On Mon, Aug 10, 2009 at 14:19, Maria Liukis<liu...@usc.edu> wrote: > Hello everybody, > I'm using following versions of Scipy and Numpy packages: >>>> scipy.__version__ > '0.7.1' >>>> np.__version__ > '1.3.0' > My code uses boolean array to filter 2-dimensional array which sometimes > happens to be an empty array. It seems like I have to take special care when > dimension I'm filtering is zero, otherwise I'm getting an "IndexError: > invalid index" exception: >>>> import numpy as np >>>> a = np.zeros((2,10)) >>>> a > array([[ 1., 1., 1., 1., 1., 1., 1., 1., 1., 1.], > [ 1., 1., 1., 1., 1., 1., 1., 1., 1., 1.]])
If that were actually your output from zeros(), that would definitely be a bug. :-) >>>> filter_array = np.zeros(2,) >>>> filter_array > array([False, False], dtype=bool) >>>> a[filter_array,:] > array([], shape=(0, 10), dtype=float64) >>>>>>> > > Now if filtered dimension is zero: >>>> a = np.ones((0,10)) >>>> a > array([], shape=(0, 10), dtype=float64) >>>> filter_array = np.zeros((0,), dtype=bool) >>>> filter_array > array([], dtype=bool) >>>> filter_array.shape > (0,) >>>> a.shape > (0, 10) >>>> a[filter_array,:] > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > IndexError: invalid index >>>> > Would somebody know if it's an expected behavior, a package bug or am I > doing something wrong? I would call it a bug. It's a corner case that we should probably handle gracefully rather than raising an exception. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
