Why is my if statement breaking when condition is not met?

So I have a program that sets verbose to either 'true' or 'false'

I have the code

if (verbose == 'true')
  fprintf('VERBOSE MODE\n');
end

disp(verbose);

If verbose is 'true', there is no problem.

However, if verbose is 'false', my code just quits completely- it won't disp(verbose) for example.

Why is this? I thought my code would just skip over this and continue on if the condition is not fulfilled.

Note: I even tested this by adding in an else statement, and that seems to not even work either. Furthermore, I changed the first line to

if (verbose == 'false')

and I got the right output, so what could be causing the breakdown when the statement is

if (verbose == 'true')

Answer 1

[James Tursa]

The == operator is an element-wise operator. You need to use a string comparison function for this. E.g.,

if( strcmpi(verbose,'true') )

That's assuming you really are working with character strings and not logical variables. If verbose is in fact a logical variable, then you would just do this:

    if( verbose )

What is class(verbose)?

Answer 2

[Steven Lord]

'false' is not the same length as 'true' so this will error.

'false' == 'true'

Since you said "my code just quits completely" you must have this block of code wrapped in a try / catch block.

Use isequal or strcmp (or strcmpi if you want case-insensitive comparison) or compare the verbose variable to the string "true" or "false" (note the double quotes.)

verbose = 'false';
willBeFalse(1) = isequal(verbose, 'true');
willBeFalse(2) = strcmp(verbose, 'true');
willBeFalse(3) = verbose == "true"

verbose = 'true';
willBeTrue(1) = isequal(verbose, 'true');
willBeTrue(2) = strcmp(verbose, 'true');
willBeTrue(3) = verbose == "true"