dummyvar — Create dummy-variable columns for grouping variables.
dummyvar(group) converts grouping variables into a numeric design matrix with one dummy column per level.
Syntax
D = dummyvar(group)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
X | Any | Yes | — | Input labels. |
Returns
| Name | Type | Description |
|---|---|---|
D | NumericArray | Dummy-variable design matrix. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:dummyvar:InvalidArgument | Inputs, dimensions, classes, output types, or options are malformed. | encoding: invalid argument |
RunMat:dummyvar:Internal | Internal conversion or allocation fails. | encoding: internal error |
How dummyvar works
- Numeric vector inputs use positive integer levels
1:max(group);NaNrows becomeNaNacross that grouping variable's dummy columns. - Numeric row and column vectors are treated as one grouping variable; nonscalar numeric matrices treat each column as a separate grouping variable and concatenate the dummy columns for each variable.
- Cell arrays can hold multiple grouping variables when supplied as a row cell array; cell-string vectors are encoded by first appearance.
- Categorical inputs use the full category order, including categories not observed in the input values.
- String, character-row, logical, and cell-string grouping variables are supported.
Example
Encode numeric group levels
D = dummyvar([1; 2; 1])Expected output:
D is [1 0; 0 1; 1 0].Using dummyvar with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how dummyvar changes the result.
Run a small dummyvar example, explain the result, then change one input and compare the output.
FAQ
Does dummyvar support missing labels?⌄
Yes. Numeric NaN, empty text, and <missing> text are treated as missing; missing numeric rows produce NaN dummy values.
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Ml
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Random
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Hist
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how dummyvar is executed, line by line, in Rust.
- View the source for dummyvar in Rust on GitHub
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- Found a bug? Open an issue with a minimal reproduction.
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