how would i make this tricky switch case

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!!!

[Jan]

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]

I don't understand the question either!

Answer 1

[Walter Roberson]

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

Answer 2

[Harry MacDowel]

help switch

Answer 3

[Jan]

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.