Repeat Expression in a 'for' loop after try/catch

I have try/catch lines inside a 'for' loop as below. What I want is to repeat index 'i' if an error is encountered. However, 'i' keeps increasing to the next number depsite a line 'i = i -1'.

For example, when an error occured at i = 5, 'i' became 4 after on line 'i = i - 1'. However, it changed to i = 6 at Expression1. Please help with this. Thank you in advance.

for i = 1:10
    Expression1
    try 
        Expresssion2
    catch ME
        if strcmp(ME.message, '****')
            data(i) = [];
        end
        i = i-1;
    end
    
end

Answer 1

[woahs]

You shouldn't be changing the loop variable i in a for loop.

Normally, the loop variable is incremented at the end of the loop. No idea what you have in Expression1 and Expression2 but if you want to to know the index when an error occurs, you can just access it normally in the catch. The following code gives the resulting output:

for i = 1:10
    fprintf('Current i = %d\n', i);
    try 
        if(i == 5)
            error('error')
        end
    catch ME
        fprintf('Error at i = %d\n', i);
    end
end

Current i = 1

Current i = 2

Current i = 3

Current i = 4

Current i = 5

Error at i = 5

Current i = 6

Current i = 7

Current i = 8

Current i = 9

Current i = 10

[Doheon Lee]

That is great!! Now I realize that I did not need "data(i) = []" and "i = i-1".

Thank you very much for the help :)

[Image Analyst]

Kevin, Can you transfer your "comment" down below to the official "Answers" section?

[woahs]

Seems to already be the case?