Why setAttribute fails when passing one string as the value in 2016b?

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Hadi Salimi 2020-9-29

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评论： Walter Roberson 2020-9-29

I am trying to extract the information of the a simulink.busElement class and write them into one xml file like this:

newSigElem = docNode.createElement('SignalElement'); % creating a new xml element

parentElement.appendChild(newSigElem);

newSigElem.setAttribute('Name', busElem.Name); % works with all versions. (busElem is of type simulink.busElement)

newSigElem.setAttribute('Dimensions', string(busElem.Dimensions)); % fails on Matlab 2016b, but work fine with 2017b+

newSigElem.setAttribute('SampleTime', string(busElem.SampleTime)); % fails on Matlab 2016b, but work fine with 2017b+

But the above code fails to be executed on Matlab 2016b. It works fine with Matlab 2017b and later. Can someone tell me why the failure happening? How can I change the code to work on 2016b as well?

Thanks

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Answer 1

Walter Roberson 2020-9-29

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string objects were introduced in r2016b, and it took a couple of releases for them to be accepted by all functions. Simulink in particular lagged behind: some parts of Simulink did not accept string objects until R2017b (and even later for some more obscure parts)

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Hadi Salimi 2020-9-29

Thanks Walter for the answer.

By trial and error I found that if I convert the strings into char arrays, it works fine on all Matlab versions:

newSigElem.setAttribute('Dimensions', char(string(busElem.Dimensions)));

Is it safe to do like this for All matlab versions (2016b and later)?

Walter Roberson 2020-9-29

Yes, that should be fine.

However, there is essentially no control over how string() converts numeric values into string objects. For certainty you should consider using sprintf() or using num2str() passing in a format specification, or (r2016b and later) using compose() with a character vector for the format specification (if you use a string object for the format specification then compose() returns a string object.)

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