isKey

Determine if ValueStore or FileStore object contains keys

Since R2022a

Syntax

TF = isKey(store,keySet)

Description

TF = isKey(store,keySet) returns a logical array containing 1 (true) for each key as specified in keySet that exists in the ValueStore or FileStore object store, and 0 (false) otherwise.

Examples

Check Keys of ValueStore Object

Run a simulation on workers and retrieve the data storage of the job on a client. The data storage is a ValueStore object with key-value entries. Check whether the specified keys exist in this object.

The following simulation finds the inverse of random matrices and stores the results in the ValueStore object.

type workerInvCode

function workerInvCode(models)
% Get the ValueStore of the current job
store = getCurrentValueStore;
for i = 1:numel(models)
    % Store simulation results in the ValueStore object
    pause(1);
    key = strcat("result_",num2str(i));
    store(key) = inv(rand(models(i)));
end
end

Run a batch job on workers using the default cluster profile.

models = [4,8,32,20];
c = parcluster;
job = batch(c,@workerInvCode,0,{models});
wait(job);

Retrieve the ValueStore object on the client.

store = job.ValueStore;

Show the keys of this object.

keys(store)

ans = 4×1 string
    "result_1"
    "result_2"
    "result_3"
    "result_4"

Check whether the following specified keys exist in the ValueStore object.

TF = isKey(store,["result_2", "result_5", "result_3"])

TF = 1×3 logical array

   1   0   1

Check Keys of FileStore Object

Run a simulation on a parallel pool of process workers and retrieve the file storage on a client. The file storage is a FileStore object with key-file entries. Check whether the specified keys exist in this object.

The following simulation finds the average and standard deviation of random matrices and stores the results in the FileStore object.

type workerStatsCode

function workerStatsCode(models)
% Get the FileStore of the current job
store = getCurrentFileStore;
for i = 1:numel(models)
    % Compute the average and standard deviation of random matrices
    A = rand(models(i));
    M = mean(A);
    S = std(A);
    % Save simulation results in temporary files
    sourceTempFile = strcat(tempname("C:\myTempFolder"),".mat");
    save(sourceTempFile,"M","S");
    % Copy files to FileStore object as key-file pairs
    key = strcat("result_",num2str(i));
    copyFileToStore(store,sourceTempFile,key);
end
end

Start a parallel pool of process workers.

pool = parpool('Processes');

Starting parallel pool (parpool) using the 'Processes' profile ...
Connected to the parallel pool (number of workers: 6).

Get the FileStore for this pool.

store = pool.FileStore;

Run the simulation on the pool.

models = [4,8,32,20];
future = parfeval(@workerStatsCode,0,models);
wait(future);

Show the keys of the FileStore object.

keys(store)

Check whether the following specified keys exist in the FileStore object.

TF = isKey(store,["result_2", "result_5", "result_3"])

Input Arguments

store — Data or file storage shared by MATLAB^® clients and workers

ValueStore object | FileStore object

Data or file storage shared by MATLAB clients and workers, specified as a ValueStore or FileStore object.

keySet — Keys to search for

character vector | string scalar | string array | cell array of character vectors or strings

Keys to search for, specified as a character vector, string scalar, string array, or cell array of character vectors or strings.

Version History

Introduced in R2022a