I have a structure within a structure (a nested structure), and am trying to add a field to that structure, what should I write?

s.Field.(FieldName)=zeros(1,1);

Doesn't work...

Answer 1

[Fabian Schadt]

Hi Guy Nir,

actually there should be no problem.

 s.Field.FieldName = zeros(1,1);

works ;-)

However, if you state your nested struct with brackets ->

 s.Field.(FieldName),

then you access with (FieldName) a variable in your workspace. If this does not exist, you receive an error.

If brackets, then it would be like this:

 FieldName = [];
 s.Field.(FieldName) = zeros(1,1);

Hope I could help!

[Guy Nir]

Hi Fabian,

I meant that FieldName is a string variable that holds the name of the field I would like to add. For instance: FieldName='valid'; s.Field.FieldName = zeros(1,1); Gives the following error: Field assignment to a non-structure array object.

[Stephen23]

A fieldname must be a character vector, cannot be empty, and must start with a letter:

https://www.mathworks.com/help/matlab/matlab_prog/generate-field-names-from-variables.html

[Guy Nir]

You can't do it when it's a structure within a structure.

[James Tursa]

Works for me:

>> clear all
>> FieldName='valid'
FieldName =
valid
>> s.Field.(FieldName) = zeros(1,3)
s = 
    Field: [1x1 struct]
>> s.Field.valid
ans =
     0     0     0

You should double check what the variable s really is. Are you sure it isn't maybe a cell array that contains structures, or something like that?

[Guy Nir]

Thanks. It seems that because I had a 2X1 structure within a structure, it was a bit more complicated. but i got it done thanks to all of you!

fluidicsSeq{1,1}.ClustData(1).(FieldName)=zeros(1,3)