problems using && with dropdown list result

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Muazma Ali
Muazma Ali 2019-9-24
编辑： Muazma Ali 2019-9-24
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..
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the cyclist
the cyclist 2019-9-24
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
Muazma Ali 2019-9-24
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

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采纳的回答

the cyclist
the cyclist 2019-9-24
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'.

更多回答（1 个）

the cyclist
the cyclist 2019-9-24
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).
  2 个评论
Muazma Ali
Muazma Ali 2019-9-24
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
Guillaume 2019-9-24
Maybe the OP wants all instead of any. I.e all the selections must be NH4Cl or CaCl2
if all(ismember(result, [1 3]))

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