problems using && with dropdown list result

hi!

S={'NH4Cl'; 'MgCl2'; 'CaCl2'; 'ZnCl2'; 'ZnSO4'; 'NaCl'};
>> str={'Choose the combinations of salts available'};
>> result=listdlg('Promptstring',str, 'ListSize', [100,100], 'ListString', S, 'SelectionMode', 'multiple');
>> if result==1&&result==3
disp('hei')
end

the error I get: Operands to the || and && operators must be convertible to logical scalar values. Donnt understand because the output from result is scalar and is should be possible to use && togehter with scalar outputs..

[Adam]

You explictly set selection mode to 'multiple' so unless you only select one item it won't be a scalar. And if it was a scalar then

result==1&&result==3

would clearly always evaluate to false anyway! Maybe you want something more like:

all( ismember( [1,3], result ) )

[Muazma Ali]

does "all" here mean that both options have to be included in the result vector? if thats so, that s what I need :)

[the cyclist]

Muazma,

The problem with your code is clear to me (and Adam). You have allowed the user to select multiple items. For example, they might select 'NH4Cl' and 'CaCl2'. In this case,

result = [1 3]

and you are trying to evaluate

[1 3]==1 && [1 3]==3

which is

[1 0] && [0 1] % these are logical vectors

These are not allowable operands for the short-circuit logical operators. The operands must each be a single scalar value.

What is not clear to me is what you want to happen in your if statement. Perhaps you could explain this more completely.

[Muazma Ali]

Ok maybe I should write the question in another way; how can I include the whole vector in the if statement? Because i need both of the values, 1 and 3, to be true as options for the next statements

Answer 1

[the cyclist]

Here is what I think you want, based on your most recent comment:

if all(ismember([1 3],result))
   disp('hei')
end

The if statement will be entered if the user's selections include 'NH4Cl' and 'CaCl2'.

Answer 2

[the cyclist]

My best guess as to what you want is

if any(ismember(result,[1 3]))
   disp('hei')
end

The if statement will be entered if the user's selections include 'NH4Cl' or 'CaCl2' (or both).

[Muazma Ali]

I want both of them as the answer, in other words proceed with some specific statements if the user has both chosen 1tem 1 n 3 as options

[Guillaume]

Maybe the OP wants all instead of any. I.e all the selections must be NH4Cl or CaCl2

if all(ismember(result, [1 3]))