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Find sum of elements in a cell along the columns

Asked by Vishakha Ramani on 9 Sep 2019
Latest activity Answered by Jacob Shulman on 9 Sep 2019
Hi all,
I have a 3D cell A with dimensions 3x5x2. An example of elements along row 2, all columns and z dimension = 1 is:
x = A(2,:,1)
x = [ ] [ ] 5.1 [ ] 7.9
I would like to add up the non zero entries and get the number of non zero entries in this resulting array. I tried using:
y = sum([A(2,:,1)])
and
y = cumsum([A(2,:,1)])
But got the following error:
"Error using sum
Invalid data type. First argument must be numeric or logical."
Could anyone please help me with this and would kindly let me know the procedure to solve such problems.

  1 Comment

Could you please load your data in a mat file?

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2 Answers

Answer by James Tursa
on 9 Sep 2019
Edited by James Tursa
on 9 Sep 2019
 Accepted Answer

Is this what you are trying to do? (using the curly braces)
y = sum([A{2,:,1}])

  1 Comment

Thank you. Can't believe this was that simple. Also, could you please tell me how would you find the number of non-zero entries in such a case?

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Answer by Jacob Shulman on 9 Sep 2019

A=cell(2,2,2)
A{2,1,1}=1;
A{2,2,1}=2;
B=0;
[rows,columns,depth]=size(A);
for i=1:rows
for j=1:columns
if nonzeros(A{i,j,1})
B=B+1;
end
end
end
y = sum([A{2,:,1}])
B
The function nonzeros will not count zeros or blanks.

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