function nbDeZero = EstMatriceCreuse(matrice)
matrice = [1,2,3,0,0,0,0,0;1,2,3,4,5,0,0,0];
validateattributes(matrice,{'double'},{'2d','nonempty'})
[m,n] = size(matrice);
o = 0 ;
for i = 1 : m
for j = 1 : n
if matrice(m,n) == 0
o = o + 1;
end
end
end
fprintf('%d',o);
end
For some reason my variable o increments everytime...even if the number is not zero. I'm kinda of a newbie so I don't know what is the problem. please help.

 采纳的回答

Jan
Jan 2022-3-8
编辑:Jan 2022-3-10

1 个投票

Replace
if matrice(m,n) == 0
by
if matrice(i,j) == 0
Currently you are checking the last element of the matrix in each iteration.
A standard method to examine such problems is to add some output of the currently processed element to the command window.
By the way, the singular of "matrices" is "matrix".
Some matlabish way to count the zero elements: [EDITED, thanks Image Analyst!]
sum(A(:) == 0)
numel(A) - nnz(A)

5 个评论

DGM
DGM 2022-3-8
matrice creuse : sparse matrix
... not that I'm any authority on other languages. That's just what I get when I point my translator plugin at it.
For the second one, I assume you meant
numNonZeros = nnz(A)
Jan
Jan 2022-3-9
@Image Analyst: The OP counts the number of zeros, so numel(A)-nnz(A) is correct. Or nnz(~A) .
OK, but at the end of your comment you said:
"Some matlabish way to count the non-zero elements:"
sum(A(:) == 0)
numel(A) - nnz(A)
"nnz(A)" is the number of non-zeros, not "numel(A)-nnz(A)"
That's what I was referring to.
I guess you really meant "Some matlabish way to count the zero elements:"
Jan
Jan 2022-3-10
Ah, yes. Thanks. I've fixed it.

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更多回答(1 个)

Image Analyst
Image Analyst 2022-3-9

0 个投票

Get rid of this line
matrice = [1,2,3,0,0,0,0,0;1,2,3,4,5,0,0,0];
because it just blows away any matrix you pass in via the argument list.
Also you're using the wrong indexes in
if matrice(m,n) == 0
That just looks at the very last element in the lower right corner of the matrix.
It should be
if matrice(j, i) == 0
Plus you're never assigning nbDeZero. You need to do
nbDeZero = o;
at the end of the function. Also don't use o as the variable name because it looks too much like 0. Use numNonZeros or some other descriptive variable name.

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