matrix

if i want to find the index of certain value in 2D matrix, how can I find that? e.g: I have a 300x300 matrix. There is a value 90096 in that matriz. I want to find its index. Please show me the code.

Answer 1

[Andrei Bobrov]

A =[ 191    23    37    34   154
   212    66   228    99     9
    30   128   224   215   199
   214   225   114   186   219
   148   226   188   225   159];
a = 224;
[i1,j1] = find(abs(A-a) < 100*eps);

[Walter Roberson]

Yes! If you do not know for sure that the values are integral, then using exact comparisons will often fail.

[Khawaja Asim]

thank you for answer.. Actually I have a matrix about 300x300 order app. It contains a lot of zero values and non-zero value. I want to find the index of min value other than zero. So I thought of a logic, I stored a matirx in another variable. then deleted all zeros from it. then got min value using "minimum=min(A). Now I wanted to find the index of this "minimum" from original matrix. I hope I thought of correct logic :-)

Answer 2

[Jim]

you can use find command to know the index of values in matrix

Answer 3

[C.J. Harris]

Using find with two return parameters might make it easier.

[row, col] = find(matrix == 90096);

[Khawaja Asim]

i tried this but dont why it didnt work :(

[Walter Roberson]

Probably the value in the matrix was not _exactly_ 90096

http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

[Khawaja Asim]

ans given by andrei worked