how would i make this tricky switch case

Question

nathanial hapeman 2011-10-8

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so im making a for loop and inside the for loop i want to have a certain block of code which is either initiated or not. i know i could use a if command but then the computer would have to process that "if" command for how ever many iterations the for loop is. so how would u code the statement below so that a = %{ and b=%} if a certain criteria is asked for?

for i=1:10

a block of code b

end

thanks!!!

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Jan 2011-10-8

The question is not clear to me. Can you insert a running example? Valid Matlab syntax is understood by more users than the term "a block of code b".

Fangjun Jiang 2011-11-13

I don't understand the question either!

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Answer 1

Walter Roberson 2011-10-8

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MATLAB does not offer pre-processing of that form.

If you do not want the condition executed however many times, put the test a single time in an if statement, and code the section twice, once with and once without the conditional code.

if theCondition
  for i=1:10
    block of code
    second block of code
  end
else
  for i=1:10
    second block of code
  end
end

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Answer 2

Harry MacDowel 2011-10-8

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help switch

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Answer 3

Jan 2011-10-8

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What's wrong with the IF method? It will cost some milliseconds, while writing this question costs a minute.

Perhaps the problem is getting clear, if you post the relevant part of the program and measure the delay caused by the IF, e.g. by inserting the IF twice.