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POCan `eval()` be avoided? (Assign variable name at runtime)
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copied!<p>I have written a script that saves me to manually import in Matlab the data recorded during tests.</p> <p>Each test run saves around 2600 variables in <code>.csv</code> files, each with 2 header lines, two columns of data and <code>;</code> is the separator.</p> <p>The filenames come from an internal C-struct used by the monitoring program and are thus of this kind: <code>foo.bar.another.foo.bar.local_varname#VALUE.csv</code> and I want to use this to re-create the struct in Matlab in order to save only that in a <code>test_name.mat</code> file.</p> <p>Many times the <code>local_varname</code> is more than 63 char long, so I have some substitution rules in order to shorten the names without having Matlab truncating the names (and so trying to avoid naming conflicts).</p> <p>This is the code</p> <pre><code>clear all clc % Main names path_self = pwd; backslash_indices = strfind(path_self,'\'); test_name = path_self(backslash_indices(end)+1:end); % the directory name gives me the test_name % Preallocation filenames = cell(1,2600); addresses = cell(1,2600); i=0; % Full list MyFiles = dir(path_self); % Discard subdirectories and non interesting files for k=1:length(MyFiles) if ~MyFiles(k).isdir, if ~isempty(strfind(MyFiles(k).name,'#VALUE.csv')) i=i+1; % Too many files if i > length(filenames) filenames = [filenames cell(1,100)]; addresses = [addresses cell(1,100)]; end % Naming Substitution Rules %%% INSERT HERE BUNCH OF RULES % Addresses and names filenames{i} = strrep(filename,'#VALUE.csv',''); addresses{i} = fullfile(path_self, MyFiles(k).name); end end end filenames = filenames(1:i); addresses = addresses(1:i); % Check that no conflicts are created if length(filenames) ~= length(unique(filenames)) error('filenames not unique') end % Housekeeping #1 clear MyFiles backslash_indices i k path_self % Import data for j=1:length(filenames) % Read data Data = importdata(addresses{j}, ';', 2); % Assign data eval([filenames{j}, '.time = Data.data(:,1)./1000000;']); % Converted in seconds eval([filenames{j}, '.values = Data.data(:,2);']); % Let's avoid data corruption clear Data end % Housekeeping #2 clear filenames addresses j % Save data struct save(test_name, '-regexp', '^((?!name).)*$') </code></pre> <p><strong>Now my question</strong> While researching information and help to write the above code I often found people frowning upon the use of <code>eval()</code>: why is it so? In the above situation, can I avoid it?</p> <p>Thanks</p> <p><strong>EDIT</strong> As suggested by @wakjah, I tested a <code>containers.Map()</code> approach. Unfortunately is not suited to our needs, since at that point a list of keys is needed and accessing the data is not exactly friendly (remember that I have ~2600 variables, meaning at least the same number of keys)</p> <p>As for what has been asked by @Dennis Jaheruddin, the data struct is usable and does not creates any kind of conflict, even with these long varnames (given that each name* between two consecutive <code>.</code> is less than 63 chars long)</p> <p>*my apologies for not using a better technical term</p>

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