How to get rid of Warning"Unexpected use of '[' in a scalar context."

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Crystal Lee
Crystal Lee 2018-8-13
回答： David 2024-12-7
a part of the function has:
if the input A (a vector) matches what is stated, the statement runs.
if A == [1,3,3]
% statement
end
and it gives me this error: 'Unexpected use of '[' in a scalar context. How can I fix this?
  2 个评论
dpb
dpb 2018-8-13
Must be more than that; that code runs w/o any error here...
>> A=3;
>> if A==[1, 3, 3],disp('ok'),end
>> A=[1 3 3];
>> if A==[1, 3, 3],disp('ok'),end
ok
>>
Show us the context including the error message with all the text generated...
Crystal Lee
Crystal Lee 2018-8-13
There is no red text, I was just wondering if I could get rid of the orange warning.

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采纳的回答

Stephen23
Stephen23 2018-8-13
编辑：Stephen23 2018-8-13
Use all or any, like this:
if all(A==[1,3,3])
Or right-click the pop-up warning box and follow the instructions to suppress it.
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Stephen23
Stephen23 2020-9-17
编辑：Stephen23 2020-9-17
"What the explanation for the "all" fix the warning?"
Given a vector input the output from all is scalar. A scalar condition is easier to understand, which is why it is recommended by that warning.

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更多回答（2 个）

KSSV
KSSV 2018-8-13
When you use A == [1 3 3] ;
With this operator ==, MATLAB expects a scalar value, but the way used here, it gives array as output. So the warning pops out. The way you use, won't work out. YOu need to use the operator == with a scalar value, so the if condition works fine.
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David
David 2024-12-7
You may want to use isequal instead of == for that use case.

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