find function in IML

[model_coder]

Is there a find function in IML that will let me find indices of nonzero elements? For example I = Find(X[,1]=2) should return indices for all rows in matrix X where the first column value is equal to 2.
One option is to implement this function as a subroutine and call this from my program. But I have peformance concerns as I call this function several times in my code.
Any help will be appreciated.

[model_coder]

I found the loc function that does exactly what I want. Thanks.