# Weird!!!! Extremely simple question!! Can't assign values to first row of a sparse matrix, please help.

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Albert on 1 Dec 2016
Answered: Albert on 1 Dec 2016
Hi, everyone
I got stuck by a very simple question. I simply can't believe that such a weird thing would happen here. I am using MATLAB 2016b.
I was trying to assign some values to a sparse matrix, but anyhow there is nothing in the first row of a sparse matrix, no matter what I give to the first row of the sparse matrix S.
Here is code:
S=sparse([],[],[],32,50,100);
s(1,21:30)=[1 1 1 1 7 5 1 1 1 1];
S(2,21:30)=[1 1 1 1 1 1 1 1 1 1];
S(3,21:30)=[1:10];
S(4,21:30)=[1 1 2 2 3 3 4 4 5 5];
The first row of matrix S is always empty. How come? What did I wrong?
Thank you very much.

James Tursa on 1 Dec 2016
Edited: James Tursa on 1 Dec 2016
Typo. You used a small case 's' in that first row assignment. Change that to an upper case 'S' and everything will be as expected. MATLAB is a case sensitive language.

Albert on 1 Dec 2016
Thank you, James.
I know MATLAB is case sensitive, but I didn't realize that I used low case of the second 'S' in my code.
It's so good to stay in MATLAB community.
Thank you.