In one sentence:

fastaread is a built-in function of the bioinformatics toolbox.

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Script for testing merfish subsequent analysis./example_scripts/    An error message appears in analysis_script. M:

Error using CodebookToMap (line 54)

The provided path is not to a valid if ! fasta file.

Locate the code error and find the following

if ischar(codebook)
    if ~exist(codebook, 'file')
        error('matlabFunctions:invalidArguments', 'The provided path is not to a valid file.');
    else
        try
            codebook = fastaread(codebook);
        catch
            error('matlabFunctions:invalidArguments', 'The provided path is not to a valid if !fasta file.');
        end
    end
end

Then it is found that MATLAB can’t find this function at all

At first, I thought this was a custom function of the code, and the file was not downloaded back. The browser search post-discovery function fastaread is a function in the bioinformatics toolbox. So you should reinstall the toolbox first.