Switch Case or if-else?

Hello,

I'm writing a script which calculates a value of "R" which is then compared to several inequality limits. The limits are:

R <= 1.2

1.2 < R <= 1.45

1.45 < R <= 1.66

1.66 < R <= 1.93

R > 1.93

Once R satisfies the conditional statement a subroutine is prompted and 1 of 5 subsequent scripts is run.

Is switch case or if-else better for this?

Answer 1

[Atsushi Ueno]

Switch statement cannot judge the range of R. It may be possible but it must be very tricky.

Execute one of several groups of statements - MATLAB switch case otherwise - MathWorks

• A case_expression cannot include relational operators such as < or > for comparison against the switch_expression. To test for inequality, use if, elseif, else statements.

if (R <= 1.2)
    disp('if-else condition 1');
elseif (R <= 1.45)
    disp('if-else condition 2');
elseif (R <= 1.66)
    disp('if-else condition 3');
elseif (R <= 1.93)
    disp('if-else condition 4');
else % R > 1.93
    disp('if-else condition 5');
end

I would use this method.

index = find(R <= [1.2 1.45 1.66 1.93 inf], 1, 'first');
disp(['if-else condition ' num2str(index)]);

[Sean Rubino]

Thank you,

I used the if, elseif, else statements and it worked out. Now I need the output to run the script from the selected range.

Do you have insight on the command for that?

[Sean Rubino]

I figured it out! Thank you for your help.

[Atsushi Ueno]

Thank you.

I don't know what script you are writing is. Is it MATLAB function? or other language script?

Please show something about what you are writing, at least interface...

[Sean Rubino]

  if R <= 1.2;
      disp('Uniform Illumination');
      Uni_Ill
   elseif R <= 1.45;
      disp('Cosine Illumination');
      Cos_Ill
   elseif R <= 1.66;
       .
       .
       .

MATLAB script. I got it to work out for what I am doing. I'm sure I'll be tweaking things but this is a start.

Answer 2

[Dyuman Joshi]

if-else would be better in this case because you have a range of values of R (a variable).

switch is useful when you have descrete values of a variable.

Answer 3

[Stephen23]

"Switch statement cannot judge the range of R. It may be possible but it must be very tricky."

switch true
    case R <= 1.2
        disp('condition 1');
    case R <= 1.45
        disp('condition 2');
    case R <= 1.66
        disp('condition 3');
    case R <= 1.93
        disp('condition 4');
    otherwise % R > 1.93
        disp('condition 5');
end