+b)/c` etc. | `SimpleMath` | AST-based eval over named inputs; safe (no module imports) | | Two values, binary op (add/sub/mul/div/pow) | `SimpleMathDual` | Op picker widget | | Many variables (a–j) | `SimpleCalculatorKJ` (kjnodes) | Up to 10 named inputs | | Need numpy / math import — `np.sqrt`, `math.pi`, `np.clip`, etc. | `MathExpression` (pysssss) | Full module access, expression as string | | Animation curve over a frame index — linear ramp, sine wave | `DreamLinear`, `DreamSineWave` etc. | Built-in time/frame parameter | | Float ↔ INT | yvann `FloatToInt` (round/ceil/floor), `AnythingToInt` (bjornulf) | yvann has the rounding mode; bjornulf is the lenient any-input version | | Invert FLOAT (1−x or −x) | yvann `InvertFloats` | Mode picker | ### Math hierarchy in one line `SimpleMathFloat` < `SimpleMath` < `SimpleCalculatorKJ` < `MathExpression` Pick the simplest one that compiles. `MathExpression` (pysssss) is the "escape hatch" — full numpy + math imports, but a typo crashes the node with an opaque traceback. Use it only when AST-safe `SimpleMath` can't express what you need. ### `SimpleMath` syntax Variables: `a`, `b`, `c`, `d` (wire them as inputs). Operators: `+ - * / // % **`, parentheses, unary `-`. Functions: `min`, `max`, `abs`, `round`, `int`, `float`. ``` SimpleMath: expression: int(sqrt(a * 1000000 * b) / 8) * 8 a = megapixels b = aspect_ratio → width snapped to multiple of 8 ``` `SimpleMath` does NOT support `sqrt` natively — drop to `MathExpression` for that. Actual AST-safe set is limited; check the node source for the allowed call list. ### `MathExpression` syntax ``` import numpy as np import math # Expression — single line: int(math.sqrt(a * 1e6 * b) / 8) * 8 # Or use numpy: int(np.sqrt(a * 1e6 * b) / 8) * 8 ``` You write an expression string referencing input variable names that the node has registered. The node has `math` and `numpy` (as `np`) already imported. Errors surface as red node + traceback in the server log; nothing in the workflow UI. ## Strings — concat, replace, regex, split | Need | Best node | |---|---| | Concat a few strings with a delimiter | `JoinStrings` (kjnodes, 5-arg) | | Concat many | `JoinStringMulti` (kjnodes, dynamic N inputs) | | Concat 2 with no delimiter | `CombineTexts` (bjornulf) | | Find/replace literal | `TextReplace` (bjornulf) | | Find/replace regex | `StringFunction` (pysssss; regex_mode toggle) | | Pick random line from multiline | `RandomLineFromInput` (bjornulf) | | Split on delimiter | `StringNodes` (pysssss, operation picker) or `TextSplitByDelimiter` (mixlab) | | Add line numbers | `AddLineNumbers` (bjornulf) | | Tokenize | `DreamStringTokenizer` (dream-project, word-splitter) | | Build STRING from a list | `AppendStringsToList` (kjnodes) | ### Single-line vs multiline - `StringConstant` (kjnodes) — single line, no embedded newlines - `StringConstantMultiline` (kjnodes) — multiline, ideal for prompt bodies, JSON snippets, multi-clause text - `CText` (Crystools) — single line - `CTextML` (Crystools) — multiline Pick multiline for any string longer than ~80 chars or any string with embedded newlines. Single-line variants are for short labels and filenames. ### Regex via `StringFunction` ``` StringFunction (pysssss): action: replace regex_mode: ON text: "michael.jpg" find: "\.(png|jpg|jpeg|webp)$" replace: "" → "michael" ``` Useful for stripping extensions from a filename (the exact pattern we hit in the `comfy-image-utils` recipe set). Action picker also supports `append`, `replace`, `tidy tags` (the last one normalizes commas/spaces in tag lists for booru-style prompts). ## Type conversion `bjornulf`'s `AnythingTo*` family is the most lenient — it accepts literally any input type and produces the named scalar: | Node | Output | Notes | |---|---|---| | `AnythingToText` | STRING | `str(x)`-equivalent on any input | | `AnythingToInt` | INT | Coerces float / string / bool; raises if string isn't parseable | | `AnythingToFloat` | FLOAT | Same, FLOAT target | | `SomethingToString` (kjnodes) | STRING | Similar to bjornulf's AnythingToText | | `WidgetToString` (kjnodes) | STRING | Reads a specific widget by name from a target node — useful for surfacing arbitrary widget values into the data flow | `easy string` / `easy int` / `easy float` (easy-use) are **identity nodes** — they don't convert, just pass through. Their purpose is to expose a widget UI for a value that downstream nodes will consume; a debug-friendly handle. ## Primitives & sliders Constants, mxtoolkit sliders / `mxSeed`, `easy rangeInt`, and seed strategy: [references/primitives-and-sliders.md](references/primitives-and-sliders.md). ## JSON & lists (Crystools) Load / extract JSON and build lists (`CJsonFile`, `CJsonExtractor`, `CListAny`, `CListString`; no JSON write): [references/json-and-lists.md](references/json-and-lists.md). ## Recipes Worked graphs (resolution from megapixels + aspect, filename templating, tag lists from LoRA triggers, range-driven batch): [references/recipes.md](references/recipes.md). ## Gotchas When an expression, regex, or conversion misbehaves, check [references/gotchas.md](references/gotchas.md) — `SimpleMath` vs `MathExpression`, server-log-only errors, Python-`re` regex, `AnythingToInt` crashes, inclusive `rangeInt` `num_steps`. ## Cross-refs - `comfy-conditionals` — feeding math output through a comparator to form a boolean predicate. - `comfy-debug-preview` — `ShowAnything` / `DisplayAny` / `ShowFloat` for inspecting intermediate math results. - `comfy-flow-control` — `easy rangeInt` feeding `forLoopStart`; primitives as switch selectors. - `comfy-prompting` — string assembly for prompts (this skill is the primitive layer; `comfy-prompting` is the application). - Project CLAUDE.md "SaveImage filename substitution" — native `%date:%`/`%NodeName.widget%` syntax that complements the string-graph approach. ## Things this skill does NOT cover - **Animation schedulers** — `DreamSineWave`, `DreamSawWave`, `DreamTriangleWave`, `FloatsToWeightsStrategy`, frame-counter ops. These are math primitives but their application (AnimateDiff / IPAdapter transitions / weight schedules over frames) is its own domain. Future `comfy-animation-schedules` skill will cover this. For now: the nodes exist, they emit FLOATs / FLOAT lists driven by a frame index; consult the `comfyui-dream-project` and `comfyui_yvann-nodes` repos for application examples. - **Display-only nodes** — `ShowText`, `DisplayAny`, `ShowFloat`, Crystools `CConsoleAny*`. Those are inspection, not computation; see `comfy-debug-preview`. - **Image / mask arithmetic** — `ImageBlend`, `MaskComposite`. Those are pixel ops, not scalar math; see `comfy-image-utils`. - **Sampler internals** — `cfg`, `denoise`, step counts. Math-driven scheduling of those values is fine, but the values themselves live in the model-family skills.