coding a conditional for loop

I would like to know what code I need to write a conditional for loop. More specifically, I want to check a list of values to see if they make an equation > a certain number. Then I want to continue using the values that fit the condition in the rest of my code. If they don't fit the condition then I don't want them used. Can anybody help me with this?

Answer 1

[Walter Roberson]

MATLAB does not have conditional for loops. MATLAB does however support code of the form

if some condition
   for variable = range
     some statement
   end
end

and

for variable = range
   if some condition
     some statement
   end
end

The first one checks the condition once and if it is true then runs the entire for loop to completion and otherwise does not run the for loop at all. The second one runs the for loop and for each iteration of the loop tests the condition and if the condition is true executes the statement.

If you wish to exit a for loop early then you can use "break". For example,

for variable = range
   t = cos(variable);
   if t < -0.88
      break
   end
   some statement
end

This would exit the for loop the first time that cos(variable) < -0.88

[K Kee]

this is very helpful. what would go in the "statement" position?

[Walter Roberson]

What would go in the "statement" position is the using the values" part of "Then I want to continue using the values that fit the condition in the rest of my code"

Answer 2

[William Gaillard]

Couldn't you use a while loop to accomplish the same thing

[Walter Roberson]

When I re-read the question, it now looks to me as if the general form should be:

values_to_try = .... something appropriate
y = SomeFunction(values_to_try);
mask = y > a_certain_number;
selected_values = values_to_try(mask);

and then proceed to process selected_values