How can i manage a wrong input, whitout restart the my script ?

I'm writing a script that works whit many input that have to be typed chosing from different possile case.

How can i re-load the question for input if a not allowed choice is typed?

For example consider this script for converting a temperature value from Celsius to Kelvin and inverse (This script works on Matlab but not here!)

clc
T=input ("Set the value of the temperature to convert " );

Unable to run the 'fevalJSON' function because it calls the 'input' function, which is not supported for this product offering.

A=input ('Choose the unit of measure (C for Celsius or K for Kelvin )', 's');

switch A
case 'C' 
A= T+273.15
case 'K'
A=T-273.15
end

So, how can i manage a wrong input ?

For example if i digit 'F' instead of 'C or 'K' ant the input A=Input( 'Choose the unit of measure (C for Celsius or K for Kelvin )) i would obtain only an error message.I would like to set the script in such a way that it can automatically restart the from the missed input

Answer 1

[Voss]

Generally, for this method of gathering user input, you would use a while loop that iterates until the input is valid.

Something like this:

is_valid = false;

while ~is_valid
    
    A = input('Choose the unit of measure (C for Celsius or K for Kelvin )', 's');
    
    if ismember(A,{'C','K'})
        is_valid = true;
    end
    
end

Or, equivalently:

while true
    
    A = input('Choose the unit of measure (C for Celsius or K for Kelvin )', 's');
    
    if ismember(A,{'C','K'})
        break
    end
    
end

[Pietro Fiondella]

Thanks a lot.

And what about the first input? I men how to reset the choice for input T T=input ("Set the value of the temperature to convert " ); if i type for example 'S' or something that is not a number?

[Voss]

Try this:

while true
    T = str2double(input('Set the value of the temperature to convert ', 's'));
    if ~isnan(T)
        break
    end
end

str2double returns NaN for non-numeric input.