How to check the existance of a struct field at a given index?

p(1).name = 'name1'; p(1).value = 1:10; p(2).name = 'name2';

I want to check existance of p(2).value, but exist and empty is not working for me. How to do?

[Mr M.]

empty(p(2).value) Undefined function 'empty' for input arguments of type 'double'

[Mr M.]

exist('p(2).name')

ans =

     0

[Stephen23]

"I want to check existance of p(2).value, but exist and empty is not working for me. How to do?"

Every element of a structure array has the same fields. So if you have defined this:

p(1).name = 'name1';
p(1).value = 1:10;
p(2).name = 'name2';

Then by definition of a non-scalar structure the field p(2).value also exists. If you have not allocated it a value, then it will be initialized to the empty array. This means it is not clear what your question relates to:

• p(2).value exists because it was created as soon as you created p(1).value. So testing for its existence is entirely superfluous.
• The value of that field is []. Is that what you want to test for?

Note that exist is totally irrelevant to this problem.

empty is not a suitable MATLAB function: did you mean isempty ?

Answer 1

[madhan ravi]

Read the below link:

https://in.mathworks.com/matlabcentral/answers/328326-check-if-any-field-in-a-given-structure-is-empty#answer_257480

[Mr M.]

I think, this cannot help to me, because I dond wnat to check the hole filed, just the existance of the value of thet filed at a given index, as in the example above!

[Mr M.]

I want to check p(2).value, and not p.value!

[madhan ravi]

p(1).name = 'name1'; 
p(1).value = 1:10;
p(2).name = 'name2';

~isempty(p(2).value)

[Guillaume]

Important: as hinted by madhan's answer, the function used to test for emptiness is isempty, not empty (a completely different function that only works for classes). So instead of

empty(p(2).value)

use

isempty(p(2).value)

[madhan ravi]

Thank you Guillaume