Check if the value for a field in a struct exists

A struct can have a field name with no value. For example:

A=struct('a',{})

How can I check if this is the case?

I tried

isempty(A.a)

But an error says not enough input arguments.

Answer 1

[Walter Roberson]

A=struct('a', {})

A = 

  0x0 empty struct array with fields:

    a

isempty(A)

ans = logical
   1

isempty(A) || isempty(A.a)

ans = logical
   1

[black cat]

Thanks Walter!

Answer 2

[Matt J]

Watch your struct() syntax,

A=struct('a',[]) %field 'a' with empty matrix 

A = struct with fields:
    a: []

isempty(A.a)

ans = logical
   1

B=struct('a',{{}}) %field 'a' with empty cell array 

B = struct with fields:
    a: {}

isempty(B.a)

ans = logical
   1