error undefined variable 'A' or class 'A'

for k = 1:299 
    Xsum = A{k}{:,3};
    Xsum(isnan(Xsum)) = 0;
    Xsum=Xsum+A{k}(:,3);
end

after excuting getting an error as undefined variable or class

Answer 1

[Walter Roberson]

You have not assigned anything to A before you executed this.

[Bhargavkrishna Kondreddy]

How to assign the values as the 'A' is a matrix like variable. can you please help in solving this?

[Walter Roberson]

For example,

A = arrayfun(@(IDX) {IDX+[1 1.1 1.2], IDX+[2 2.1 2.2 2.3], randi(IDX, 5, 7), IDX+[4 4.1 4.2 4.3 4.4 4.5].'}, 1:299, 'Uniform', 0);

This will get you through the

    Xsum = A{k}{:,3};
    Xsum(isnan(Xsum)) = 0;

lines. It will, however, fail on your

      Xsum=Xsum+A{k}(:,3);

line.

Look more carefully at how you are using A. In the line

Xsum = A{k}{:,3};

you are declaring that A{k} is a cell array that contains cell arrays. But in

        Xsum=Xsum+A{k}(:,3);

you are declaring that A{k}(:,3) is something that can be added, which implies that A{k}(:,3) is numeric, which would require A{k} to contain a numeric array rather than a cell array.

Note: if your intention is to create a running total of all of the entries, then you need to be using the structure

   total = 0;
   for ....
      new_value = ...
      total = total + new_value;
   end