Operations in structure with N fields named sequencially.

2 views (last 30 days)
Jose Rego Terol
Jose Rego Terol on 31 May 2020
Commented: Stephen23 on 31 May 2020
Hi,
I created this structure (S) with 26 fields named sequencially. Each field has only one column and N number of rows (e.g. S.myfield1 (65x1), S.myfield2 (70x1), and so on). I just want to get the mean of S (all the fields).
mean_S=mean(S)
Error using sum
Invalid data type. First argument must be numeric or logical.
Error in mean (line 127)
y = sum(x, dim, flag) ./ mysize(x,dim);
So I transformed the structure into cell (struc2cell). I can get the mean of each cell (e.g. each field in the structure) but I cannot get the mean of two cells:
B=struct2cell(S);
mean_B1=mean(B{1,1});
mean_B1_26=mean(B{:,1});
Error using mean
Too many input arguments.
Also, I am interested in getting the min , max and std of S.
I could not find any page with this info regarding structure operations. Any solution?
Update*
I am looking that my structure is different as normal structure.
I load a -mat file containing 26 variables as
S=load('myfile.mat')
So, my structure is 1x1 with 26 fields. The Field is the name of each variable and the value of each field is the number of rows X number of columns (1)
  2 Comments
Stephen23
Stephen23 on 31 May 2020
"I created this structure (S) with 26 fields named sequencially."
It would be simpler and more efficient to use a non-scalar structure:

Sign in to comment.

Accepted Answer

Ameer Hamza
Ameer Hamza on 31 May 2020
Try this
y = mean(structfun(@mean, s));
  2 Comments
Ameer Hamza
Ameer Hamza on 31 May 2020
The mean() in
structfun(@mean, s)
call the mean() function on each field of the struct 's'. It will output an array. The outside mean() than take the mean of the returned array.
While writing this comment, I realized that using mean() like this will not give the correct answer. Following is the correct method
sum_s = sum(structfun(@sum, s));
num_s = sum(structfun(@numel, s));
avg = sum_s/num_s;

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!