# How to add elements to a sparse matrix

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Paul Wolfram on 21 Aug 2018
Edited: Walter Roberson on 9 Apr 2019
Dear community,
I have a sparse matrix S with the dimensions 2028 rows by 14809 columns. I would like to turn S into a full matrix F with the dimensions 2028 rows by 14927 columns. This means that I would like to define a 2028x14927 matrix of zeros first and then fill it with the elements of S in the correct place.
Here is a small example: Below you can see the first 4 elements of the sparse matrix:
(1,1) 1
(1,2) 2
(1,3) 2
(1,6) 8
...
I would like to turn into something like this:
(1,1) 1
(1,2) 2
(1,3) 2
(1,4) 0
(1,5) 0
(1,6) 8
...
Any ideas? Thank you! Paul
Walter Roberson on 21 Aug 2018
Edited: Walter Roberson on 9 Apr 2019
I have to wonder if that is the best approach?

Julie on 21 Aug 2018
Edited: Julie on 21 Aug 2018
F=full(S)
F=[F,zeros(2028,14927-14809)];

Walter Roberson on 21 Aug 2018
S(end, 14927) = 0;
S = full(S) ;

Yokesh on 9 Apr 2019
%Create a random 10 x 10 sparse matrix
X = sprand(10,10,0.2);
%For adding elements to an existing Sparse matrix
X(2,2) = 0.025;
X(9,1) = 0.5;
for i = [2 3 5]
X(i,i) = 0.00375;
end
All these assignments will just add data to the existing Sparse matrix