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isShuffleable

Determine whether datastore is shuffleable

Since R2020a

Description

example

tf = isShuffleable(dst) returns logical 1 (true) if the datastore dst is shuffleable and logical 0 (false) otherwise.

You can use the shuffle function on shuffleable datastores to randomize the ordering of files while preserving the row associations of files in different datastores.

Examples

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When you have a matlab.io.datastore.SimulationDatastore object that contains big data from a simulation, you can determine the shuffleability of the SimulationDatastore using the isShuffleable function.

Log Big Data from Model

Open the example model sldemo_fuelsys.

mdl = "sldemo_fuelsys";
open_system(mdl)

Select Configuration Parameters > Data Import/Export > Log Dataset data to file. Alternatively, you can use the set_param function to log simulation data logged using the Dataset format to a MAT-file instead of the workspace.

set_param(mdl,"LoggingToFile","on")

Simulate the model.

sim(mdl)

The MAT-file out.mat appears in your current folder. Logged signal data is stored in the MAT-file with the variable name sldemo_fuelsys_out.

Create a DatasetRef object that refers to the logged signal data.

DSRef = Simulink.SimulationData.DatasetRef("out.mat","sldemo_fuelsys_output");

Preview Big Data

Use curly braces to extract the signal named fuel, which is the tenth element in DSRef, as a Simulink.SimulationData.Signal object. The SimulationDatastore object exists in the in the Values property of the returned Singal object named SimDataSig.

SimDataSig = DSRef{10};
DStore = SimDataSig.Values;

Determine whether the datastore is shuffleable.

if isShuffleable(DStore)
    disp("Datastore is shuffleable.")
else
    disp("Datatstore is not shuffleable.")
end
Datatstore is not shuffleable.

Input Arguments

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Input datastore. You can use these datastores as input:

  • MATLAB® datastores — Datastores created using MATLAB datastore functions. For a complete list of datastores, see Select Datastore for File Format or Application.

  • Combined and transformed datastores — Datastores created using the combine and transform functions.

  • Custom datastores — Datastores created using the custom datastore framework. Any datastore that subclasses from matlab.io.Datastore supports the isShuffleable function. See Develop Custom Datastore for more information.

Version History

Introduced in R2020a