MATLAB export of strings

Hello,

I have noticed that during conversion of a log file to a .mat file, fields with strings are replaced with a 0.

Such an example is the MODE message, as well as the MSG message.

Specifically, all message container variables are doubles. Clearly is specific cases cell variables are needed.

Locate the MATLAB/.mat export path in Mission Planner and reproduce conversion of a log containing MODE and MSG messages. Trace how string fields are represented in the message containers; done means those strings are preserved in the exported MAT file instead of being replaced with 0.

Written by the indexing model from the issue text.