Inserting doubles into the field of a struct

Wondering if anyone knows how to insert a "double" into a struct. I was trying to use the following code to do it but I keep getting the error "Scalar structure required for this assignment."

Updating.GoodNews = Upda;

Answer 1

[Chunru]

load(websave("Updating.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1129165/Updating.mat"))
load(websave("Upda.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1129170/Upda.mat"))
whos

  Name                        Size            Bytes  Class     Attributes

  Optimism_EMA_Updating      29x1              3312  struct              
  Upda                       28x31             6944  double              
  cmdout                      1x33               66  char                

% Optimism_EMA_Updating is an array of structure
% assignment should be done for struct element
Optimism_EMA_Updating(1).GoodNews = Upda;
Optimism_EMA_Updating(1)

ans = struct with fields:
       SubID: 21760059
    GoodNews: [28×31 double]

[BA]

Thank you!

Answer 2

[Image Analyst]

It's because Updating is a structure array so you need to put Upda into a new structure in the array. This works, where I append Upda to the existing array:

% Load mat files into structures.
s1 = load('Updating.mat')
s2 = load("Upda.mat")
% Extract variables from the structures.
Optimism_EMA_Updating = s1.Optimism_EMA_Updating
Upda = s2.Upda
% Append Upda as a new structure at the end of the structure array
Optimism_EMA_Updating(end+1).SubID = Upda

[BA]

Thank you for the help! Unfortunately, I think CHunru's answer came a few seconds before yours. I wish I could accept both but I don't think I can