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Error in using eval statement

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Ramesh Bala
Ramesh Bala il 10 Gen 2022
Modificato: Stephen23 il 10 Gen 2022
Why it shows an incomplete statement ?
I'm trying to write this statement using eval as follows : Energy_H_A1S1 = rms (H_A1S1); but in eval it shows error ?
Thanks in advance.
eval(['Energy_H_A',num2str(1),'S',num2str(1),' = rms(H_A',num2str(1),'S',num2str(1);]);
  2 Commenti
Stephen23
Stephen23 il 10 Gen 2022
Modificato: Stephen23 il 10 Gen 2022
"I'm trying to write this statement using eval as follows : Energy_H_A1S1 = ..."
And that is the start of your problems.
Forcing meta-data into variable names makes acessing your data complex, slow, inefficient, and buggy... as your question demonstrates. Meta-data is data. Data should be stored in variables, not in variable names.
Your poor data design forces you into writing bad code, which could be easily avoided by storing the meta-data correctly.
Ramesh Bala
Ramesh Bala il 10 Gen 2022
Thank you Stephen for your valuable reply.Yes that's right using names was wrong as it was indeed slow.

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Risposta accettata

Paul
Paul il 10 Gen 2022
There's almost certainly a better way to organize the data and store the results, but if you must use eval:
['Energy_H_A',num2str(1),'S',num2str(1),' = rms(H_A',num2str(1),'S',num2str(1);]
ans = 'Energy_H_A1S1 = rms(H_A1S1'
should be:
['Energy_H_A',num2str(1),'S',num2str(1),' = rms(H_A',num2str(1),'S',num2str(1),');']
ans = 'Energy_H_A1S1 = rms(H_A1S1);'
  4 Commenti
Paul
Paul il 10 Gen 2022
Alternatives are dicussed in the link posted by @Walter Roberson in his comment.
Stephen23
Stephen23 il 10 Gen 2022
Modificato: Stephen23 il 10 Gen 2022
"Could you please also post an example of the mentioned better way instead of eval as it takes high running time for this varying A1..4..S1..4 data"
The MATLAB introductory tutorials also show how to use MATLAB effectively by using arrays and indexing:

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Più risposte (1)

Walter Roberson
Walter Roberson il 10 Gen 2022
Asking how to use eval without problems is like asking how to use a chainsaw without its chain guard. It would be irresponsible for us to answer in any way other than "Don't do that!"
  1 Commento
Ramesh Bala
Ramesh Bala il 10 Gen 2022
Thank you Walter ,Indeed Eval was causing slowness when runnign the code.Thank you for the link

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