k = find(X)
[i,j] = find(X)
[i,j,s] = find(X)
k = find(X)
returns the indices of the vector X
that point to nonzero elements. If none is found, find
returns an empty matrix. If X
is a matrix, find
regards X
as X(:)
, which is the long column vector formed by concatenating the columns of X
.
[i,j] = find(X)
returns the row and column indices of the nonzero entries in the matrix X
. This is often used with sparse matrices.
[i,j,s] = find(X)
also returns a column vector of the nonzero entries in X
. Note that find(X)
and find(X ~= 0)
produce the same i
and j
, but the latter produces an s
with all 1s.
And on a matrixx = [11 0 33 0 55]';
find(x) =
1
3
5
find(x == 0) =
2
4
find(0 < x & x < 10*pi) =
1
M = magic(3)
M =
8 1 6
3 5 7
4 9 2
[i,j,m] = find(M > 6)
i =
1
3
2
j =
1
2
3
m =
1
1
1
<
,<=
,>
,>=
,==
,~=
,isempty
,nonzeros
,sparse
(c) Copyright 1994 by The MathWorks, Inc.