remove

Remove entries from ValueStore or FileStore object

Since R2022a

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Syntax

remove(store,keySet)

Description

remove(store,keySet) removes key-value or key-file pairs from the ValueStore or FileStore object store as specified by the keys keySet.

example

Examples

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Open Live Script

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. Remove entries from this object as specified by their corresponding keys.

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. Show the keys of the object.

store = job.ValueStore;
keys(store)
ans = 4×1 string
    "result_1"
    "result_2"
    "result_3"
    "result_4"

Remove multiple entries as specified by the keys "result_1" and "result_4" from the object.

remove(store,["result_1","result_4"]);

You can also remove an entry using the syntax store(key) = []. Remove the entry as specified by the key "result_3" from the object.

store("result_3") = [];

Show the keys of the updated object.

keys(store)
ans = 
"result_2"
Open Live Script

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. Remove entries from this object as specified by its corresponding keys.

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

Remove the key-file entries as specified by the keys "result_1" and "result_2" from the object. Show the keys of the updated object.

remove(store,["result_1","result_2"]);
keys(store)
ans = 2×1 string
    "result_3"
    "result_4"

Input Arguments

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

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

Tips

  • For a ValueStore object, you can also use the syntax store(key) = [] to remove only one key-value entry as specified by key.

Version History

Introduced in R2022a

See Also

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