On Mon, Sep 20, 2010 at 3:23 PM, Gökhan Sever <gokhanse...@gmail.com> wrote: > On Mon, Sep 20, 2010 at 1:05 PM, Robert Kern <robert.k...@gmail.com> wrote: >> >> Are you asking about when masked arrays are casted to ndarrays (and >> thus losing the mask information)? Most times when a function uses >> asarray() or array() to explicitly cast the inputs to an ndarray. The >> reason that np.mean() gives the same result as np.ma.mean() is that it >> simply defers to the .mean() method on the object, so it works as >> expected on a masked array. Many other functions will not. >> >> -- >> Robert Kern > > Right guess. It is important for me to able to preserve masked array > properties of an array. Otherwise losing the mask information yields > unexpected results in some of my calculations. I could see from np.mean?? > that mean function is indeed the object method. Also in /numpy/ma there is a > conversion for np.zeros(). I guess in any case it is the user's > responsibility to make sure that the operations are performed on a desired > array type.
True, but in some cases the functions just blindly call asarray() or array() without thinking about using asanyarray(). If you encounter a basic numpy function that calls asarray() but would work fine with masked arrays (or other subclasses), feel free to file/post as a bug. It's good to get those cases fixed where possible. (I've done this in the past.) Ryan -- Ryan May Graduate Research Assistant School of Meteorology University of Oklahoma _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
