## error undefined variable 'A' or class 'A'

### Bhargavkrishna Kondreddy (view profile)

on 6 Mar 2017
Latest activity Commented on by Walter Roberson

### Walter Roberson (view profile)

on 6 Mar 2017
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

### Walter Roberson (view profile)

on 6 Mar 2017

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

Bhargavkrishna Kondreddy

### Bhargavkrishna Kondreddy (view profile)

on 6 Mar 2017
How to assign the values as the 'A' is a matrix like variable. can you please help in solving this?
Walter Roberson

### Walter Roberson (view profile)

on 6 Mar 2017
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