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Leave out dot notation in table variables

Asked by Dario Walter on 19 Jun 2019
Latest activity Edited by Stephen Cobeldick on 19 Jun 2019
Hey guys,
I am using quite a lot of functions that require the variables from a table "D". Because of that, every function has the input parameter "D". Since I do not want to redefine the variables at the beginning of each function, my question is as follows:
When it comes to calculation, it currently requires me to write "D.Speed", "D.Time" etc. instead of "Speed", "Time". Is there a way to avoid the "D." notation. In VBA, for example, you can code
% With D
% Speed....
% Time...
% end
I could not find an equivalent method in Matlab.
Your help is highly appreciated!

  3 Comments

"Since I do not want to redefine the variables at the beginning of each function"
This is very unclear: the names of any input arguments to a function (e.g. tables) is totally irrelevant to the names of variables you might use inside your function. As long as you are passing your data properly (i.e. as input and output arguments) then why does it matter what the table is called inside your function?
The name is totally irrelevant. It is just the fact that I have tons of variables inside the function and want to get rid of dot notations.
As I said: In Visual Basic for Applications you can simply write
With D
in advance so that it is clear that all variables used in the code belong to the table (so you do not have write "D.Speed" anymore but only "Speed"). And I would like to know if such an option also exists in Matlab.
"In Visual Basic for Applications you can simply write..."
MATLAB is not VB.
What is recommended, efficient, or considered to be good practice in VB does not mean that it will be efficient or good practice in MATLAB. And what you are asking about is a very bad practice in MATLAB and should be avoided.
".. I would like to know if such an option also exists in Matlab."
There are certainly ways to do this, but they are slow, complex, and very inefficient. The code that you are using now is simple, easy to debug, and very efficient. You should not change what you are doing.

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2 Answers

Answer by madhan ravi
on 19 Jun 2019
Edited by madhan ravi
on 19 Jun 2019

I don’t know why it’s hard for you to use "D." , see https://in.mathworks.com/help/matlab/matlab_prog/access-data-in-a-table.html to access table datas in different ways.

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Answer by Walter Roberson
on 19 Jun 2019

The closest MATLAB equivalent is import but it only applies for packages https://www.mathworks.com/help/matlab/matlab_oop/scoping-classes-with-packages.html not for tables .
There are ways to do it dynamically, but those ways are error prone .
You should probably just do a bunch of search-and-replace to add in the table name.

  3 Comments

Dario Walter's "Answer" moved here:
Thanks for your replies. @madhan ravi: It simply makes the code hard do read beacause you always have to include the "D." notation. A little excerpt from my code:
function D= Mode1_Calc(D)
D.Mode1_Outer_s=nan(height(D),1);
D.Mode1_Inner_s=nan(height(D),1);
for i=1:height(D)
%dbstop in Mode1_Calc at 16 if i>=31
InterSectLineX(i,:)=[D.Sinkrate_fpm(i) D.Sinkrate_fpm(i)];
InterSectLineY(i,:)=[D.RadioAlt_ft(i) 0];
end
end
@Walter Roberson: So you would leave it as it is?
Thanks a lot!
"It simply makes the code hard do read beacause you always have to include the "D." notation."
To me that notation makes it clearer to read, because then I can tell immediately where each variable is defined (which in turn this makes code easier to write, debug, and maintain). And this advantage applies to the MATLAB JIT compiler just as much as it does to me!
What you are trying to do is certainly possible, but it would be complex, liable to bugs, and inefficient. Read this to know why:
"So you would leave it as it is?"
Yes, your code is fine just as it is.
Thank you Stephen!

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