matlab find function implementation in opencv?

Question

I have this matlab code ,where i tried to find the 'j' in matrix color.I cant find a usefull function in opencv which can do the same job like matlab find do.i have tried some iterative method with 3 for loops ,but that were too cumbersome,Can you guys help me out?

if (find(Colorr==j))
    tt=tt+1;
    test=[test;ColorValues(:,j,1),ColorValues(:,j,2),ColorValues(:,j,3)];
end

this is the code i have written to covert to opencv

for(j=0;j<ColorValues.cols/2;j++)
    for(i=0;i<Color.cols;i++){
        if(j=input[Color.step*i+1]){
            tt++;
            for(k=0;k<ColorValues.rows;k++){

            }
        }

    }

this find command will be very use full,if we can implement it in opencv. — Ishant Mrinal, Jul 15 '13 at 10:42
Maybe an [already implemented operation](http://docs.opencv.org/modules/core/doc/operations_on_arrays.html) could fit you. Maybe, the best choice you have is the cumbersome way. An idea would be e.g. to modify minMaxIdx() and return a container with desired indexes. — LovaBill, Jul 15 '13 at 11:39
i am beginner in opencv. So could not understand all function well. Can you please elaborate little — Ishant Mrinal, Jul 15 '13 at 12:28
Check [this](http://stackoverflow.com/questions/12070139/opencv-read-matrix-value). — LovaBill, Jul 15 '13 at 13:16
i hope my code will do this job..but i need simple function rather this cumbersome code, since sometimes this may cause runtime problem. — Ishant Mrinal, Jul 15 '13 at 14:43
It's difficult to tell exactly what you want. What is the actual operation you wish to perform? — Aurelius, Jul 15 '13 at 15:02
i have a matrix 'color' having 1 rows and 'n' number of columns, i want to check whether the matrix contain 'j' as its data. if so, then rest of the operation will be performed. — Ishant Mrinal, Jul 15 '13 at 15:10
if you think my question is use full, do not forget to vote it up — Ishant Mrinal, Jul 15 '13 at 15:57

score 3 · Accepted Answer · answered Jul 15 '13 at 15:29

Assuming Color is a properly initialized single-channel cv::Mat, you can use the combination of overloaded operator== and cv::countNonZero() to do what you wish. operator== returns a mask where each element is one if the value in Color matches j, or zero otherwise.

if(cv::countNonZero(Color == j))
{
   // Do something...
}

matlab find function implementation in opencv?

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