Something like the below works fairly well. Use cellfun to search for numeric values, and save them into the doubles array. Then convert everything else into NaNs (or whatever else you want the NaNs to be).
cr_double = zeros(size(cr_manual))
cr_number = cellfun(@(x) isnumeric(x),cr_manual)
cr_double(cr_number) = [cr_manual{cr_number}]
cr_double(~cr_number) = NaN
