How to stop a script if conditions are met.

I am using the 'if' function to detect if a user inputs a number that is not 5 digits long. What I would like is a function that stops the script if a certain condition is met without displaying an error message.

P.S. I'm very new to MATLAB.

[Jingyang Xie]

Hi Cory, have you solved this problem? I think I encountered the same problem...

[Paul]

A simple way to stop execution in MATLAB without throwing an error is to use the return or break statements, depending on whether the code is inside a function or loop. This prevents unwanted error messages and keeps the script clean.

Answer 1

[Walter Roberson]

To stop running a script or function and return to the invoking function or command window, use the return function. For example,

if a > b
   return
end

Any code in the current script or function that is after the return function is not run

[Hao Cheng]

"return" will terminate the current function and go back to the function that calls it. Is it possible then to stop running the entire script in GUI?

For example. A button's Callback function calls another function F. How to stop the Callback function as well if certain critieria in function F is met?

[Diaa]

This might help you. https://www.mathworks.com/help/matlab/ref/uiwait.html

[Muhammad Usman Saleem]

@Walter Roberson Sir

If i have multiple conditions and i want to run get each condition according to my requirement, then can I use if and else if condition please?

if  rcp(i,m)<0.1 & trcp(i,m) > 0.8;
    ECP{i,m}=Ecp{i,m};
elseif  recp(i,m)<0.1 & trecp(i,m) > 0.8;
    ECN{i,m}= Ecn{i,m};
elseif recnn(i,m)<0.1 & trecnn(i,m) > 0.8;
    ECNN{i,m}=   Ecnn{i,m};
elseif recl(i,m)<0.1 & trecl(i,m) > 0.8;
    ECL{i,m}= Ecl{i,m};
elseif recs(i,m)<0.1 & trecs(i,m) > 0.8;
    ECS{i,m}= Ecs{i,m};
elseif recpp(i,m)<0.1 & trecpp(i,m) > 0.8;
    ECPP{i,m}= Ecpp{i,m};
elseif recm(i,m)<0.1 & trecm(i,m) > 0.8;
    ECM{i,m}= Ecm{i,m};
elseif recy(i,m)<0.1 & trecy(i,m) > 0.8;
    ECY{i,m}= Ecy{i,m};
elseif recmm(i,m)<0.1 & trecmm(i,m) > 0.8;
    ECMM{i,m}= Ecmm{i,m};
    break, 
end

There are 9 variables inside my for loop and I want to execute my variables according to certian value which I used in if conditions. Whether for loop will continue to run till all my conditions become fulfill or just break when my first condition rcp(i,m)<0.1 & trcp(i,m) > 0.8 will be met sir?

[Muhammad Usman Saleem]

I want to stop processing on my variable when it reach my condition, I want to continue processing on my other variables untill their condition meet? Is the above logic i am using is fine or not please?

[Walter Roberson]

@Muhammad Usman Saleem

In the code you posted, the break will only happen if all of the other conditions before that are false, until finally recmm(i,m)<0.1 & trecmm(i,m) > 0.8

[Muhammad Usman Saleem]

Dear @Walter Roberson I want to run for loop untill my all 9 conditions becomes true as you highlights break will work until all above conditions before the last ones become false. How can I run for loop untill my all 9 conditions achieved please?

[Walter Roberson]

create a vector notdone = true(9,1)

while(any(notdone))

then as you do tests and find you have satisfied a condition, set notdone(ConditionNumber) = false for appropriate ConditionNumber

[Muhammad Usman Saleem]

Respected Sir @Walter Roberson, I not get the point your shared. Will you please amend this suggestion in my code shared above please?

[Walter Roberson]

notdone = true(9,1);

while any(notdone)

    if  rcp(i,m)<0.1 & trcp(i,m) > 0.8
    ECP{i,m}=Ecp{i,m};
    notdone(1) = false;
  end
  if  recp(i,m)<0.1 & trecp(i,m) > 0.8
    ECN{i,m}= Ecn{i,m};
    notdone(2)=false;
  end

%etc
end

Answer 2

[Hamid Ramezani]

you may use "error" function instead of return

[Walter Roberson]

However, "without displaying an error message" is part of the requirement here.

[Adam K]

I think a 'msgbox' to really alert the user what is the issue, and then the 'error' funcition to stop the code would be a workaround. This way the user is aware that the issue is not really an 'error' when they see the red error font.

msg = "You've got a number that is not 5 digits long";

f = msgbox(msg)

error(msg)

[Rik]

I wonder if it is possible to detect if the code is running in a try block. In such cases the message might be more confusing than simply throwing the error.

Answer 3

[Korosh Agha Mohammad Ghasemi]

To stop a script in MATLAB without displaying an error message when a user inputs a number that is not 5 digits long, you can use the return function. The return function will exit the function or script without an error message. Here is an example:

% Request user input
userInput = input('Please enter a 5-digit number: ', 's');

% Check if the input is 5 digits long
if length(userInput) ~= 5
    fprintf('Input must be a 5-digit number. Exiting script.\n');
    return;
end

% Continue with the rest of your script
disp('Input is valid. Continuing script...');
% ... rest of your script

Explanation:

1. Request User Input: Use input to get the user input as a string.
2. Check the Length: Use length to check if the input length is not equal to 5.
3. Return Function: Use return to exit the script if the condition is met, and display a message using fprintf.

This will ensure that the script stops if the user input is not a 5-digit number, and it will do so without throwing an error.