Main Content

Supported Data Types

Statistics and Machine Learning Toolbox™ supports the following data types for input arguments:

  • Numeric scalars, vectors, matrices, or arrays having single- or double-precision entries. These data forms have data type single or double. Examples include response variables, predictor variables, and numeric values.

  • Cell arrays of character vectors; character, string, logical, or categorical arrays; or numeric vectors for categorical variables representing grouping data. These data forms have data types cell (specifically cellstr), char, string, logical, categorical, and single or double, respectively. An example is an array of class labels in machine learning.

    • You can also use nominal or ordinal arrays for categorical data. However, the nominal and ordinal data types are not recommended. To work with nominal or ordinal categorical data, use the categorical data type instead.

    • You can use signed or unsigned integers, e.g., int8 or uint8. However:

      • Estimation functions might not support signed or unsigned integer data types for nongrouping data.

      • If you recast a single or double numeric vector containing NaN values to a signed or unsigned integer, then the software converts the NaN elements to 0.

  • Some functions support tabular arrays for heterogeneous data (for details, see Tables). The table data type contains variables of any of the data types previously listed. An example is mixed categorical and numerical predictor data for regression analysis.

    • For some functions, you can also use dataset arrays for heterogeneous data. However, the dataset data type is not recommended. To work with heterogeneous data, use the table data type if the estimation function supports it.

    • Functions that do not support the table data type support sample data of type single or double, e.g., matrices.

  • Some functions accept gpuArray (Parallel Computing Toolbox) input arguments so that they execute on the GPU. For the full list of Statistics and Machine Learning Toolbox functions that accept GPU arrays, see Function List (GPU Arrays).

  • Some functions accept tall array input arguments to work with large data sets. For the full list of Statistics and Machine Learning Toolbox functions that accept tall arrays, see Function List (Tall Arrays).

  • Some functions accept sparse matrices, i.e., matrix A such that issparse(A) returns 1. For functions that do not accept sparse matrices, recast the data to a full matrix by using full.

Statistics and Machine Learning Toolbox does not support the following data types:

  • Complex numbers.

  • Custom numeric data types, e.g., a variable that is double precision and an object.

  • Signed or unsigned numeric integers for nongrouping data, e.g., uint8 and int16.

Note

If you specify data of an unsupported type, then the software might return an error or unexpected results.