`ordinal` — Create an ordinal categorical array object.

ordinal(A) creates a categorical object whose categories are ordered. It is a compatibility constructor equivalent to categorical(..., 'Ordinal', true).

Syntax

B = tabularBuiltin(args...)

Inputs

Name	Type	Required	Default	Description
`args`	`Any`	Variadic	—	Input values and name-value options.

Returns

Name	Type	Description
`out`	`Any`	Result value.

Errors

Identifier	When	Message
`RunMat:table:InvalidArgument`	Arguments or table metadata are invalid.	`table: invalid argument`
`RunMat:table:InvalidIndex`	Table indexing is invalid.	`table: invalid index`
`RunMat:table:InvalidVariable`	A table variable name or value is invalid.	`table: invalid variable`
`RunMat:readtable:IOError`	readtable cannot open or read the requested file.	`readtable: file read failed`
`RunMat:readtable:UnsupportedFileType`	readtable receives a file type outside the text or spreadsheet import backends.	`readtable: unsupported file type`

How `ordinal` works

String, char, cellstr, numeric, and logical inputs are accepted through the same label conversion path as categorical.
ordinal(A) derives sorted unique categories from non-missing labels.
ordinal(A, categories) uses the supplied category order and marks labels not present in that list as missing.
ordinal(A, valueset, catnames) maps source values through valueset and stores the corresponding category names from catnames.
The returned object has class categorical, stores one-based category codes, and has its Ordinal metadata flag set to true.
Equality and relational operators compare category order; categorical-to-categorical comparisons require matching category lists.
min and max reduce ordinal categorical arrays by category order and return categorical results; undefined elements follow the numeric NaN behavior of includenan and omitnan, and multi-output forms return numeric indices.

Example

Create an ordered categorical array

O = ordinal({'medium'; 'low'}, {'low','medium','high'})

Expected output:

O = categorical object

Using `ordinal` with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how ordinal changes the result.

Run a small ordinal example, explain the result, then change one input and compare the output.

FAQ

How is ordinal different from categorical?⌄

ordinal always sets the categorical Ordinal flag to true, so category order is meaningful for compatibility code that checks ordinal categorical metadata.

array2table · array2timetable · categorical · cell2table · dictionary · head · iscategorical · isordinal · istable · istimetable · pivot · rowfilter · struct2table · table2array · table2cell · table2struct · table2timetable · timerange · timetable · timetable2table · uitable · vartype

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how ordinal is executed, line by line, in Rust.

View the source for ordinal in Rust on GitHub
Learn how the RunMat runtime works
Found a bug? Open an issue with a minimal reproduction.

About RunMat

RunMat is an open-source runtime that executes MATLAB-syntax code blazing on any GPU. It is licensed under the Apache 2.0 license.

RunMat automatically optimizes your math for GPU execution on Apple, Nvidia, and AMD hardware. No code changes needed. Simulations that took hours now take minutes.
Start running code in seconds. RunMat runs in the browser, on the desktop, or from the CLI. No license server, no IT ticket.

Getting started · Benchmarks · Pricing

ordinal — Create an ordinal categorical array object.